Talk:Lactose intolerance

This Article Creates A Distorted View Of Lactose Intolerance -- What is the Truth?

I have noticed an abundance of statistics on the interenet related to lactose intolerance.

These statistics seem to fly in the face of experience.

1. How do you come up with 70-75% of the world population (4.5 billion people) being Lactose intolerant?

2. How accurate is this estimate? I have seen very little hard evidence except in major countries regarding Lactose Intolerance. This assumption seems to exclude Japanese from lactose tolerance, but Japanese stats show hugely increased milk consumption as do Australian dairy stats for exports to Japan. How is it the Japanese can NOW digest dairy products contrary to received scientific wisdom?

3. Indians are known to be lactose tolerant and we know of the sacred cows of India. Pakistan and Bangladesh are also of the same background. This is a huge part of the world population. Add North America and Europe. Add about half of South America.

4. China is now encouraging the consumption of milk and dairy products. So far, I have not heard of an epidemic of dead Chinese due to Lactose Intolerance.

5. Define Lactose Intolerance. The word intolerance is absolute. The implication is lactose intolerant people cannot eat and cannot digest dairy products. Obviously there are varying degrees of digestibility.

6. What are the true facts behind the statistics. What size are the samples? Where are the samples from? I have read at wrongdiagnosis.com that the stats on Lactose Intolerance are suspect and depend upon extrapolations of data from a very few western countries.

7. Many cultures which herded cattles and goats are able to digest lactose--this includes African and Mongolian herding cultures. —Preceding unsigned comment added by 142.106.169.166 (talk) 19:00, 2 July 2010 (UTC)

Re. Units... there is a comment that cheese might contain 10% of the lactose of milk. This is meaningless... is this per unit volume, per unit of dried milk solids, or something else? Meaningfull data would be helpful. —Preceding unsigned comment added by 24.150.112.2 (talk) 22:57, 15 July 2010 (UTC)

ok, not only those statistics are unreliable, but the map doesn't match those statistics. And another example of wront stat: for human group "Basques", only 85 individuals examined and the result is 0.3 %. That's mathematically impossible because 1 person out of 85 would make a minimum of 1.2 %. So it's either 30 % of intolerance or the number of individuals is greater, like 285. Coeur (talk) 11:40, 30 November 2010 (UTC)

Proposed split.

I've been trying to get to grips with this article in my head for a couple of hours now. I'm confused by it. Judging by the talk page, so are a lot of people. They come to the article looking for information on a medical condition, and they're confused by all the talk of percentages and what's "normal"; or they come here looking for information on an evolutionary trait, and they find only jumbled lists of statistics using inconsistent terminology. I think the core problem is that this article conflates several concepts: lactose intolerance, lactose malabsorption, lactase deficiency and lactase persistence. Not without reason of course; they're all facets of the same phenomena. But because those facets fall into different areas of academic study there are wide discrepancies in approach and terminology, discrepancies which this article makes a bit of a mess of dealing with. My proposal is that this article will only see significant improvement if it is able to commit to one approach, one set of terminology, and therefore it must be split into two:

• Lactose intolerance, the medical condition - with a brief summary of the prevalence of lactose intolerance around the world, but mainly focusing on the biological action, diagnosis, nutrition and treatment.
• A new article, lactase persistence, dealing with the ability to digest milk in adulthood as an evolutionary novelty in some human populations. So to start with it would consist of the current second and fourth sections (there's a lot more I'd like to add to this though).

I think the result would be two much cleaner, much more coherent, and much more understandable articles. —Joseph Roe^Tk•Cb, 19:49, 26 August 2010 (UTC)

• A good article about the problem of terminology: http://www.food-intolerance-network.com/index.php?option=com_content&view=article&id=33&Itemid=45 maybe it helps! NmiPortal (talk) 10:06, 18 January 2011 (UTC)

Lactose intolerance is not a disease or a malfunction, so it does not deserve to be called a 'medical condition'. No more than menopause is a 'medical condition'. Some women are menopaused very early, others very late, but menopause is natural. Creating some sort of separate article calling this a medical condition is unscientific and un-encyclopedic.--Tallard (talk) 16:23, 25 March 2011 (UTC)

Unscientific? Perhaps. But not unencyclopedic. We have to report the consensus amongst reliable sources, and it's quite clear that the medical community--and basically everyone who isn't specifically interested in LP as an evolved trait--considers lactose intolerance as a medical condition. —Joseph Roe^Tk•Cb, 17:38, 25 March 2011 (UTC)

Those numbers still represent the minority POV of humans who have lactase persistence. It fails at NPOV.--Tallard (talk) 21:24, 25 March 2011 (UTC)

If we were to consult, oh, Sleisenger & Fordtran's Gastrointestinal and Liver Disease, Chapter 101 or The National Digestive Diseases Information Clearinghouse, June 2009 publication 09-2751, they are medical publications talking about the medical condition Lactose Intolerance. The Mayo Clinic lists it as a medical condition. National Institutes of Health as well. I'd say that since it is verifiable through reliable sources, that Tallard is not showing any sources for an opinion. Your personal opinion about it doesn't make for encyclopedic information. --Catonsunday (talk) 03:02, 29 June 2011 (UTC)

Wow

Now, I'm not a stupid person, and I only come to wikipedia to learn things, however, this article is horrific. I have one main concern. The rehabilitation section says something about "Secondary Lactose intolerance". I have no idea what this is, however, the primary and secondary sections don't even explain the difference between this. It ends up being extremely vague, and confusing as to why either sections exist, because they certainly don't seem to add much, or explain much, this page isn't a fucking statistic report on lactose intolerance, simply put, put statistics with other statitistics, and information with other information, and merge the two as rarely as possible, now I have to google search to find if I might be able to rehabilitate myself :(. Sad face. Anyways, this page is shocking, people have edited and added information without maintaining a structure. For the benefit of everyone who might actually *need* good information (Students, people trying to self diagnose, or learn more about this), please address these issues. —Preceding unsigned comment added by 124.171.235.7 (talk • contribs)

this confusion was due to previous vandalism which had erased an entire section explaining this classification. It is fixed now.--Tallard (talk) 16:16, 25 March 2011 (UTC)

I'm going to do some research into it, because the Primary and Secondary sections don't seem to belong. There don't seem to be any sources for the information provided, but really, none of it matches up with what it should be talking about. The NDDIC has listed Primary and Secondary lactase deficiency, but it doesn't match the stuff that is in Primary and Secondary now. It seems that whole section needs to be redone, if not done away with. Catonsunday (talk) 03:50, 29 June 2011 (UTC)

Proposed split sounds great.

I like the proposal a lot.

@WOW: Primary and Secondary are most likely referring to Comorbidity of lactose intolerance in a patient. Primary would be a something like an enzyme deficiency, whereas secondary would be a side effect from another disease. The disease that pops up commonly in my searches as temporarily causing lactose intolerance is Celiac disease. Also, gastroenteritis (stomach flu) and food poisoning commonly causes secondary lactose intolerance.

A page discussing Celiac disease and lactose intolerance

I edited a number questionable statements in the foods content which had spurious references. I'm sure there's more work to be done, though. Dwlocks (talk) 06:49, 7 September 2010 (UTC)

Splitting these topics would be a very bad idea, there is nothing separate about them. Lactase persistence is but a recent (in evolutionary context) condition derived from favourable genetic mutations. --Tallard (talk) 16:19, 25 March 2011 (UTC)

I don't think that just because Lactase persistence is "recent" doesn't mean it isn't worth giving it's own page. Lactase deficiency should be separated from a lactase persistence/non-persistenceLactase persistence/non-persistence page would be a wise move, especially from a research standpoint. --Catonsunday (talk) 03:18, 29 June 2011 (UTC)

Correction in Lactose intolerance frequency map.

The lactose intolerance frequency for some of the countries is marked incorrectly on the map. The table depicts the data which does not go with the markings in the map. e.g. India is shown as 60 - 80 % intolerant as per the map, while the chart shows that that only 20 % of the population is lactose intolerant: on the other hand Italy, which is at an average (northern southern as well as sicily) 80 - 90 % intolerant is 40 - 60. I am sure if it is looked into properly, a lot more anomalies can be found. Request you to please correct it.

I would like to point out that almost the entire population in Argentina and Uruguay are of exclusively European ancestry, mainly Spaniards, Italians, and Germans. In the light of this, the map shown in the article is obviously wrong to anyone who has been there or knows something about the demographics of South America. If there is no data available for those countries, they should be grayed out since they are demographically very different from they neighbors. If not that, then at least the lines delimiting the individual countries should be removed from the map, to transmit the idea that it is referring to the native population that once lived in the region. —Preceding unsigned comment added by 77.179.215.113 (talk) 09:51, 22 November 2010 (UTC)

The map is not based on the same data as the table (see [1]). There very well could be errors, and even if not the lack of detailed sources for the statistics is problematic. But it seems to be the best freely-available map of LI available. Unfortunately preparing an alternative map is not as simple as looking up a figure for a country and colouring it in appropriately; there's lots of conflicting data that can't be really be put together. Some studies look at the modern population (useful from a medical POV) while others will only look at the indigenous people of a given area (useful from an evolutionary POV). Older studies may have methodological problems, particularly with regard to sampling, since before the 1970s the significant variation in LI between ethnicities was not widely known. Some populations have detailed stratified statistics available (e.g. the US), others only have broad regional surveys. In much of Africa, the Near East, and East Asia, doing things on a national basis would obscure considerable variation among ethnicities within a single country. Additionally, there's a range of ways you can define lactose intolerance, and although choosing one or the other could change the final figure by tens of percent, studies rarely say outright which one they are using. In other words, putting together a map that displays all the information in a way that is both accurate and consistent is a not a simple task. —Joseph Roe^Tk•Cb, 14:38, 29 November 2010 (UTC)

80-90% in italy? I'm confused, cause i'm italian and i'm the only lactose intolerant of my family (not only of my household, my entire family, grandparents, uncles, cousins)usually for breakfast italians drink cappuccino (coffe and milk), and eat fresh dairy products (mozzarella, burrata, stracchino etc.)

lactose intolerance is common,

but i do not think that affects the majority of italians. Rambaldo--Rambaldo (talk) 02:21, 29 January 2011 (UTC)

Well, as a general point, anecdotal evidence is no substitute for good statistics. It could be that you live in, or your family originally come from, an area of Italy that has a lower frequency of lactose intolerance than the national average (e.g. the north, uplands). Also, since lactose intolerance is primarily genetic, it's not surprising that the majority of the members of a family would have the same phenotype (non-lactose intolerance in this case). The typical Italian breakfast doesn't say much either: there's not enough milk in coffee to trigger symptoms in most lactose intolerant people, and cheese actually contains a very small amount of lactose because the lactose is turned into lactic acid in the fermentation process.

80–90% would be high. But if you look closely at the map south and central Italy is shaded in the 40–60% range while north Italy is only 20–40%. The table says 19% for central Italians, 41% for central Italians and 52% for northern Italians. Other studies cited in the article say 51% for northern Italians and anywhere from 4% to 72% of Sicilians. As you can see, there's a lot of variation within countries and that means the average may seem quite far off for a lot of people who are looking at a particular area. —Joseph Roe^Tk•Cb, 09:09, 29 January 2011 (UTC)

Merger proposal of redundant content fork

I propose that 'Lactase persistence vs. lactose intolerance and deficiencies' be merged into 'lactose intolerance', as the former article (an orphan article created 15 December 2010) appears to be a redundant content fork covering exactly the same topic as the latter article. Qwfp (talk) 21:11, 17 February 2011 (UTC)

Delete newer redundant article--Tallard (talk) 14:42, 25 March 2011 (UTC)

Redirect Lactose intolerance to Lactase tolerance. To treat lactose intolerance as a disease makes no more sense than saying black people are a disease! Lactase persistence is the scientific oddity and the article should reflect that.--Tallard (talk) 15:18, 25 March 2011 (UTC)

redirect Came here from NPP, seems a very clear case. HominidMachinae (talk) 07:32, 11 May 2011 (UTC)

The only problem with the merger I see is that the medical community is pushing to change the condition from "lactose intolerant" to "lactose non-persistence". Maybe change the title of the original "Lactose Intolerant" page to "Lactose Non-Persistence" to keep up with the medical terminology and then combine the pages? — Preceding unsigned comment added by Stephen Glansberg (talk • contribs) 02:38, 1 June 2011 (UTC)

Lactose intolerance, or lactace deficiency should be separated from the lactase persistence/non-persistence information. The 'Lactase persistence vs. lactose intolerance and deficiencies' would be better off as lactase persistence/non-persistence in it's own page. It would make sense for the two to link to each other, but to make it clear, they would be better off in separate pages. I do believe the original vs. page is not needed. Catonsunday (talk) 03:39, 29 June 2011 (UTC)

Southern South America

In southern Brazil, Argentina, Chile and Uruguai, the huge majority of the people (70-90%) have european origin (Portuguese, Spanish, Italia, German, Polish, etc.). These peoples arrived there mostly between 100-200 years ago, so they should be reasonably tolerant to lactose. How can the map show the people in this region as 80-100% lactose intolerant? Poor research IMHO. The map even show that area of south america as more lactose intolerant than northern south america, where european descendants are not as common. —Preceding unsigned comment added by 122.110.88.42 (talk) 09:23, 7 May 2011 (UTC)

It's probably based on indigenous populations. And no, the map is not perfect—nor is the table—but before you rush to call it "bad research" please read what I wrote above about the difficulty of getting compatible worldwide data. It's certainly impossible to capture both the modern frequency of lactose intolerance and the (evolutionarily relevant) precolonial situation on one map. But if you disagree, by all means fix it.   jroe ^tk_cb  10:24, 7 May 2011 (UTC)

This map has numerous problems:

1. Map doesn't cite data source
2. 80-100% lactose intolerance in the Chile/Argentina is wrong for the current population. If it's the indigenous population, then the US and Australia are inconsistent in showing the low LI in the current population.
3. Intra-country variation in Brazil, Bolivia, France, Italy, Spain and Russia. I strongly doubt there is any published data showing a difference in LI between Northern/Southern Brazil or Bolivia. Spain's difference maybe could be explained by the Basque, but the map color doesn't match the figures in the table for the Basque and non-Basque Spainards. Southern France is not colored appropriately based on the table. The map incorrectly (per the table) shows Southern Italians as more lactose intolerant than Northern Italians. Russia has a substantial number of non-Slavic people in the far East, but it's still 95%+ Slavic to a point much further east than the line on the map.
4. East African herders with low LI don't show up on the map
5. I have a hard time believing that Canada has higher LI than the US. While Canada has slightly more Asians and Native Americans, overall the US has far more people not of Northern European ancestry. Canada probably should be the same color as the rest of Northern Europe.

The map is quite misleading in a number of areas. The problem is in the Cono Sur is only the most obvious. I'm going to remove the map from the article.Plantdrew (talk) 19:17, 14 June 2011 (UTC)

Make it clear

Lactose intolerance here refer to lactase non-persistence, its completely different from the lactose intolerance in newborns and the lactose intolerance cause by bacteria infection, or even the milk allergic. Isuzu1001 (talk) 23:47, 19 June 2011 (UTC)

What are the symptoms?

Further information: /Archive 1 § What are the symptoms?

I also had trouble finding a mention of symptoms; at first glance it seems like there are no obvious symptoms apart from not getting as much nutrients. But looking closer it seems it is covered in the oddly-named “Overview” section (which the previous reader didn’t even pick up on). Surely overview is part of what the WP:lead section is meant to be. I think I’ll quickly merge the two. Vadmium (talk) 02:00, 21 June 2011 (UTC).