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This is an archive of past discussions about Fructose. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Archive 2

Posts out of chronological order

Blatant contradiction in main article

There is a concern with Diabetic 1 patients and the apparent low GI of fructose. Fructose gives as high a blood sugar spike as that obtained with glucose.
Fructose is often recommended for diabetics because it does not trigger the production of insulin by pancreatic ß cells, probably because ß cells have low levels of GLUT5 [43][44][45]. Fructose has a very low glycemic index of 19 ± 2, compared with 100 for glucose and 68 ± 5 for sucrose.[46] F

I have read in many places that B) hold because fructose is much slower to digest! Someone could confirm ? —Preceding unsigned comment added by 144.85.213.163 (talk) 18:36, 11 October 2008 (UTC)

... Got some point lower in text "Why would fructose cause obesity if it's slower to digest than sacharose and also more sweeter for less calories, and also les likely to drive any addiction ..." ... Actually I think there is some strong commercial addiction sinergy pusching toward the most addictive product and I guess these forces are active here too :-( —Preceding unsigned comment added by 144.85.213.163 (talk) 18:39, 11 October 2008 (UTC)

One persons anecdotal experience forms the basic thrust of this article

Could whoever is posting this "I tried frucrose and I still had cravings" type of personal anecdotes please stop making contributions? Your own personal body chemistry and the results of your own personal dieting are very uninteresting to people reading this article. This article should reflect the current scientific consensus, not what happened to your body when you went on a fructose diet, OK? I would henceforth ask everyone to NOT contribute anecdotal evidence from their own persona lives (Sample size = 1), because its inadmissable. The lack of sources is an embarrassment. —Preceding reunsigned comment added by 134.95.90.13 (talk) 17:05, 19 September 2007 (UTC)

Plagiarism?

Interesting! I wrote/edited much of the text for Fructose in Wikipedia and can guarantee it was original. I sweated over it, trying to write it for general audience and added all the references. It is eerie to see one's work on another website, and can guarantee that mrsci.com are the plagiarists. Jwanderson 06:00, 6 April 2006 (UTC)

Sorry to but in here but this article appears wholesale at http://www.mrsci.com/Nutrition/Fructose.php with a claim and reserve of copyright. looks like someone has been a naughty boy. either this material has been plagiarised by mrsci or the author here or the author is reserving :rights at mrsci and releasing rights under the GFDL here. Tut Tut -Unsigned/Undated

The Wikipedia concept is that the articles are open for use by anyone, no? While that website obviously shouldn't be claiming to have a copyright on something that they clearly have no right to, by posting your writing on wikipedia, you lose the copyright as well, as far as I understand. Baribeau 21:19, 9 January 2007 (UTC)

No, I'm fairly certain the contributor retains ownership. They simply release the material under the GFDL. See Wikipedia:Copyrights for details. -- General Wesc 18:50, 29 April 2007 (UTC)

Some comments on the comments below:

"What do you mean that some people react badly to fructose??"

The usual obvious complaint about fructose is when excess is consumed that is not absorbed in the small intestine... it leads to gas production in the bowels and water retention... bloating, flatulence and even diarrhea. See comments in Health Effects. This is well established and well known in the medical literature.

The health effects on people are profound and ubiquitous. Most age-related chronic diseases seem to be induced by fructose consumpion. I have studied this extensively.

If you did the research yourself, it's original research, and has no place in Wikipedia Wikipedia:No_original_research. If you are referencing someone else's work, then you need to provide the reference: Wikipedia:Citing_sources and strive to make sure the sources are credible Wikipedia:Reliable_sources. This article is full of unsubstantiated statements. Leaving things in the current state is not acceptable -- if the references aren't added for the assertions, then the assertions will be removed. --Rhombus 16:45, 14 July 2007 (UTC)

"Why would fructose cause obesity if it's slower to digest than sacharose and also more sweeter for less calories, and also les likely to drive any addiction,"

I tried cutting all candy & cane sugar to my diet, switching to fruit & artificial sweeteners like saccharine, aspartame, & sucralose. Not only did I gain more weight, but I gained several cavities as well.

The article cited on obesity was only one of many. Some poorly controlled human experiments of short duration have failed to show that fructose consumption contributes to obesity. Generally the experimental failure is to not monitor total fructose consumption, which is the relevant variable; not, for example, the fructose consumption from soda pop only (a well known study did this recently, but still showed a small fructose-obesity linkage).

If so -- then cite the sources. Saying "it was only one of many" and using qualifiers like "generally" doesn't cut it. Says who? When? Where can I check it myself? --Rhombus 16:45, 14 July 2007 (UTC)

Fructose causes obesity in two ways. First, fructose tips the leptin/ghrelin balance toward fat deposition as opposed to energy production. The upshot of this is that two people eating the same number of calories may have different results... the fructose eater will slowly become more obese than a non-fructose eater on the same caloric intake, other things being equal. This effect is little noted because nearly everyone eats significant fructose; and that is 'normal.' The hormonal balance shift caused by fructose is thought to be a genetic adaptation, since in most of human history high fructose foods would have been available primarily in the late summer through fall when one would preferentially be storing some fat for the winter.

Second, fructose doesn't induce the satiety response; yet it does contain calories. This, combined with the induced hormonal shift, typically results in overconsumption and obesity. Today, when high fructose foods are eaten year-round in unprecedented quantities, people are getting obese and suffering metabolic syndrome (aka syndrome X)and other age-related chronic diseases as a result.

This article shows a positive correlation for "corn syrup" consumption and poor association for fats or carbohydrates. This very positive association existed even though they chose "corn syrup" as an indicator of "refined carbohydrate" consumption. This reflects the popular notion that "refined carbohydrates" are damaging because of poor nutrition; and does not recognize the unique role of fructose in de-regulation of appetite and satiety responses. [1] Since their "corn syrup" category includes both high fructose corn syrup (usually containing 55% fructose and 45% glucose) and plain corn syrup (typically 95%+ glucose), the effect of fructose is understated. Based on the animal studies I have reviewed, the correlation would be even more positive for total fructose consumption, since fructose appears to be the root cause, and it's effects are masked by the categories chosen for this study.

Sources, sources, sources. We're not going to take your word for it. --Rhombus 16:45, 14 July 2007 (UTC)

"...and also les likely to drive any addiction,..."

I think this is just a gratuitous comment. If you have any references to support it I would be interested.

You are begging the question. --Rhombus 16:45, 14 July 2007 (UTC)

"because it's often absorbed with fruits it's associated with many highly valuable nutriments!"

That fructose is associated with other desirable nutrients, such as the anti-oxidants in/near the peel of fruits, doesn't make it a healthful molecule to eat. Even in fresh fruit, eaten whole, the antioxidants only partially offset the oxidants, such as hydrogen peroxide, produced as side-products from glycations passing through the various reactions as they become Advanced Glycation End Products (AGEs. Fructose is especially unhealthful when dissociated from the peel and pulp, as in many fruit juice drinks. When eaten as table sugar (50% of sucrose is fructose when digested), or high fructose corn syrup, it is devoid of all nutrients except calories. When I was a child in the '40s and '50s, orange juice was a rare treat and we were strictly limited to one 4 oz glass at most a couple of times per week. Today, people think nothing of drinking a 20 oz serving of fruit juice daily which contains 50-60 grams of sugar (~15 teaspoonsful), delicious fresh fruits are available year round, and high fructose corn syrup and/or sucrose are now used in the majority of commercial foods. "Sport" drinks didn't exist when I was young, and nobody was putting sugar in pizza or lasagna then, either. The rapid increase in high fructose corn syrup and fruit consumption during the '80s is now manifesting itself in poorer health for most. The point is that something in the American diet is screwing us up royally; and sugar consumption, and fructose in particular, appears to me to be the culprit. Actually, I wanted to put even more about the research in the article but haven't had time.

"it's slower to digest therefore the pancreatic function is not overloaded"

In actuality, fructose causes insulin resistance (a component of type II diabetes). This causes glucose levels to alway be higher than normal, increases the height of postprandial glucose peaks, and increases the glycation damage glucose causes. This is in addition to the seriously increased glycation activity of fructose, which sometimes predominates in cataracts. This is an indicator of lifetime glycation damage since the lens crystalline proteins are so long-lived.

"because fructose (the sugar of fruits in most cases) has been arround humans and ancestors for million of years... the human body is very much acclimated to fructose consumption, and fructose can be considered for historical reasons to be the main physiological sugar for oral consumption."

This statement is rather misleading. Glucose is the main sugar, and the primary fuel for our bodies. Fructose may be absent from the blood stream, but glucose is always there or you would be dead. Almost all fruits we consume today are modern cultivars with very much higher sugar content than the proto-fruits they were developed from and that we were evolved to eat. Think of it as crabapples vs Fuji appples. Any named varietal (Bartlett pears, Bing cherries, etc) is higher in sugar content than it's forebears. And, don't forget that 50% of sucrose is fructose. Free fructose is also found in fruits. Humans are adapted to eat fructose only in small quantities and it is rejected by the gut if glucose is not present.

- - I disagree about today's fruit having much higher sugar content. For example, the red delicious apple has been developed to look good... not necessarily to taste good. Fruit that is picked and eaten directly from the tree is also likely to be sweeter than fruit that's been sitting at the grocery store/factory for weeks. Finally, fruits in tropical countries are amazingly sweet and I would bet you that they were also plentiful and easily available. Think of mangoes and papayas, for instance. And if you really think about it, how much longer have fruit (fructose) been around compared to sugar from sugar cane or beets?

Please sign comments. --Rhombus 16:45, 14 July 2007 (UTC)

The lengthy metabolic pathway is one example; it is digested through the liver like a toxin. When fructose finally reaches the gluconeogenesis stage, it can go to glucose, glycogen, cholesterol, or lipids. It preferentially goes to cholesterol. Reduction of fructose consumption typically lowers blood cholesterol significantly with no other changes. My personal cholesterol went from 235 mg/dl to 180, a drop of about 50 points, in 18 months.

- - I would be curious if fructose consumption was all you reduced or if you reduced consumption of other foods as well. Also, since having a high HDL is actually good for you, I'm curious to know what your HDL/LDL ratio was before and after reduction of fructose, i.e. total cholesterol levels doesn't really tell us much.

The advent of high fructose corn syrup in the late '60s/early '70s as the lowest cost sweetener per dollar became a significant change in the American diet as it was widely implemented into commercial foods through the '80s. With the expected 15 year delay, for the results to start showing up, we now are seeing the detrimental health results of that increase in fructose consumption. Some public health experts are now concerned about a possible reduction in American average lifespan in spite of modern medical treatment advances.

A short list of recommended references:

Elliott SS, Keim NL, Stern JS, Teff K, Havel PJ. Fructose, weight gain, and the insulin resistance syndrome. Am J Clin Nutr 2002;76:911–22.[2]
International Obesity Task Force Website. August 2002: Internet: http://www.iotf.org/media/syrup.htm
Teff K, Elliott S, Tschoep M, et al. Consuming high fructose meals reduces 24 hour plasma insulin and leptin concentrations, does not suppress circulating ghrelin, and increases postprandial and fasting triglycerides in women. Diabetes 2002;51(suppl):A408 (abstr).
Dills WL Jr. Protein fructosylation: fructose and the Maillard reaction. Am J Clin Nutr 1993;58(suppl):779S–87S.
Bell RC, Carlson JC, Storr KC, Herbert K, Sivak J. High-fructose feeding of streptozotocin-diabetic rats is associated with increased cataract formation and increased oxidative stress in the kidney. Br J Nutr 2000;84:575–82.
Levi B, Werman MJ. Long-term fructose consumption accelerates glycation and several age-related variables in male rats. J Nutr 1998; 128:1442–9.
Cohen JC, Schall R. Reassessing the effects of simple carbohydrates on the serum triglyceride responses to fat meals. Am J Clin Nutr 1988;48:1031–4.
Crapo PA, Kolterman OG, Henry RR. Metabolic consequence of two-week fructose feeding in diabetic subjects. Diabetes Care 1986; 9:111–9.
Bantle JP, Raatz SK, Thomas W, Georgopoulos A. Effects of dietary fructose on plasma lipids in healthy subjects. Am J Clin Nutr 2000; 72:1128–34.
Abraha A, Humphreys SM, Clark ML, Matthews DR, Frayn KN. Acute effect of fructose on postprandial lipaemia in diabetic and nondiabetic subjects. Br J Nutr 1998;80:169–75.
Jeppesen J, Chen YI, Zhou MY, Schaaf P, Coulston A, Reaven GM. Postprandial triglyceride and retinyl ester responses to oral fat: effects of fructose. Am J Clin Nutr 1995;61:787–91.
Havel PJ, Elliott S, Keim NL, Krauss RM, Teff K. Short-term and long-term consumption of high fructose, but not high glucose, diets increases postprandial triglycerides and apo-lipoprotein-B in women. J Invest Med 2003;52(suppl):S163 (abstr).

There are some traps in reading the literature:

glycosylation and glycation are often confused or used imprecisely. You must read syntax to determine what they really mean.
Corn syrup sometimes means high fructose corn syrup and sometimes plain old non-fructose corn syrup
Many early fructose-related studies used improper assay techniques for fructose vs glucose glycations and glycosylations that were off by up to several orders of magnitude. You must be aware which assay techniques are accurate and read the article to determine which were used. Also, often, no distinction between glucose glycations and fuctose glycations are made.

At the risk of sounding like a broken record... references, please. --Rhombus 16:45, 14 July 2007 (UTC)

--Jwanderson 07:30, 23 November 2005 (UTC)jwanderson

What do you mean that some people react badly to fructose? -Unsigned/undated

Full blown misguided views on health effects

I added a NPOV warning for the following reasons:

Full blown misguided studies/articles about health effects: Why would fructose cause obesity if it's slower to digest than sacharose and also more sweeter for less calories, and also les likely to drive any addiction, the study about obesity is absolutly ridiculous and should ne withdrawn from that page! And the other healt effect can be submited to the same considerations!

More considerations about health effect of fructose may be described as detrimental by the sugar industry because it makes huge profit on the addictive properties of glucose and sucrose that are often detrimental to the health because of poor mineral content, trigering insuline rush through hypo/hyper glycemia vicious cycles! In reallity fructose is much healtier than glucose and sucrose because:

it's slower to digest therefore the pancreatic function is not overloaded, as a side effect it's very much tolerated by diabetic people!
because it's often absorbed with fruits it's associated with many highly valuable nutriments!
because fructose (the sugar of fruits in most cases) has been arround humans and ancestors for million of years (we know something about roots sugar just from industrial time) the human body is very much acclimated to fructose consumption, and fructose can be considered for historical reasons to be the main physiological sugar for oral consumption.
nowdays we eat about 100 times more sugar than our ancestors 200 years ago!

We recall here that huge profit are made from addictive substances, sucrose/glucose can easily become addictive with many consequences : diabetis, tooth decay, probably hyper-activity and some burst of violence actually the main recommendation for glucose absorbtion is before an intense burst of physical activity! Not everyday for most people.

A note on "food industry conspiracy" theories: two or three decades ago most of US food industry switched from sucrose (beet or cane sugar) to HFCS (high fructose corn syrup) wherever it could, for purely economic reasons. So, today US food industry has incentive to suppress, rather than invent, evidence for link between high fructose consumption and obesity. See, for example, this little article in "The Economist". --bonzi 17:55, 19 May 2007 (UTC)

Just because you don't agree with the article, it doesn't mean that it is biased. The linked study does not appear unscientific to me. If indeed a diet high in fructose leads to obesity in laboratory animals, and the same effect is considered likely in humans, then this is certainly worth mentioning in Wikipedia. --221.249.13.34 05:20, 22 September 2005 (UTC)

Agree with previous poster, just because you don't agree doesn't mean it's not true! And as for that posted study, there actually was *another* one done with mice conducted by the University of Cincinnati just recently that apparently also supported the view that fructose for some reason fosters fat creation. Matter of fact it was all over the news here at one point. http://cincinnati.bizjournals.com/cincinnati/stories/2005/07/25/daily43.html <-is the first thing I've found about it. I actually with some effort managed to track down the article where they published their findings, but it's locked down behind one of those lame 'you need a subscription to view this article' sites. The study apparently compared mice drinking water, a sucrose sweetened commercial drink, and a mix of water and fructose. They apparently were rather suprised that both the soft drink and fructose water drinking mice actually ate less food than the mice with water, and thus the caloric intake ended up about the same. However, the fructose water mice gained a signifigant amount of weight versus the soft drink and water mice, apparently. From things I've read, they apparently also suggested that the recent obesity epidemic was caused by the introduction of 'high fructose corn syrup' to drinks. The industry didn't like that, and from what I've read I gather they attacked the study methods as well as the fact that the 'fructose water' used pure fructose, whereas they do not. That's two studies now that indiciate that fructose *by itself* anyway can cause increased fat creation versus normal sucrose. The best thing in this instance is to remember to step back and look at all sides. The article already mentions the effects with diabetics, and in facts states that it is 'hypothesized' that it *might* cause obesity. I really, really don't see any NPOV Problems with this article, tell the truth. And the article *also* mentions that fructose is generally found 'in combination with sucrose and glucose.' I've heard, though not personally seen, that studies have been done which show that the addition of glucose vastly reduced this effect. However, the article is about fructose itself, and as the views you oppose are presented as mere supposition, I don't understand how there's a NPOV Problem. -Graptor

I'm going to remove the NPOV dispute, since I think it's based on ignorance. Aside from the fact that there are many well-done studies on the relationship between fructose and obesity, the OP is clearly misinformed about fructose, since, in fact, it is the major sugar used in foods today (in the form of High Fructose Corn Syrup, HFC) by the "sugar industry" s/he lambasts. Graft 20:50, 30 September 2005 (UTC)

I'm going to re-remove the NPOV dispute, as it seems to have magically reappeared without comment. -- Canar 20:49, 31 July 2007 (UTC)

Isn't glucose converted to fructose in glycolysis? So don't all human cells (actually all cells) use fructose, and not just those of the liver?

Hi, No. It is not converted to fructose. It is instead converted to forms of fructose phosphate (fructose-6-phosphate, then fructose-1,6-bisphosphate) in gluconeogenesis. Although the name fructose is there, these are structurally different from fructose alone. According to the biochemistry books that I have read (check them out at PubMed), only the liver and kidney can break down fructose. —Preceding unsigned comment added by 129.7.111.42 (talk) 22:10, 1 October 2008 (UTC)

2004

Structures of L Forms

I have removed these structures from the article because they seem incorrect to me. They are not mirror images of the α-D and β-D forms. The two "front-most" hydroxyls need to be "flipped". I think that the strucures shown are not fructose at all, but some other ketohexose.

Supposed α-L-Fructose Supposed β-L-Fructose

Oops, forgot to sign. Josh Cherry 00:23, 2 Jul 2004 (UTC)

I'm sorry about that, and taking a long time to fix it. I've updated the images, can they be included now? [[User:Sverdrup|❝Sverdrup❞]] 08:16, 8 Sep 2004 (UTC)

They look right to me now. Josh Cherry 01:18, 9 Sep 2004 (UTC)

These graphics are still incorrect. In each graphic, where ever CH3 or H3C is found, it should be CH2 or H2C respectively. Thank you for placing these graphics online.... but they need to be accurate before they are borrowed and end up on websites and student papers all over the world. User: Don DeWitt 1 Nov 2004

The same problem exists for the D-isomers. I have created revised images in Photoshop but I do not know how to upload them. The original author may wish to make these corrections and obviously knows how to do it. User: Don DeWitt 1 Nov 2004

One last thought. It would be very helpful if the carbons were numbered in all the graphics. User: Don DeWitt 1 Nov 2004

Only the ring-carbons? -69.47.186.226 07:11, 17 May 2007 (UTC)

FROM ANONYMOUS - Fructose-Sweetened Drinks Associated with Adverse Health Effects Results of a recently completed study have confirmed that drinks sweetened with fructose increases levels of bad cholesterol, or LDL cholesterol, and triglycerides, both of which are known risk factors for cardiovascular disease.

The randomized, double-blind study evaluated the effects of consuming soft drinks sweetened with fructose or glucose in 32 overweight participants during a 10 week period.

While both groups--those who consumed fructose and those taking glucose--gained weight, only those exposed to fructose-sweetened drinks had increases in lipids and in visceral adiposity or fatty abdominal tissue.

Additionally, the researchers at University of California Davis reported "...fasting plasma glucose and insulin levels increased and insulin sensitivity decreased in subjects consuming fructose but not in those consuming glucose."

While the study conditions were not representative of real life, they nevertheless provide important information on health risks for certain populations associated with fructose consumption when used as a beverage sweetener.

The study was published Monday, in the Journal of Clinical Investigation.

APRIL-22-09: Fructose-Sweetened Beverages Linked to Heart Risks in Overweight Patients [NY TIMES: FRUCTOSE-SWEETENED BEVERAGES LINKED TO HEART RISKS] —Preceding unsigned comment added by 167.131.0.194 (talk) 16:52, 29 April 2009 (UTC)

2005

"Fructose is a blood sugar"?

I'm a bit confused by the following sentence:

Fructose is a simple sugar (monosaccharide) found in many foods and one of the three most important blood sugars along with glucose and galactose.

According to the article about blood sugar, the term blood sugar is only used to refer to the glycose levels in the blood. It's true that fructose and galactose can be converted into glycose, but does that really make them blood sugars themselves? If not, I think the above sentence should be rewritten, but if that's really the case, I would say the blood sugar article needs an update. - Wintran 03:54, 19 October 2005 (UTC)

Erm... "blood sugar" as a medical term refers to glucose, which means glucose levels are used to meter the amount of sugar in the blood, but there are nevertheless other sugars present in the blood. Graft 04:09, 19 October 2005 (UTC)

Ah, I see. Do you think we can clarify this in the blood sugar article, that the term can also be used to refer to other types of less prominent sugars in the blood, and not just glucose? - Wintran 12:20, 19 October 2005 (UTC)

I'll try and clarify it. Graft 22:11, 20 October 2005 (UTC)

Thanks, looks much better now. - Wintran 00:03, 22 October 2005 (UTC)

2006

Are Fructose and Levulose different?

This is in response to a statement in a www.mercola.com/2006/feb/4/stop_marketing_sugary_cereals_to_kids.htm ^{[unreliable fringe source?]} Mercola article] where he states "CSPI has been on a campaign to lump all sugars together, claiming, wrongly, that corn-derived fructose is no different than the levulose that comes from fruit." Any idea what he's getting on about? I thought fruits had fructose, not levulose, it'd make sense if they're the same but why use different terms... is the fructose in corn syrup not levulose? -Tyciol 10:06, 7 February 2006 (UTC)

Uh. Possibly he's referring to the fact that corn syrup is mostly D-fructose whereas fruits are mostly L-fructose (levulose). I'm not even sure if this is true, it's just a hunch I have. Also I don't know whether this has any physiological implications. Graft 15:33, 7 February 2006 (UTC)

I believe that levulose is actually D-fructose. The reason that the name begins with the letter "l" is that Levulose was named using the d/l classification of Chrirality, not D/L. This is a bit confusing, see the Chirality article for an explanation of the difference between d/l vs. D/L. The isomer of fructose found in fruits will be the same the one that can be metabolized by humans (D-fructose), so the terms levulose and fructose should be synonymous in this context.

(d,l) versus D,L is only confusing because (d,l), while still widely used, is basically archaic. The (d,l) (dextrorotatory versus levorotatory) system is the exact same as the (+ -) system, and whereas d and l don't mean much to people who don't speak Latin, + and - clearly indicate the sign on the optical rotation of the molecule. Chemists really ought to use (+) and (-) exclusively.

So, in case anyone reading this thread is confused by Graft's post, dextrose (glucose) was so named because of its dextrorotatory nature, wile levulose (fructose) was so named because of its levorotatory nature. That makes glucose (+), and fructose (-). The only molecule for which it is safe to assume that (d) implies D (and (l) implies L) is glyceraldehyde: this is the molecule whose (d,l) optical rotation properties define the D and L system. Long ago, (d)-glyceraldehyde was chosen to be D-glyceraldehyde, and (l)-glyceraldehyde was chosen to be L-glyceraldehyde. All other molecules are then defined as D or L depending on which enantiomer of glyceraldehyde they resemble. This says nothing about a molecule's optical rotation (its (d,l) configuration), which must be determined experimentally. Even typing this is, at times, confusing--yet more reason why (d,l) should be abandoned in favor of the more informative and unambiguous (+,-) system.

As far as the original question goes, common usage of the words "fructose" and "levulose" almost always refers to D-fructose--so yes, in short, they are the same. L-fructose is a far less important molecule, and therefore it is always referred to by its full name. Another thing to remember is that, 99% of the time, dietary sugars are D, not L. The human body cannot metabolize L-sugars. -128.101.53.195 07:32, 24 April 2007 (UTC)

The human body cannot metabolize L-sugars. - This is NOT mentioned in the article and SHOULD BE. I got here looking up levulose, fairly certain of that fact, but the entire article does not even have the word enantiomer in it. -G (talk) 15:09, 7 October 2009 (UTC)

So, is there a difference between fructose and levulose? Is there a difference between refined fructose and natural fructose in fruits? —Preceding unsigned comment added by WWwiikkii (talk • contribs) 02:13, 27 February 2010 (UTC)

Which form is the most common?

Can anyone tell me which form is the most common? I will then use that one as the base for an info table. Ryan Jones 20:09, 4 April 2006 (UTC)

The quick answer is that the D isomer is the more common (natural) enantiomer. The tricky part is that it exists as an equillibrium mixture of open chain, pyranose and furanose forms - and each of the ring forms exist as mixtures of alpha and beta anomers. --Ed (Edgar181) 20:28, 4 April 2006 (UTC)

Well, does anyone know the equilibrium concentrations, at least of the open-chain versus furanose forms? -69.47.186.226 07:12, 17 May 2007 (UTC)

My old Introduction to Organic Chemistry (Streitweiser & Heathcock) says 'glucose exists almost entirely in the cyclic form, in solution it is in equilibrium with a minute amount of the noncyclic... form. I guess the same holds for other sugars. Ewen 07:58, 21 June 2007 (UTC)

Reference for more about metabolism

Removing the following from the article:

Articles

Carbohydrates and Increases in Obesity: Does the Type of Carbohydrate Make a Difference? Judith Wylie-Rosett [3]
For more details about fructose metabolism see: * Horn, R., [4]

May be useful when expanding the article. - Samsara (talk • contribs) 17:55, 22 April 2006 (UTC)

Fructose for the hypoglycemic?

From the article:

Fructose is often recommended for, and consumed by, people with diabetes mellitus or hypoglycemia...

Why would fructose be recommended for those with hypoglycemia? Shouldn't that be hyperglycemia? Cburnett 18:58, 12 June 2006 (UTC)

Hyper is too much, hypo is too little. Too little sugar (hypoglycemia) means you'd need more. kdepa 1 December 2006

Health effects?

I can't beleive that a natural ingredient of fruits be THAT bad for our health... Would Fructose be supposedly bad because it is either "refined" like in white sugar, or manufactured like in HFCS, and therefore it lacks the necessary enzimes that might be present in unrefined sugar and fruits? User_talk:_dhrm77 Undated

I agree, the health effects section seems very biased to me, with some unclear sources. - Wintran ^(talk) 00:43, 31 July 2006 (UTC)

What I meant to say is: Why is it that the fructose contained in fruits is good for us, but not the pure concentration that might be used as a sweetener? Is it a question of quantity? A question of missing enzimes/minerals/vitamins? Or is it something else? User_talk:_dhrm77 Undated

Well, because of the lack of neutrality in this article it feels to me like it draws the conclusion that fruits are bad, because fructose itself is bad. However, I agree with you that there are differences between fructose concentrations and natural fruits. For example, most (all?) fruits contain both glucose and fructose, so they aren't subject to the absorbation problems mentioned as a negative health effect.

Regarding obesity problems it definitely seems more a quantity problem than quality. Overeating can be caused by any type of food and I've yet to see a research showing a clear connection between fructose and obesity that cannot be seen in other sugars that contain equal amounts of calories. - Wintran ^(talk) 13:35, 31 July 2006 (UTC)

Nope. Take two populations and feed them equal number of calories, but one population eats foods sweetened with sugar and the other eats foods sweeteneed with high fructose corn syrup. The population that eats foods sweetened with high fructose corn syrup will suffer from much insulin resistance significantly more than the population eating foods sweetned with sugar. If it was just quantity, you would see no such effect. 65.68.190.251 10:24, 15 July 2007 (UTC)

That's interesting, do you have a source for that claim? Currently, this article states the opposite, though I cannot find the research it's referencing to:

"Studies that have compared high fructose corn syrup (an ingredient in soft drinks sold in the US) to sucrose (common cane sugar) find that they have essentially identical physiological effects. For instance, Melanson et al (2006), studied the effects of HFCS and sucrose sweetened drinks on blood glucose, insulin, leptin, and ghrelin levels. They found no significant differences in any of these parameters."

- Wintran ^(talk) 14:35, 15 July 2007 (UTC)

Please get over the idea that anything natural is also good for you or even safe! Uranium is a naturally-occurring substance. Want to eat some?

Umm...natural behavior probably is good for you. That's the point of natural selection. Compare the number of species whose diet includes uranium to the number of species whose diet includes fruit. -69.47.186.226 07:15, 17 May 2007 (UTC)

That's beside the point dhrm77 was trying to make. Fruits have always been stereotyped as a healthy food, one that should be part of a healthy diet. It's better not to go off on tangents here.. Litanss

Could someone possibly this up for neutrality using the sources below?

I believe the negative criticism towards fructose is a result of the growing apprehension surrounding HFCS. HFCS and fructose aren't the same thing at all, and they are very often confused with each other. The GI of HFCS is much higher then fructose (because it contains other sugars), and fructose has the lowest GI of any sugar, as stated in the article. This makes fructose a commonly preferred sweetener in most weight loss diets. Someone should add information about the positive effects of fructose - I'm including links providing them below:

(explains differences between HFCS and Fructose itself.) In addition, the following is an excerpt from the HFCS wiki:

"High fructose corn syrup is actually not naturally occurring fructose. It's usually derived from sucrose using a chemical process and is in fact much closer chemically to sucrose then it is naturally occurring fructose. It's also only been around since the late 1950s having been invented in 1957" -Litanss 07:47, 13 June 2007 (UTC)

fructose free diet

Is it posible to have a fructose free diet... ?

You mean as a monosaccaride or completely absent i.e. no sucrose too? David D. (Talk) 20:11, 12 September 2006 (UTC)

Yes, I maintain an almost fructose free diet. Occasional fruits, especially berries, have very little fructose in them compared to the general public's main sources of fructose, which I have edited on the main page. I believe the actual need for fruits in the diet is way overblown anyways. JaredBond (talk) 06:36, 8 February 2010 (UTC)

Excessive

Some demonizing in the "Health Effects" section, comparatively to other sugars gives a flawed and excessive view of the negative effects.A non-biased revision would be in order.-Thomas —Preceding unsigned comment added by Tdonner (talk • contribs)

im no expert, or anything like it, and i dont know much about the subject either to be honest. But, that article did look like it was focused a lot on the negitive effects of the fructose.

I think listing ALL health effects of fructose in the "Health Effects" section would be beneficial. i.e. saying what will happen if no fructose is present in the diet, how it differs from other sugars, etc. Not just the negative health effects of overconsumption.

Why do you only present the furanose form?

Why do you only present the pyranose form of fructose with this page? It's a common trend among organic and biochemistry texts to exclude the pyranose form of fructose. The funny thing is, the pyranose form is lower in energy, and also the major form of fructose that is found in nature. Here are a few references in case you're interested. You really should include it in your discussion that you've sweated so much over.

P. Dais, A.S. Perlin, Car Res, 169 (1987) 159-169 W. Funcke, C. Vonn Sonntag, C. Triantaphylides, Car Res, 75 (1979) 305-309 C. Luu, A.M. Meffrov-Biget, D.V. Luu, Car Res, 81 (1980) 213-223 J. Baran, H. Ratajczak, E.T.G. Lutz, N. Verhaugh, H.J. Luinge, J.H. van der Maas, J. Mol Struc, 326 (1994) 109-122 S. Söderholm, Y. H. Roos, N. Meinander, M. Hotokka, J. Raman Spec, 30 (1999) 1009-1018 J.A. Kanters, G. Roelofsen, B.P. Alblas, I. Meinders, Acta Cryst, B33 (1977) 665-672 S. Takagi, G.A. Jeffrey, Acta Cryst, B33 (1977) 3510-3515 A.D. French, J Plant Physiol, 134 (1989) 125-136 A.D. French, V. Tran, Biopoly, 29 (1990) 1599-1611 S. Cerrini, V.M. Coiro, D. Lamba, Car Res, 147 (1986) 183-190 —Preceding unsigned comment added by 137.190.76.112 (talk • contribs)

Maybe you could add something appropriate? This is no ones article but a collbaorative project David D. (Talk) 13:22, 8 October 2006 (UTC)

Fruits a bad rep?

This article gives fruits a bad rep. I have never heard of anyone having a destroyed liver on eating too many apples...and here this article states that rats have cirrhosis by eating too much fructose? BS. The article even fails to mention that, even if it is true that fructose does damage, fruits have a lot of phytochemicals and antioxidants that offsets the effects of pure fructose (which cannot be absorbed on its own). Either the bias is there or the one who made this article didn't do enough adequete research. Bellybutton Lint 10:51, 11 November 2006 (UTC)

The difference is the amount of fructose. There is a table included on the main page. As you can see, fruits do not have as much fructose as something sweetened with sugar. JaredBond (talk) 06:39, 8 February 2010 (UTC)

2007

Fructose: not fruit

I think this article is right on. The article is seems to be talking about fructose in and of itself not in fruits. What I mean is this. The article is not saying fruits are bad for you because their primary sugar is fructose, because there are obviously a lot of great benefits to fruit. Fructose itself, is not the greatest for you and this is based primarily on research into very concentrated forms of the sugar, mainly, high-fructose corn syrup, which in my opinion is what the article is talking about when it bad mouths fructose. They should make that distinction though. They probably know that most people get a lot more fructose from high fructose corn syrup than they do from fruit.

That, and it's not like fruits only contain fructose sugar. Glucose is certainly present in large quantities. -69.47.186.226 07:16, 17 May 2007 (UTC)

I feel fruits contain glucose,sucrose & fructose in varied amounts along with mainly pleasant flavors which tempt one to over eat; a diabetic takes in only known(measured) amt of fructose which doesn't have a flavor. P.Balagurunathan, Bangalore

Agree with this article

Actually I would say fruit is the worse, especially sweet fruit. It took me a long time to figure out it wasnt the wheat or dairy that was making me feel ill or hypoglycemic, but the oranges and raisins. Since getting rid of high fructose foods (getting rid of hfcs soda alone made little difference), I'm feeling much better. My doctor cannot believe the radical change in my lab numbers. No big loss - vegetables are far more nutritious than fruits anyway.

Maybe there is more to the apple in the garden of eden story than meets the eye.

1. Please sign your comments. 2. Raisins are high in glucose. Try eating some fruit that's less sweet. I suspect you seek out the really sweet fruit because you have cravings, which would be a symptom of your hypoglycemia. --Rhombus 16:48, 14 July 2007 (UTC)

-Actually, as far as fructose containing foods go, raisins are high in fructose: Fructose malabsorption as are beets, honey, dates, sweet potatoes, figs etc

I do get sugar cravings like everyone I suppose however if I satisfy them with a candy bar or even hfcs soda (both of which I avoid), I get no blood sugar problem in terms of feeling like I'm about to die. If I were to have even a speck of honey or a date, I would get strong hypoglycemic symtoms. For me hfcs and sucrose soda gives me no ill effect (but I avoid them). If I were to have a "natural soda" sweetened with fructose (not hfcs), I would feel very bad. For me, it seems if the food has a high concentration of natural fructose, I get hypoglycemia (shakes, confusion, extreme fatigue etc). Tens67 16:40, 1 August 2007 (UTC)

Thanks for the anecdote, fruits give you a belly ache.

- Fruits don't give me a belly ache - they give me profound fatigue, hypoglycemia and an out of control appetite.

I like where you are going with the Eden story though; it wasn't about trust and obedience, God was just looking out for Adam and Eve's blood sugar levels. Vegetables are far more nutritious? Is that a fact? As far as nutritional value goes, I would put pomegranates, bannanas, and blueberries against cucumbers, corn, and soybeans any day. Niubrad 23:24, 28 February 2007 (UTC)

You just compared fruit to fruit. :-) -- General Wesc 19:00, 29 April

Corn is a fruit? That's shocking. -69.47.186.226 07:20, 17 May 2007 (UTC)

Biologically speaking, yes. But that's hair-splitting, I guess. --Slashme 07:27, 17 May 2007 (UTC)

Yeah and try comparing any of those teeth rotters to something like collard greens or heck even potatoes.

Are you seriously claiming that potatoes are a relatively nutrient-rich vegetable? -69.47.186.226 07:20, 17 May 2007 (UTC)

To be fair: does starch count as a nutrient? Nonagonal Spider 04:14, 4 November 2007 (UTC)

That's another thing with fructose - it destroys teeth and gums very quickly. Just visit a group of fruitarians or let a baby sit with apple juice in its bottle overnight to see this effect.

It's All How you Look At It

I believe that you should have things in moderation. It's not good to have too much or too little of anything considered as healthy foods. If you you eat too many carrots, your skin tone turns orange. If you don't consume enough dairy products, your bones become weak. Fruits have their good qualities and their bad qualities, so balance your consumption to make up for the negative aspects, and you'll be right as rain. -Unsigned/dated

Effects of Fructose vs Fruit

Presumably the article pertains to pure fructose, and is not a discussion of the effects of fruit. It would be very unlikely that by eating fruits one could develop obesity or insulin resistance. Because fruits contain a plethora of disease-fighting compounds, including ones that decrease the risk of obesity, insulin resistance, heart disease, constipation, age-related macular degeneration, etc, the American Heart Association et al is always recommending eating more of them! This article needs to strengthen the distinction between fructose and fructose consumed in the form of fruit. The chemical is the same, but the long-term effects (and levels of exposure) are far different. -Muugokszhiion 18:38, 3 March 2007 (UTC)

Additionally it is very rare for anyone to eat pure fructose. It is a sweetener used in other foods. Often it only makes up a portion of sugar contained in foods. Any study that doesn't directly deal with the actual eating habits of humans could be considered irrelevant. All animals metabolize foods differently and have different body compositions including fat reserves. Many human foods will make other animals obese or sick. In the same way the foods eaten by other animals may cause obesity or other illnesses in humans. Often scientific findings are based on statistical information and customize experiments, both of which can be manipulated to provide a desired result. This is why there are so many conflicting studies on all sorts of subject matter. Science is an ongoing study of the world around us and ever evolving. Science has a tradition of proving previous findings wrongs. What is found to be conclusive now, is often disproved tomorrow.

One certainty is most studies on this subject are funded for economic reasons. Often the studies are funded by people who sell fructose or their competitors. In addition many studies are used to sell books or push ideologies. Only by taking a careful look at all the scientific findings and the motivations behind all the studies can we make any sort of valid assessment of the health affects of Fructose. I assume most of us don't have the time, the scientific expertise or access to all the information to form any relevant opinions.

To that end lets all relax a little about the health effects of Fructose. It's not toxic, it's been around for forever, there is no conclusive findings showing fructose in any of it's form has caused any illnesses in humans. What one studies proves another study disproves. As many studies tout the health benefits of Fructose as raged about the possible downside of fructose. Lets chill with the agenda driven contributions. This article is about fructose a naturally existing compound that we have eaten since early man. Yes it is a component of processed food, but then again I have yet to find a Tofu tree, a cheese plant of a river of beer. We all eat processed foods everyday, it is one of the reasons we live so long and do so much. Do you really want to spend all day walking through the woods eating berries and grubs?

I have nothing wrong with taking a critical look at any subject matter, but this is not a place to push any agenda. If you want to preach from a soap box about the evils of fructose, get a blog or join one of the many online forums.Mantion 00:17, 20 April 2007 (UTC)

Major mistake: Fructose is NOT a reducing sugar

Glucose + DNS -> Gluconic Acid + reduced DNS

Fructose + DNS -> Fructose + DNS

Glucose has an aldehyde group and, as such, it can be oxidized to a carboxyl group. Fructose however, is a ketone, and ketones just don't oxidize, no matter how hard you try.

[Edit: The articles here confused me.. They all say that fructose is a reducing sugar, but that goes against all that I've learned at the University and from books. I researched a little more on the web and I came up with an explanation for this. Ketones can be oxidized but they are destroyed in the process.

"Because ketones don't have that particular hydrogen atom, they are resistant to oxidation. Only very strong oxidising agents like potassium manganate(VII) solution (potassium permanganate solution) oxidise ketones - and they do it in a destructive way, breaking carbon-carbon bonds." http://members.aol.com/logan20/ald_rx.html

In organic systems, such as our body, from what I know, their oxidation is close to impossible.

Please correct me if I'm wrong! I'll ask my teachers this on Monday and will correct all the pages so that it is acurate.

]

Best regards! Jp-rodrigues 15:55, 25 March 2007 (UTC)

Hmm I came on here to try and find out the saem kind of thing, why *is* fructose a reducing sugar, all iv read is that 'fructose is also a reducing sugar which is surprising' or words to that effect. I can also confirm it is reducing as I have tested it myself.

ah found something, maybe I should add it, im new to this though...

Fructose can also act as a reducing sugar, even though it has a ketone group instead of an aldehyde group. Under basic conditions, the fructose molecules can, essentially, have the location of the carbonyl bond switched to convert them into a glucose molecule. This occurs in a number of steps involving removing hydrogens from the #1-C and its oxygen and moving them to the #2-C and its oxygen. http://dl.clackamas.edu/ch106-07/reducing.htm

hi! quick answer: a ketose can be isomerized to an aldose (catalyzed by a base), which can then be easily oxidized. here's how it (roughly) works--the alpha hydrogen off the carbonyl is attacked by the base, resulting in a resonance form with the negative charge shared between the alpha carbon and the oxygen. the oxygen attacks a neighboring hydrogen from a hydroxyl group, which then moves the negative charge to the C1 oxygen. as the carbonyl reforms on C1, the double bond between C1 and C2 that formed as a resonance structure in the first step attacks a hydrogen in the aqueous solution, resulting in the aldose. oxidation then proceeds as normal.

128.180.231.188 (talk) 13:59, 9 April 2008 (UTC) vkkim

Good Luck buddy, you will need it. You seem to think that logic, scientific reasoning and a complete understanding of the subject matter will help you fix this article. Unfortunately you are wrong. No matter how right you are, or how hard you try, you are up against a force of ignorance you will never be able to defeat. I hope I am wrong, but I doubt it. If you spent your entire life studying the subject and argue your case till your dieing breath, you will accomplish very little. It seems that one political view has decided fructose as bad. I have no idea how or why this happened, but that is their view and they are dead set to protect it. The reader must come away with the understanding that fructose is bad. That is the goal of this article. It is sad, I think that we should take a fair look at it, but that won't happen here. Good luck, fight the good fight. If you start getting insulted just know that you are right and give up. They will just ignore you or insult you more.Mantion 22:38, 17 April 2007 (UTC)

Another major mistake is that pure fructose has a GI of about 70, not 20 as stated in the GI tables

GI only applies to high starch foods.

The basic GI definition is chemically incorrect. This is because the body blood glucose response is "standardized" with 50g of glucose, while the GI Researchers use 50g of Digestible CARBOHYDRATE as a reference quantity. Although all simple sugars are isomers, each have separate chemical properties. This is illustrated with pure fructose. In a study carried out by Hughes- http://www.ajcn.org/cgi/reprint/49/4/658

Glycemic responses in insulin-dependent diabetic patients: effect of food composition13 Thomas A Hughes, Joycelyn Atchison, Jane B Haze/rig, and Buns R Boshell

ABSTRACT This study examined the hypothesis that the glucose component of food and not the total carbohydrate is the major determinant of the glycemic response in patients with insulin-dependent diabetes mellitus. Patients were given glucose alone, fructose alone, glucose + fructose, lactose, and glucose + fat + protein. Fructose given alone increased the blood glucose almost as much as a similar amount of glucose (78% of the glucose-alone area, p < 0.05) erniemac@comcen.com.au [edit]

- Fructose a reducing sugar or not? As always this is a question of conditions: Under the normal conditions used to assess reducing sugars, ie)Cu (Benedict's or Fehlings) or Ag (Tollens) oxidations, fructose will give a negative test because as stated above it does not contain an C1 aldehyde functional group but rather a C2 ketone and the oxidative potential (Eo) of these metals is sufficient only to oxidise aldehydes and not ketones or alcohols. Under vigorous conditions, oxidation can be achieved but rather than oxidising the C2 ketone, cleavage occurs between adjacent diol groups to cleave the carbohydrate backbone giving two acidic residues at the site of cleavage (is Mn, Pb etc). Just to really confuse things fructose can also undergo an isomerisation process in which under basic conditions (dil NaOH) the C2 ketone is transposed to a C1 aldehyde via a enediol intermediate (the oxidation state remains the same) to generate glucose which is a reducing sugar. This reaction (glucose<->fructose)happens under physiological conditions although to a very small extent as the majority of the fructose or glucose exists in the cyclic form (~99%)which is resistant to the isomerisation process. So if the reducing sugar reaction is conducted on fructose under basic conditions then the slow isomerisation of fructose to glucose will eventually give a positive result which probably accounts for the confusion. To summerise: fructose is a non-reducing sugar under most conditions used to assess reducing sugars (ie Benedicts, Fehlings, Tollens) AndrewMT 07:03, 4 July 2007 (UTC)

And aren't Benedict's, Tollens' reagents and Fehling's solution alkaline? The first one contains sodium salts (partial hydrolysis), the second needs NaOH + NH3 to prepair, and the third - also NaOH. I have two organic chemistry books at home that claim it to be so. A nonreducing sugar must have an acetal group which is stable in alkalis, e.g. sucrose Mjackas (talk) 16:36, 6 January 2008 (UTC)

Article is a mess

This article is in dire need of attention from somebody who knows what he or she is talking about. It's poorly referenced, it makes all kinds of assertions which drip bias, and leaves me no more informed -- even about where to find reliable information -- than I was to begin with. It doesn't meet the standard of quality I've come to expect from Wikipedia. Is there anyone with a background in cellular and molecular biology who can help us clean it up? --Rhombus 16:51, 14 July 2007 (UTC)

I agree!

There are many reiterated statements in this article and there is no coherency to any of the paragraphs! -Unsigned/dated

Stick to the FACTS and Remove hypothetical

I find sentences like Fructose has been hypothesized to... to be highly misleading, and since they lack substantive proof, I find that material like that has no place in the bulk of the article. It has its place in the Talk section, or at a Scientific Conference on Fructose, but not in an Encyclopedia. Stick to the Facts. If no opposition is voiced here, I will delete hypothetical discussions from this article. Ricardo Lugo 19:13, 24 July 2007 (UTC)

"Eating fructose as compared to glucose results in lower circulating insulin levels, leptin, and ghrelin levels postprandially.[18]" don't you mean to say the inverse? -Unsigned/Undated

Is it worth to buy fructose?

I've been using fructose for a while. I read this article and I started to ponder. At this point I would like to know if there is any solid and positive thing that can be said about fructose. This article says that fructose is cheaper than sucrose but this is not true everywhere. In Italy, which is where I live at the moment, fructose is way more expensive. This article also says that fructose can cause obesity. I take that as a possibility without necessarily complaining about it. I am starting to think that fructose, after all, is just too expensive and doesn't give me any marginal advantage over sucrose. Does any expert on the subject have any comment on this? ICE77 —Preceding unsigned comment added by 84.222.102.230 (talk) 18:36, 2 October 2007 (UTC)

I'm not an expert, but I can't see why it'd be worth it to spend extra money on fructose. It's a sugar, just as sucrose is, and there's nothing particularly beneficial about it. Litanss (talk) 04:31, 22 February 2008 (UTC)

That's not completely true. There are several reasons why to use it, mainly because it's more sweet and thus you need less of it (less calories) and it also has different physical properties. It might be useful in some cases. 80.178.114.234 (talk) 09:24, 3 July 2008 (UTC)

Steps to improve this?

It seems the recent consensus is that this article needs quite a bit of cleanup. I will volunteer some of time and knowledge as a biochemist to get things pointed in the right direction.

First, I think it should follow the layout of similar biochemistry pages on saccharides such as the glucose or sucrose page.

I think "Health Effects" as a section title sets up the bias that this macro nutrient is somehow different or more dangerous than other common macro nutrients. I think "In Human Nutrition" like the sucrose page is more proper.

IMO, I think the "Health Effects" section needs to be scrapped and rewritten. I did a reference check on some assertions that sounded fishy, e.g. the chelation of chromium business. The article does not back that claim up and is not a proper primary reference for such a claim. I believe a full reference check is in order to make sure that they do in fact specifically substantiate the claims made and aren't talking about high sugar diets in general or studies on people with metabolic impairment. I'll also keep an eye out for proper primary references.

I can cook up some proper chemdraw figures and 3d ball and stick model images.

Also, I would love to work with any professional science writers/editors on cleaning up the style. Casey.charvet 07:19, 5 November 2007 (UTC)

Just to tack on a little more. I have begun rewriting this article from the beginning. From start to finish, it is largely inaccurate. I have compared the latest studies and the information from several cell biology, medical physiology, and biochemistry books (all recent editions, none older than 5 years) and this article and I am astounded. I expect to have a draft ready in two weeks and a final version ready to go the week after that.

Here I summarise the major factual errors of the article. References will be provided in final version or upon request:

"and is one of the three most important blood sugars along with glucose and galactose." I take issue with this statement because in the statement itself there is no grounds for importance. Glucose is the only major sugar present in the blood and is the only one actively regulated by the human body. Fructose is a sugar, and along with galactose constitutes up to 20% of dietary carbohydrate intake, the rest being glucose. If somebody gives me some grounds for defining it's importance in the diet, I'd be interested to read the literature. Should be moved to a section "In Human Nutrition"

"a disaccharide consisting of glucose and fructose that is broken down by glycoside hydrolase enzymes during digestion" this is ok. Should mention sucrase, the specific family glycoside hydrolases. Should be moved to human nutrition.

"Fructose is often recommended for, and consumed by, people with diabetes mellitus or hypoglycemia, because it has a very low glycemic index (GI) relative to cane sugar (sucrose)." Who recommends? Where are these guidelines published? Is it for both types of DM? What research is it based on? What does "consumed by" mean? Don't most people consume fructose? What percentage of the daily caloric/energy intake comes from fructose in people w/ DM and hypoglycemia versus people w/out? Who did this research and where is it published? I'm thinking very little about diabetes belongs in this article unless I can find some research that links diabetes to fructose in relevant manner.

"However, this benefit is tempered by concern that fructose may have an adverse effect on plasma lipid and uric acid levels" That's an interesting statement. The American Diabetes Association has this to say in their 2006 guidelines: "In individuals with diabetes, fructose produces a lower postprandial glucose response when it replaces sucrose or starch in the diet; however, this benefit is tempered by concern that fructose may adversely affect plasma lipids (1). Therefore, the use of added fructose as a sweetening agent in the diabetic diet is not recommended. " Well, look at that. The middle of that sentence reads almost word for word with the wikipedia article. Maybe that (1) is a citation to wikipedia, even though citations shouldn't be direct quotes. Wouldn't you know, it's not a reference to wikipedia at all. It reference primary literature: Franz MJ, Bantle JP, Beebe CA, Brunzell JD, Chiasson JL, Garg A, Holzmeister LA, Hoogwerf B, Mayer-Davis E, Mooradian AD, Purnell JQ, Wheeler M: Evidence-based nutrition principles and recommendations for the treatment and prevention of diabetes and related complications. Diabetes Care 25:148–198, 2002, and the full text of this is freely available, no academic access required. [5] That smacks of the ugly P word so that line will have to go. I haven't looked into the uric acid bit, but this is getting heavy into diabetes research, a fascinating subject, but getting a bit off track.

"and the resulting higher blood levels of fructose can be damaging to proteins (see below)" I read the abstract from the 1988 Biochemistry paper McPherson et al. Looks like a good paper. I will pull the full text tomorrow. However, both the medical physiology and human biochemistry book I have state that there is almost no fructose circulating in the blood stream, so I have a hunch the paper is not going to link a high blood fructose level to protein damage, but perhaps a high intracellular fructose level. Would the author of the statement in this wiki article care to elaborate?

"The low GI is due to the unique and lengthy metabolic pathway of fructose, which involves phosphorylation and a multi-step enzymatic process in the liver. See health effects and glycation for further information." I will need look through the cited references or find my own to how 50g fructose compares on the GI to the reference of 50g glucose. In the lower part of the article it says 78% of glucose, which would be a GI = 78, which is hardly low. The remainder of the statement ascribes this low (or not) response to the unique and lengthy metabolic pathway fructose must take. This is further elaborated as involving phosphorylation and a multi-step enzymatic process, localized to the liver. Is the pathway unique? We would have to define the pathway first, and since this is an article on fructose, it might be beneficial to the article to describe this unique pathway in detail. Is the pathway(define it first) lengthy? How is it lengthy and lengthy relative to what? Does it take a long time, is a large volume of the cell utilized, does it involve many more steps? What is it being metabolized into? Are there multiple metabolic fates? What is the significance of it having a GI lower than glucose? What are the multiple steps, what are the enzymes, what are the intermediates? Could the low GI have something to do with slower absorption in the GI tract?

An analogous statement would be something like "Exercise is strenuous because of a unique, multi-step enzymatic process which involves phosphorylation."

This structure (the furanose) is responsible for the long metabolic pathway and high reactivity compared to glucose. My organic chem is a bit rusty. What about the structure makes it more reactive and what type of reactions is it more likely to engage in? I will have to find a reference for this.

Metabolic pathway and the liver: Fructose is metabolized almost exclusively in the liver. Glucose is also metabolized in the liver, muscles, and by almost every other cell in the body. One of the liver's jobs is to manage the glucose level in the blood. When the liver is metabolizing fructose, it can either utilize the fructose for it's own energy, or it can turn it into glucose which can then be turned into glycogen or released into the blood stream. In either case, fructose is broken down to glyceraldehyde 3-phosphate via 3 steps. For comparison, glucose destined for energy use must also be converted to glyceraldehyde 3-phosphate via 4 steps. Glyceraldehyde 3-phosphate, irrespective of its origin, may be converted to glucose via the gluconeogenisis pathway. It is in this way fructose may be converted to glucose and elevate blood glucose. I think organisms have remarkable ways to utilize the wide variety of nutritional sources encountered, this pathway is a wonderful example of that. The nature of the pathway by itself should not raise health concerns. If the pathway made something like oxalic acid and caused kidney failure like in the metabolism of ethylene glycol, then I think the pathway would raise health concerns. Casey.charvet 06:01, 7 November 2007 (UTC)

Casey Charvet, I have a lot of background and references that can save you a lot of time; but am a wiki newbie and not a good enough writer to fix this article myself. I agree it needs bringing up to standard of, say, the glucose page. I would like to work with you to help straighten this article out, and this would be better off-line. I don't know how to contact you. Please email me at anderson underscore jw at hotmail dot com. Thank you, Jwanderson 20:33, 10 November 2007 (UTC)

Support for fructose-obesity link

The following is copied from one of the opening paragraphs in a transcript of an Australian radio program called "The Health Report". The transcript can be found at http://www.abc.net.au/rn/healthreport/stories/2007/2104024.htm#transcript

"The question is whether there's stuff in our food which makes us even fatter than our calorie excess would suggest. It's about how a carbohydrate may be behaving like a dietary fat. One of the key people pushing this idea is Dr Robert Lustig who's Professor of Pediatric Endocrinology at the University of California, San Francisco." Hakim101! (talk) 02:10, 8 December 2007 (UTC)

Dr Lustig seems to negate a major part of his argument when he admits that sucrose contains just as much fructose as HFCS. Indeed, people seem to complain that HFCS is "the cause" of America's obesity problem (and hence Big Corn is to blame) and saying that things would be different if cane sugar was used instead. Well guess what? Australia has an obesity problem too, and we don't use HFCS in anything!

After acknowledging that HFCS is 55% fructose and sugar is 50% fructose, he agrees that sugar is just as much a problem as fructose. But we've known that for years. His argument then comes down to "we should eat less sugar". --Eirinn (talk) 03:32, 26 December 2007 (UTC)

2008

Terrible

This article is terrible. I've never seen such a flargant violation of NPOV except for perhaps on a few vanity pages. Someone is dead set against using fructose for some reason. I'm not a chemist by any means but I can certainly tell when someone's trying to push a point of view. Perhaps this should also be tagged as an NPOV violation. —Preceding unsigned comment added by Duskglow (talk • contribs) 00:46, 6 January 2008 (UTC)

Well, I am a chemist and I have to agree. This is certainly the worst I've seen. Unfortunately, I am not a nutritionalist, so I don't know where to begin, but the way this article reads, you would think fructose killed someone's mother. Jeremiah (talk·cont) 02:22, 10 January 2008 (UTC)

Apparently "they" think that it DID kill their mother. I agree that the "Health Effects" section is just garbage. --JD79 (talk) 20:13, 17 July 2008 (UTC)

"Confusion" About Fructose

I agree that there are some inaccurate statements in the fructose article. Carbohydrate metabolism and carbohydrates as nutrients are major areas of interest for me. Several years ago I used hours correcting and mounting a "new" fructose section. It disappeared after a few days! If you want correct information about fructose metabolism and its nutritional value you can go to: http://www.medbio.info/Horn/Time1-2/carbohydrate_metabolism_March_2007a.htm. There is a "external link" to this at the bottom of the "Fructose" page —Preceding unsigned comment added by Bob horn (talk • contribs) 12:11, 14 January 2008 (UTC)

Ghrelin

Hi, I am new to editing, but this article needs some work, so I thought I would add a quick comment. First of all, a minor quibble - when it talks about fructose causing obesity it mentions lower ghrelin levels.

    Eating fructose as compared to glucose results in     
    lower circulating insulin levels, leptin, and  
    ghrelin levels postprandially.[20] These hormones
    are implicated in the control of appetite and
    satiety, and it is hypothesized that eating lots
    of fructose could increase the likelihood of 
    weight gain.[21]

Ghrelin stimulates appetite, lower Ghrelin levels would reduce eating behavior and help decrease obesity. This is all mentioned on the wiki entry for Ghrelin if you want to double check. Maybe this discrepancy should be explained.

More importantly, my main suggestion was, can't you just add a "Recent controversy" section or something? Put all the pseudoscience in there and frame it in terms of a current debate and people will then know that the scientific community is in no way decided on the matter. Even using weasel-words "some scientists believe" would be better than the way the information is presented now. Then, in the health effects section just put information that is known to be correct. The health effects section is about 12012 lines long and kind of rambling anyway. Just my 2 cents, hope it is worth something. 216.207.146.26 (talk) 17:11, 25 April 2008 (UTC)

Hi, I have to disagree. Look again. In my humble opinion, it said that it ATTENUATES the SUPPRESSION of Ghrelin after eating (postprandially). This means that the suppression of ghrelin DECREASES and ghrelin levels go up. This in turn would mean MORE apetite. This is how I see it. —Preceding unsigned comment added by 129.7.111.42 (talk) 21:47, 1 October 2008 (UTC)

http://lowcarbdiets.about.com/od/nutrition/a/fructosedangers.htm

"Fructose ends up circumventing the normal appetite signaling system, so appetite-regulating hormones aren't triggered--and you're left feeling unsatisfied. This is probably at least part of the reason why excess fructose consumption is associated with weight gain."

http://jcem.endojournals.org/cgi/content/abstract/89/6/2963

"Previous studies indicate that leptin secretion is regulated by insulin-mediated glucose metabolism. Because fructose, unlike glucose, does not stimulate insulin secretion, we hypothesized that meals high in fructose would result in lower leptin concentrations than meals containing the same amount of glucose. " —Preceding unsigned comment added by 66.166.202.162 (talk) 18:40, 10 December 2008 (UTC)

If active transport (by GLUT5) by brain, muscles, fat cells, etc and there is no insulin (activated by fructose) therefore no active lowering of blood sugar to induce hunger; versus sucrose/glucose spike which increases insulin and absorbtion of glucose by fat cells and lowering blood sugar and leading to rebound hunger? Shjacks45 (talk) 22:37, 18 February 2010 (UTC)

Figure 2 Relative Sweetness of Sugars and Sweeteners

This article's Figure 2 graphic shows honey as having a sweetness profile that is less than that of sucrose (table sugar). It is generally recognized by cooks that when substituting honey for table sugar, slightly less honey is used volumetrically as it is considered sweeter. Wikipedia's page about Honey states "Honey is significantly sweeter than table sugar and has attractive chemical properties for baking". It seems there's an unexplained contradiction. Since cooking is one of my hobbies, having verified that honey is indeed slightly sweeter in recipes than sugar, generally requiring less volumetrically when substituting, I'm guessing that Figure 2 is factually incorrect when it gives honey a lower sweetness profile of 97 versus sugar's 100. If Figure 2 is factually correct, then it seems to contradict the sentence on wikipedia's honey page, or there is some missing information to explain the apparent contradiction, such as sweetness by mass versus volume! Would someone with the requisite knowledge care to fix this issue? 75.11.182.5 (talk) 17:47, 30 April 2008 (UTC)

I'm sure "sweetness" as a human sense is subjective. However in making simple syrup the product containing water has less volume than the original crystalline sugar. The honey page doesn't list water content of honey presumably because it varies. Shjacks45 (talk) 07:52, 19 February 2010 (UTC)

Figure 2 Relative Sweetness of Sugars and Sweeteners

This figure is factually correct; thanks for alerting me to the contradiction. The reference cited in the Honey page was incorrectly interpreted. The reference is from the Honey Board (not a scholarly reference) and states that "on a dry basis honey is 1 to 1.5 times the sweetness of sucrose (no reference given); however, honey is consumed in the liquid form, not in a dry crystalline form. In addition, the reference clearly states that liquid honey is approximately as sweet as sucrose. I have added an academic reference (Oregon State University) to both the Honey page and Figure 2 on the fructose page. As to why cooks generally use less honey (volumetrically) when substituting for sucrose; there are many differences between honey which contains free glucose (44%), free fructose (50%) and sucrose (1%) and sucrose in which the glucose and fructose are bound as a disaccharide and not free. There is also the difference in hydration and viscosity, but certainly the presence for the free monosaccharides will give very different results in terms of browning, texture, leavening, and quality, and the reduced volume may be an attempt to compensate for these differences. --Clariebh (talk) 21:59, 6 May 2008 (UTC)

WikiProject Food and drink Tagging

This article talk page was automatically added with {{WikiProject Food and drink}} banner as it falls under Category:Food or one of its subcategories. If you find this addition an error, Kindly undo the changes and update the inappropriate categories if needed. The bot was instructed to tagg these articles upon consenus from WikiProject Food and drink. You can find the related request for tagging here . Maximum and carefull attention was done to avoid any wrongly tagging any categories , but mistakes may happen... If you have concerns , please inform on the project talk page -- TinucherianBot (talk) 18:31, 3 July 2008 (UTC)

2009

serious math errors in table 1

the column headed fructose/glucose ratio is in blatant conflict with the free fructose and free glucose columns; 5.9/2.4≠2.0, 0.9/2.4≠0.7, 1.5/2.0≠0.9, etc. Gzuckier (talk) 05:20, 15 February 2009 (UTC)

Needs information on fructose synthesis in the body

I wish there was a section on the body's own synthesis of fructose. Fructose doesn't necessarily come from the diet. It can be synthesized from glucose in the body, via aldose reductase or by phosphorylation/isomerization. How much fructose can be made this way? That would affect how much it's useful to limit intake of fructose.Puffysphere (talk) 14:18, 17 August 2009 (UTC)

Needs a 3d model of fructose

This article could do with a 3d model of fructose like the glucose page has, can any one supply this? Thanks. —Preceding unsigned comment added by 69.4.140.8 (talk) 20:06, 23 August 2009 (UTC)

2010

Gout connection

I'm really surprised by the judgemental and non-scientific phrasing of the final sentence on the connection between fructose and gout. The writer refers to these concerns as "hysteria" even though a recent Lancet article found just such a connection and a simple review of the biochemical pathway will show why there is a connection. No one is saying fructose becomes urate, but rather, fructose metabolism causes a net ATP decrease compared to glucose metabolism. Fructose phosphorylation to F-1-P uses an ATP that is not directly regenerated later as in the metabolism of glucose. The left over ADP is converted to AMP. Meanwhile, there is a fall in Pi in the cell, which normally inhibits AMP Deaminase. The AMP is thus converted to IMP and then to Uric Acid. Pretty simple stuff if you understand basic biochemistry. To imply that the scientists pointing to a connection with gout are feeding hysteria is completely without merit. —Preceding unsigned comment added by 190.185.58.240 (talk) 15:09, 19 February 2010 (UTC)

Fructose as toxic as alcohol?

Statement that fructose is "nearly as toxic as alcohol" is patently ridiculous and unsupported by the reference given. It's ideology, not information. I'm removing the whole paragraph from the introduction to the article. --Steve D (talk) 14:19, 26 February 2010 (UTC)

It is quite obvious from the source that it is exactly about the topic "fructose almost as toxic as alcohole", he has a side by side comparision of the effects of alcohole and the effects of fructose, which clearly shows that the similarities. After that he goes through the biochemistry of the metabolism of alchole and fructose in the liver which yet again shows striking similarities of both effect and the metabolic process of the both. The whole presentation is about the toxicity of fructose. To claim the contrary and remove the section in an instant without at all waiting for a reply and/or opinions of others is quite disingneous. Please find sources that states fructose is not toxic and add a critisism section to present both viewpoints. Lord Metroid (talk) 01:28, 22 March 2010 (UTC)

I have removed it. It is not a peer-reviewed source. The onus is on the person adding the material to find a reliable source to back up their claim - see WP:verifiability. Cheers, --Amaher (talk) 01:39, 22 March 2010 (UTC)

In the talk, my understanding is that he's referring to fructose being as toxic as alcohol with respect to the liver. Alcohol does a lot of other stuff besides being metabolized the liver. Though I disagree with Stevedegrace's statement that it is "patently ridiculous" - we do not know what we do not know - I do agree that not only is the paragraph not supported by the source, but that even if it were supported, it's also not a WP:RS source for an (obviously) controversial claim, and I support the removal of the paragraph. Pro crast in a tor (talk) 10:21, 25 March 2010 (UTC)

Fructose posing a danger to children's health due to increased human fat and decreased sensitivity to insulin

Hi, I'm not a specialist but found the following news interesting enough to ask for the main editors of this article to consider including a sentence or a paragraph on it, considering its reliable source and the possible importance of its content to human health: Fructose sugar makes maturing human fat cells fatter, less insulin-sensitive Pmronchi (talk) 17:58, 21 June 2010 (UTC)

Comment

Rated "high" as highschool/SAT biology content. - tameeria 04:29, 9 March 2007 (UT —Preceding unsigned comment added by 114.163.224.192 (talk) 11:33, 16 February 2009 (UTC)

Molecular Structure

The display of the L and D isomers are too big for the window they appear in. When I go into edit mode they resize. I don't know how to fix it. —Preceding unsigned comment added by Jokem (talk • contribs) 20:56, 12 September 2010 (UTC)

Projection error?

There's a mismatch. The Haworth projection of the furanose form at the top of the page has an extra OH group than the furanose form in Figure 1. BrotherSulayman (talk) 20:20, 19 September 2010 (UTC)

I count 5 in both of them. Dr. Morbius (talk) 20:13, 20 September 2010 (UTC)

The figure is stereochemically correct as represented, and shows the appropriate six oxygens. However it is depicted with the hemiketal on the left rather than on the right, so that it is not adhering to the standard Haworth representation. The flip of the structure places the alpha face on top which could also cause confusion. Finally, pyranose rather than furanose form would be a more appropriate depiction of the state of free fructose, the furanoside being found in sucrose.96.54.32.44 (talk) 20:49, 6 February 2011 (UTC)

IUPAC Name

The IUPAC name of "Fructose" is not "Fructose." I'm not sure what the correct IUPAC name is (It's a little bit beyond my ability to come up with myself), but I know that it is currently wrong...RustyShackleford731 (talk) 05:43, 24 October 2010 (UTC)

From the IUPAC nomenclature page: "The traditional names of simple monosaccharides, α-amino acids and a large number of natural products have been retained as preferred IUPAC names; in these cases the systematic names are very complicated and virtually never used." 96.54.32.44 (talk) 20:54, 6 February 2011 (UTC)

This is an archive of past discussions about Fructose. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Archive 1

Archive 2