Talk:Lactose intolerance/Archive 2

Archive 1

Archive 2

suggestion for clarification

I did not have time to read this entire "Talk:" page, so feel free to enlighten me, "if applicable".

To me, the sentence

Congenital lactase deficiency prevents babies from drinking even human milk.

seems ambiguous. I read it as referring to "some" babies, or with the implied adverbial phrase "in some cases" missing but "understood".

Technically, however, that sentence could be interpreted as implying that all [or, almost all] [human] babies, are prevented (by congenital lactase deficiency) from drinking even human milk. IMHO, if that is not the intent, then the wording should be changed.

IMHO, either the word "some" ("some" babies), or else the adverbial phrase "in some cases" should be explicitly stated in that sentence. For example,

In some cases, congenital lactase deficiency prevents babies from drinking even human milk.

OR

In some cases, babies have congenital lactase deficiency which prevents them from drinking even human milk.

Ordinarily, I would have just been so bold as to go ahead and make that change, but the (huge!) portion of this "Talk:" page that I did read (but it's a small percentage of the whole "Talk:" page!), has caused me to think that I might be making a mistake, if I did not seek consensus first.

Any advice? or other comments? Thanks!... --Mike Schwartz (talk) 22:50, 14 January 2015 (UTC)

Actually, the "Terminology" section of the article, already contains (as its 3rd bullet point), this:

• Congenital lactase deficiency is a very rare, autosomal recessive genetic disorder that prevents lactase expression from birth.^{[footnote, "Heyman 2006"]} It is particularly common in Finland.^{[footnote, "Behrendt 2009"]} People with congenital lactase deficiency cannot digest lactose from birth, so cannot digest breast milk.

...so, *** maybe *** the revised sentence, should be something more like

In some (rare) cases, babies have congenital lactase deficiency, which prevents them from drinking even human milk.

(right?) --Mike Schwartz (talk) 23:27, 14 January 2015 (UTC)

Spelling differences

Just a trivial thing, but does anyone else think there should be a uniformity for the spelling of words within the article? Spelling "yogurt/yoghurt" both ways is cool and all, and technically correct, but I'm of the opinion that things like this distract from the article itself, and that's not cool. Thoughts anybody? RazingRazor (talk) 10:38, 19 April 2015 (UTC)

Agreed. And since "yoghurt" is a much more interesting spelling, why not let's use that one?Daqu (talk) 22:53, 9 May 2015 (UTC)

Mammilian Lactase persistence

The statement "Among mammals, lactase persistence is unique to humans –" at Lactase persistence needs strong support. Southern US farm families for generations had domesticated cats which were strongly attracted to dairy milk and routinely drank milk daily. I have never seen a cat get sick from drinking milk; perhaps they do - again it needs support since it runs counter to the experience of many rural people.
SBaker43 (talk) 01:16, 18 April 2012 (UTC)

I think this fact is well enough supported; it's stated in a number of the references, including the one actually cited in the section you're referring to ([1]).

As it happens, milk isn't good for cats or any other adult animal. It shouldn't be too hard to dig up your own sources for that. I suppose that's something that could fall under the scope of this article, actually. joe•roe^t•c 17:45, 8 May 2012 (UTC)

References or not, "human lactase persistence" is actually quite rare among ethnic groups. But the dairy industry would much rather you believed this myth.

It's true that there are many pictures and stories involving cats liking a bowl of dairy stuff. What is actually OK for most of them is cream — thick cream that is mostly butterfat containing relatively little lactose.Daqu (talk) 22:58, 9 May 2015 (UTC)

Norm

I think the article needs to make it clear that "lactase intolerance" is not really a "deficiency" but the norm among the peoples of the world. IN evolutionary terms Lactose intolerance is the ancestral terms and lactase persistence is the mutation that became prevalent as an adaptation in cultures that have a long history of dairy consumption. The point is that it is misleading to suggest that lactose intolerance is a medical problem or condition when in fact it is the ancestral condition which is still present in the majority of the worlds population.·ʍaunus·snunɐw· 15:47, 8 May 2012 (UTC)

As usual it's semantics. Absence of lactase is indeed the norm for adults and the ancestral condition for all mammals (I hope that's clear enough in the article – it's mentioned in the lead, again in the "Terminology" section and the section and article on lactase persistence goes into more detail on the evolutionary history) but nevertheless if you try to drink a glass of milk you'll find it a deficiency.

At the end of the day though it is thought of (and formally classified, and diagnosed, and treated...) as a medical problem in Western countries where milk-drinking is the norm and there's a plethora of reliable sources that take that position. We can't ignore those any more than we can ignore the global anthropological/evolutionary perspective. There are also variants of lactose intolerance that affect infants (i.e. acquired lactase deficiency and congenital lactase deficiency) which most definitely are medical problems, sometimes life-threatening ones, wherever you are in the world. joe•roe^t•c 17:56, 8 May 2012 (UTC)

I think there is good reason to distinguish more clearly between acquired and congential lactase deficiency that I agree are medical problems and the normal kind. This could be spelled out more explicitly in the lead I think. There is also literature in Darwinian medicine that criticize the medicalization of lactase inpersistence and the normalization of lactose tolerance (which for example has lead to nonsensical events such as the Chinese government trying to increase milk consumption in its highly lactose intolerant population using a copy of the "Got Milk" campaign).·ʍaunus·snunɐw· 18:01, 8 May 2012 (UTC)

It would be great to incorporate that literature into the article. Do you have any links? joe•roe^t•c 18:07, 8 May 2012 (UTC)

I'll look it up. I am thinking specifically of Wenda Trevathan's "Ancient bodies modern lives" which I have at home. I'll look at how to include it if you sdon't beat me to it.·ʍaunus·snunɐw· 18:09, 8 May 2012 (UTC)

• Here's an article we could use: "Cow's milk is accorded a high cultural value in the contemporary United States. Its white color, association with the maternal and the pastoral, and repeated mention in the Bible add positive symbolic weight to this major national agricultural commodity. Thus, it comes as no surprise that influential policy-making institutions in the United States recommend milk consumption for all U.S. groups. This is despite variation in adult populations' abilities to digest milk, which has been documented by biological anthropologists. This article assesses various U.S. “stories” about milk consumption and its relationship to biological variation against the biological anthropological explanation of variation in lactase activity/lactose tolerance. Many of these serve as normalizing discourses that ultimately pathologize biological difference and may undermine the dietary traditions of some ethnic groups. In particular, the close relationship between government and the dairy industry leads to policies that fail to seriously consider variation in digestive physiology among the diverse U.S. populations."(WILEY, A. S. (2004), “Drink Milk for Fitness”: The Cultural Politics of Human Biological Variation and Milk Consumption in the United States. American Anthropologist, 106: 506–517. doi: 10.1525/aa.2004.106.3.506)·ʍaunus·snunɐw· 15:54, 9 May 2012 (UTC)
• Another one by the same author that also argues about China and India: Andrea S. Wiley. 2011. Milk for “Growth”: Global and Local Meanings of Milk Consumption in China, India, and the United States. Food and Foodways. Vol. 19, Iss. 1-2, 2011·ʍaunus·snunɐw· 15:59, 9 May 2012 (UTC)
• This one is particularly critical: Wiley, Andrea S. (2007) Transforming milk in a global economy. American Anthropologist 109(4):666-677. "Large-scale milk production and consumption historically have been localized to Europe and countries with large Europeanderived populations. However, global patterns have now shifted, with dramatic increases in milk consumption in Asian countries and flat or declining consumption in European and European-derived countries. Efforts to market it around the world emphasize milk’s positive effects on child growth, and, by extension, the individual and national benefits that derive from that growth. At the same time, milk has newly emerged in milk promotions in the United States as food that facilitates weight loss. Milk has been able to achieve a global presence and continuing relevance in populations in which its consumption has been declining by continually transforming and repositioning itself as a “special” food with properties able to alleviate the health concerns seen as most salient at the time. "·ʍaunus·snunɐw· 16:07, 9 May 2012 (UTC)

I completely disagree that milk-drinking among adults is the norm in the U.S. Rather, the extremely influential dairy industry in the U.S. has for a very long time manipulated the federal government to list dairy as a "major food group" even though it is not at all that for most adults. Because the U.S. has had a lot of people of Northern European extraction, this myth has been allowed to stand.

One person above wrote: "If you try to drink a glass of milk you'll find it a deficiency." That is udder nonsense (pun intended) ! That is exactly as logical as saying that if you walk across the street without looking both ways you will find that your body's lack of armor plating is a deficiency. It is not just "semantics" at all, unless you actually look up the word "semantics" and find that its definition is the meanings of words. Yes! Meanings of words are important! They can express both truths and untruths.~

Before noticing this section I began a new one with the same point. But this cannot be said enough. And it looks to me as if the dairy industry has its own agents trying to manipulate this article.Daqu (talk) 23:14, 9 May 2015 (UTC)

Big problem with article

A big problem with this article is that it treats lactose intolerance as a disease or disorder — exactly what the dairy industry would like you to think.

It is not a disease. Quite the contrary, almost all ethic groups other than Northern Europeans lose much of their ability to digest milk by the time they are 5 to 8 years old.

I do not dispute that some diseases may be associated with lactose intolerance. And I do not dispute that lactose intolerance may be inconvenient and undesirable for people who have come to enjoy dairy products.

Referring to "lactase deficiency" — rather than to the normal process of lessened lactase production as a child grows older — is one way that this article keeps up the misleading appearance that lactose intolerance is a disorder.

This article needs to be rewritten in a big way so as to dispel the misimpression it gives that lactose intolerance is a disorder.

From a section above: "Lactose intolerance] is thought of ... as a medical problem in Western countries where milk-drinking is the norm and there's a plethora of reliable sources that take that position. We can't ignore those any more than we can ignore the global anthropological/evolutionary perspective."

More udder nonsense! Just because many people including supposed authorities on marriage statistics have written that the chance of a woman's ever marrying if she is still single by age 40 is the same as her chance of being killed by a terrorist. There is no basis for this claim. And just as it should be treated as the myth that it is, the very same thing applies the the often-repeated lie that lactose intolerance is a disorder. (For many decades and perhaps longer, a common medical myth believed even by many physicians was that if one burned one's fingers, a good remedy was to smear butter on the burn. It turns out there is no truth to this. So, in cases where the medical community has failed to grasp some truth, there is no reason in the world that the same myth should be believed or disseminated by anyone else.

We have a huge responsibility when writing for Wikipedia to adhere to what is actually true and not perpetuate falsehoods. At one point I noticed a falsehood was being perpetuated on Wikipedia and wondered why. The references that were used for this claim in this article, as well as hundreds more websites that repeated the myth . . . all traced back to that Wikipedia article in the first place. We live in a big echo chamber. There are many special interests who are constantly trying to hijack the vehicle of Wikipedia to promote "their own version of the truth", or more accurately their own lies. We must try our best to avoid letting them do this.Daqu (talk) 23:52, 9 May 2015 (UTC)

Agree completely. This article has some european systematic bias. It's not lactose intolerance which is strange, it's lactase persistence! Anyway, some rewording should be done. 50.187.216.93 (talk) 23:33, 4 August 2015 (UTC)

Adults or all people?

The lead says "inability of adults to digest lactose", but it also covers congenital LI. This is rather odd. I'm glad we have lactase persistence, but I think it's possible that this article should be replaced with "Congenital lactose intolerance" and "secondary lactose intolerance", and instead of primary lactose intolerance, "lactase persistence", cause that seems to be the most proper term. 50.187.216.93 (talk) 23:49, 4 August 2015 (UTC)

Ref error

I made a mistake referencing this paragraph:

"Healthy people with lactase nonpersistence are able to consume at least one cup of milk without developing symptoms and this tolerance is improved by consuming the milk with a meal (preferably lactose-reduced milk), adding lactase supplements, or replacing milk by yogurt or hard cheeses.

It was correctly removed by Doc James, because the reference is a primary source. edit: it is a review. Was there an error? But I mistakenly confused the source, the ref that supports this text is this other: PMID 20186234 NIH Consens State Sci Statements. 2010 Feb 24;27(2):1-27. NIH consensus development conference statement: Lactose intolerance and health. Suchy FJ, Brannon PM, Carpenter TO, Fernandez JR, Gilsanz V, Gould JB, Hall K, Hui SL, Lupton J, Mennella J, Miller NJ, Osganian SK, Sellmeyer DE, Wolf MA.

I will reword and restore it, with the appropriate refs, because is an essential information.

Best regards. --BallenaBlanca (talk) 22:42, 27 October 2016 (UTC)

References

K, Paraphrased a bit to shorten. Doc James (talk · contribs · email) 22:51, 27 October 2016 (UTC)

Thank you very much! Best regards. --BallenaBlanca (talk) 22:57, 27 October 2016 (UTC)

A2 beta-casein

I removed this text about A2 beta-casein to ask for opinion:

(Secondary lactose intolerance is due to injury to the small intestine such as from infection, celiac disease, inflammatory bowel disease,) and intolerance to A1 beta-casein (a protein present in the milk of most European-origin cows, but not in the milk of purebred African or Asian cattle, sheeps and goats).

Some of the authors of this paper have a COI: "Sonja Kukuljan is an employee of The a2 Milk Company (Australia) Pty Ltd. Keith Woodford previously consulted to A2 Corporation as an independent scientific adviser. The remaining authors declare no conflict of interest." Do we discard the reference in this context?

Best regards. --BallenaBlanca (talk) 01:09, 1 November 2016 (UTC)

References

Overly specific for the lead IMO. Other sources are not so convince and the COI of the authors raises concerns for me. Doc James (talk · contribs · email) 06:52, 1 November 2016 (UTC)

Thanks! I agree. Best regards. --BallenaBlanca (Talk) 12:12, 1 November 2016 (UTC)

"See Figure"

The Epidemiology section ends with "see Figure". Is it appropriate for Wikipedia? Should Figure be capitalized? Is it even a figure if it's a map? Should the location of the map be specified (i.e., the figure to the right)? What if due to the future edits the figure will be to the top or to the bottom? Shouldn't it be just removed?--Adûnâi (talk) 23:57, 25 March 2017 (UTC)

ICD

Why is it still classified as a health problem? If a minority were able to digest some poison, you wouldn't call out the majority for having a disease either because they have no tradition of consuming said poison. Furthermore, it's misused for white supremacist views. --188.99.180.226 (talk) 20:00, 1 April 2017 (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)

The map shows (1 - lactase-persistnce%) which is not the same thing as lactose intolerance. For example, only a small percentage of Sri Lankans (marked 60% - 80% in the map) have the lactase persistence allele, but only a very small percentage show any signs of lactose intolerance (probably because of gut bacteria). — Preceding unsigned comment added by 175.157.170.112 (talk) 13:44, 12 May 2017 (UTC)

Inaccurate Map: this map displayed in the article is 100% inaccurate and unscientific

Rates of lactose intolerance

The map displayed in the article is 100% inaccurate and unscientific. Numerous users have voiced their concerns and problems with this map yet it keeps being added onto the article with the excuse "there is nothing better". I believe showing no map is better than showing a map that actively misleads the public. There is no consensus and no reason to keep adding the map onto the article.

Why is it misleading?

1. It only uses two datapoints for South America. One of them is a study on Colombian Native populations while the other deals with Chilean Natives. Anybody that has a minimum understanding of South American demographics can realize the foolishness of extrapolating these two datapoints onto the neighbouring countries - In particular onto regions where populations of White European descent are the majority, namely Argentina, Uruguay and Southern Brazil. Thus to say the map deals with "current populations" is misleading, since that is not the case with the South American data.

2. A slew of countries in West and Central Africa are apparently mostly lactose tolerant despite the article stating that Sub-Saharan Africans are generally lactose intolerant. The only reasoning I could find in the article for this was that these countries all seem to be in the geographical distribution of the Fulani people, who, according to the article, are mostly lactose tolerant. But the Fulani are an ethnic minority in these countries, so their rate of lactose tolerance would not be indicative of the rate of lactose tolerance in the general population. One other issue is that in South Africa nearly 20% of the population has at least some European ancestry (whites and coloureds), the majority of which is northern European. And lactose tolerance being a "dominant" gene wouldn't that indicate that a person with full or partial northern European ancestry would most likely be lactose tolerant? This would put the figures of lactose intolerance lower than "91%-100%". In general I feel like if most of the African countries are just "rough guesses" than the information shouldn't really be there.

3. The map contradicts the sourced information in the article.

4. The sources listed for the map only deal with Thailand, Japan, Europe and North America. For the rest of the world it is based on extrapolation from latitude and specific native populations that may not be representative of the national situation.

5. The map contradicts known data for milk consumption per capita, which could be taken as a proxy for lactose intolerance, and a much more accurate one since it is sourced country-by-country information gathered by the FAO.

[Milk Consumption per Capita]

Finally one has to ask whether the purpose of this encyclopedia is to show articles that look good or to inform. If it is the latter, then this map should be removed, for it is better to have less information displayed than to have information that actively deceives and misleads the readers. Salem1313 (talk) 23:04, 2 July 2017 (UTC)

I agree to remove the map. The source is not reliable: [2] -> "Source. Own work Also here"

Best regards. --BallenaBlanca (Talk) 23:36, 2 July 2017 (UTC)

Source is given as

Densupsoontorn N, Jirapinyo P, Thamonsiri N, Chantaratin S, Wongarn R (2004): Lactose intolerance in Thai adults. J Med Assoc Thai. 2004 Dec;87(12):1501-5.

Scrimshaw NS, MurrayEB (1988): Prevalence of Lactose Maldigestion. Am J Clin Nutr 48 (Suppl): 1086-1098, 1988

Sahi T (1994) Genetics and epidemiology of adult-type hypolactasia. Scand J Gastroenterol 29 (Suppl 202): 7-20, 1994

Yoshida Y, Sasaki G, Goto S, Yanagiya S, Takashina K. (1975); Gastroenterol Jpn. 1975;10(1):29-34. "Studies on the etiology of milk intolerance in Japanese adults."

Doc James (talk · contribs · email) 04:03, 3 July 2017 (UTC)

This one here at least is a review[3]. Did you read it? Anyone have access and can send me a copy?

The map of milk consumption actually is fairly close to the one of lactose intolerance. Sure not as details but close. However partly milk consumption relates to wealth. Doc James (talk · contribs · email) 04:05, 3 July 2017 (UTC)

• Fits mostly with this map.[4][5] Except bit in the middle east and far Wast Africa needs to be adjusted.
• User:NmiPortal you able to update and take this into account?Doc James (talk · contribs · email) 04:27, 3 July 2017 (UTC)

Data

Chinese 100% Egypt, general 73% Vietnamese 100 Germany 70 Japanese 100 Hungary, general 56 Bantu, Uganda 100 Mexico, general 53 Peru, non-Caucasian 94 Northern Italy 52 Iraqi Jews 93 Fulani 50 Australian Aborigine 84 Greece 45 Nigeria Yorba 83 UK White 22 Ashkenazi Jews (LNP) 83 Finland (LM) 17 Moroccan Jews 82 US White, general 15 US Native American 81 Central Italy 15 Brazil 80 Irish 14 Chile 80 Danes 12 African American 75 Swedes 10

Fits fairly well with this. Doc James (talk · contribs · email) 04:37, 3 July 2017 (UTC)

Thank you for starting a talk page discussion, Salem1313. However please note that we usually try to reach a consensus before making controversial changes to an article (the bold revert discuss cycle). The map has been in the article for years so please leave it until we reach a consensus here.

I don't think anybody is going to argue that the map is accurate. It's based on a small number of data points, but it is broadly correct and well-sourced (certainly not "made up"). This map (Fig 1) is based on the most up-to-date data available and you can see it differs mostly in specific regions; the global trend is the same. I don't think milk consumption is a good proxy. Milk drinking is conditioned by a variety of cultural factors and often diverges from the frequency of the LP genotype/phenotype.

It would be nice to have a better map (if I have the time I can try and make one), but until we do this should stay. The global pattern of prevalence is a key fact about lactose intolerance and needs to be illustrated. It neither deceives or misleads: it's a faithful representation of the data sources used, which are reliable and cited for anyone who cares to look, and both the caption and the broad-stroke contouring identify it as a schematic view which is not going to be accurate for specific countries. If our readers click through to lactase persistence, they can find a table of detailed statistics. – Joe (talk) 07:31, 3 July 2017 (UTC)

I had not seen the references still now.

@Doc James:I got the article you requested. I sent it to you by email.

I have not been able to read it the references nor this complete discussion, I do not have now time. I'll do it later.

Best regards. --BallenaBlanca (Talk) 08:19, 3 July 2017 (UTC)

I appreciate taking time to address the concerns but I still do not understand your defense of this map. As you properly have listed, you've got nationwide information about lactose intolerance for only 17 nations out of 195 nations covered in the map. The other data points refer to ethnic minorities (like the Fulani) that are not representative of their respective countries. Why not color the remaining 178 nations with no data as "no data" rather than making asumptions that mislead the readers?

I do not think this map matches well with the milk per capita consumption map, in fact it greatly contradicts the information there - Greece is supposed to have 30-60% of its population as lactose intolerant, yet it is in the highest category of milk consumption. Costa Rica is listed as 60-80% lactose intolerant and Argentina as 80-100% lactose intolerant but their milk consumption per capita patterns are on par with Western Europe.

Common sense seems to suggest that extrapolating data based on geographic proximity, latitude, and ethnic minorites as has been done here will result in a misleading map.

Sadly I am afraid people will continue to bring up their issues with this map as can be seen in the history of this talkpage because the information contained there is contradictory with real life common sense and not based on real world data for the majority of the countries in question. Salem1313 (talk) 09:44, 3 July 2017 (UTC)

This map [6] seems considerably more accurate, reflecting variations in Africa which are consistent with the ethnic groups present there rather than latitude, and it shows the data points where information has been collected, with considerably more datapoints involved. Isn't there a way to add a version of this map to the article instead? It excludes the Western Hemisphere but it seems considerably more reliable based on the greater amount of datapoints used. Regards, Salem1313 (talk) 10:00, 3 July 2017 (UTC)

Percentage of adults that can digest lactose in the indigenous population of the Old World

Unfortunately we are limited to images that are available under a free license. But this discussion piqued my interest, so I spent this evening reproducing a similar map using their data that we can use. It only covers the Old World, but I think the added information is worth losing the Americas for. – Joe (talk) 21:29, 3 July 2017 (UTC)

References

That is absolutely amazing!! Excellent work, thank you for putting in the effort. Yes, this map has much more datapoints and seems much more accurate and trustworthy. I wholeheartedly support the new map and its inclusion in the article. For what is worth you have completely restored my faith in this encyclopedia. Excellent job. Regards, Salem1313 (talk) 18:27, 4 July 2017 (UTC)

• Why choose figure 1 rather than figure 2?
• That map does not mach some of the avaliable data I mentioned above either. Doc James (talk · contribs · email) 02:51, 5 July 2017 (UTC)
  • By the way milk consumption DOES NOT equal rates of lactose intolerance in adults.
  • LP allele frequency is also not a perfect representation of the phenotype. The maps are looking at the question in different ways. The FIN map is looking at surveys of symptoms the map by User:Joe Roe is looking at allele frequency and extrapolating from there.
  • Both are reasonable IMO. And both are extrapolating from a smaller number of points. Doc James (talk · contribs · email) 03:10, 5 July 2017 (UTC)

I don't mind having both in, but for the record the data I used is not an extrapolation from allele frequency. It's actual rates from diagnostic tests of lactose digestion (see "Determination of lactase persistence status" in Ingram et al. 2009). The only real advantage the FIN map has is that it includes the Americas. – Joe (talk) 07:44, 5 July 2017 (UTC)

Thanks User:Joe Roe see it now "Most data were obtained from lactose tolerance tests using either breath hydrogen or blood glucose, though in some cases enzyme assay data were available."Doc James (talk · contribs · email) 15:23, 5 July 2017 (UTC)

Have reached out to the creators of the map in question. They state that the refs listed are only some of the data supporting the map and that they will provide the rest as they have time. Doc James (talk · contribs · email) 02:57, 10 July 2017 (UTC)

Since it is supported by references, I agree to keep the map.

Best regards.--BallenaBlanca (Talk) 08:21, 10 July 2017 (UTC)

The original map used is accurate after all. It just needs more sources to verify the other part of the map. QuackGuru (talk) 14:41, 10 July 2017 (UTC)

Problem is both of that maps are nonsense, just level is different. The best example is Japan, both of maps are using silly stereotype that Japanese are lactose intolerant which maybe was true about 70 years ago. There was even reference about research in Japan showing that more than 80% of Japanese are lactose tolerant. "Indigenous population of the Old World" is some absolute nonsense showing whole Russia as lactose intolerant, research is just one huge nonsense, whole Russia is measured by one of indigenous small-numbered peoples sample. Rambalac (talk) 15:23, 10 July 2017 (UTC)

Sometimes accurate content is nonsense to some people.

The wording for each map:

"An estimate of the percentage of adults that can digest lactose in the indigenous population of the Old World[66]"

"Rough rates of lactose intolerance in different regions of the world"

Do you have any suggestions to improve the wording to make is more accurate (less nonsense)? QuackGuru (talk) 15:30, 10 July 2017 (UTC)

User:Rambalac are you suggesting that most people in Japan are not lactose intolerant when they become adults? If so please provide a reference to support that position. Doc James (talk · contribs · email) 15:44, 10 July 2017 (UTC)

Lactase_persistence, in the end.

When you publish reasearch about people of US dont use electronics after living in Amish village then yes, that is nonsense. Rambalac (talk) 15:55, 10 July 2017 (UTC)

Most people with lactose intolerance can "consume 200 ml of milk without severe symptoms" per "Most people with lactose intolerance can tolerate some amount of lactose in their diet and do not need to avoid milk or milk products completely."[7] Doc James (talk · contribs · email) 16:46, 10 July 2017 (UTC)

File:Lactose tolerance in the Old World.svg is not "nonsense", Rambalac. It is based on the best available data, using clear and consistent criteria from the scientific literature. The fact that it shows rates of lactose tolerance in indigenous populations is clearly stated in the caption. Recent migrant populations (e.g. ethnic Russians in Siberia) are excluded because they are not relevant to understanding the long-term evolution or phylogeography of lactose tolerance, which is what the map is intended to convey.

There is no reliable data from Japan – the study cited in lactase persistence is nearly 50 years old. Therefore its value on the map is extrapolated from the nearest available data points (Manchuria). That is a simple fact of geography and the only scientifically responsible thing to do. I do doubt that the Japanese have significantly different rates of lactose tolerance to other East Asians, though. And I have no idea why you think it would have changed in the last seventy years. – Joe (talk) 16:23, 10 July 2017 (UTC)

Management of intolerance caused by primary lactase deficiency

Since primary lactase deficiency is not a "disease", but a normal condition as in other mammals, we should not say that there is no "cure." The explanation of the NIH page is more accurate: "People with primary and congenital lactase deficiency cannot change their body’s ability to produce lactase."

In addition, it is possible to reduce lactose intolerance through regular consumption of foods containing lactose: "colon microbiome adaptation, which allow lactose intolerant individuals to overcome its intolerance." "However, regular dairy food consumption by lactase non persistent people could lead to colonic adaptation by the microbiome. This process may mimic a prebiotic effect and allows lactase non persistent people to consume more dairy foods enhancing a favorable microbiome."

I adjusted the page [8].

Best regards. --BallenaBlanca (Talk) 01:56, 13 August 2017 (UTC)

Agreed about "cure", it doesn't make sense in this context.

The info you added about adapting to lactose is appreciated but it duplicates the "Rehabituation to dairy products" section just below, so I have moved it accordingly. This seems to be a re-occurring problem with this article: people insert the same bits of information where it seems relevant to them, without checking if it's already in there, making the structure very confusing and repetitious. Please do skim the whole article (or at least the whole section) before editing it. – Joe (talk) 12:11, 13 August 2017 (UTC)

Thank you very much for your comments. However, it was not just a duplicate but a summary, since the sections normally contain a summary of the subsections. Anyway, it is better after your edit.

It is clear that this was not with bad intention, but please do skim copyright policies before saying that wording is a "copyvio" (and it was not even just a copy paste...). See NIH copyright policies [9] and, if you download the text in pdf format, you will be able to read "This publication is not copyrighted. The Clearinghouse encourages users of this publication to duplicate and distribute as many copies as desired." IMO, This explanation is more clear than this one.

Best regards. --BallenaBlanca (Talk) 14:24, 13 August 2017 (UTC)

Not seeing support

Were does the source say "progressive exposure to induce tolerance" as a treatment?[10] Doc James (talk · contribs · email) 20:39, 15 August 2017 (UTC)

My intention with this edit was to paraphrase, unify, and summarize the information not only of the source you are mentioning PMID 26893059 [11] but also from the NIH source already present (ref number one):

NIH. Lactose Intolerance. Eating, Diet, and Nutrition. People may find it helpful to talk with a health care provider or a registered dietitian about a dietary plan. A dietary plan can help people manage the symptoms of lactose intolerance and make sure they get enough nutrients. Parents, caretakers, childcare providers, and others who serve food to children with lactose intolerance should follow the dietary plan recommended by the child’s health care provider or registered dietitian. Milk and milk products. Gradually introducing small amounts of milk or milk products may help some people adapt to them with fewer symptoms.

PMID 26893059 Due to the beneficial prebiotic effects of lactose, it has been speculated that lactose nondigesting adults9,24 and premature infants with low and immature production of lactase16 should not avoid lactose but rather consume smaller amounts frequently to obtain the beneficial effects and avoid lactose intolerance symptoms. In adults, it has been shown that long-term ingestion of lactose can lead to diminished lactose intolerance as measured by the breath hydrogen test. This adaptation may be due to changes in the colonic microbiota or an upregulation of lactase.24

Maybe I should have put also this other two references:

PMID 26404364 4. How Do Humans Cope with Lactose Intolerance? ... Since most people with lactose intolerance can tolerate some amount of lactose in their diet they do not need to avoid milk or milk products completely. There are considerable variations in the amount of lactose that can be tolerated among lactose intolerant individuals. NIH experts suggest that adults and adolescents with lactose mal-absorption could eat or drink at least 12 g of lactose (the amount of lactose in 1 cup of milk) without symptoms or with only minor symptoms. Increasing lactose consumption may be possible if taken with meals or in small amounts throughout the day 51,52. Although no way to reinstate lactase production has been found as of 2015, some individuals have reported that their intolerance varies over time, depending on health status, pregnancy and adaptation to lactose intake 53, particularly through adaptation of the colon microbial system to lactose 54. ... A gradual introduction of small amounts of milk or milk products may help some people adapt to lactose with minor symptoms 55.

PMID 26287234 However, regular dairy food consumption by lactase non persistent people could lead to colonic adaptation by the microbiome. This process may mimic a prebiotic effect and allows lactase non persistent people to consume more dairy foods enhancing a favorable microbiome. This process then could lead to alterations in outcome of diseases in response to dairy foods in lactose maldigesters.

Another problem is to call it "treatment", but since it is a parameter of the infobox, we can not change it.

Best regards. --BallenaBlanca (Talk) 23:33, 15 August 2017 (UTC)

Maybe "Gradually introducing small amounts of milk or milk products may help some people adapt to them with fewer symptoms." would fit best in the body of the text.

It is already there. Doc James (talk · contribs · email) 04:35, 16 August 2017 (UTC)

Lactose Intolerance in Adults: Biological Mechanism and Dietary Management (Deng, Misselwitz, Dai and Fox, 2015 Sep)

By Yanyong Deng, Benjamin Misselwitz, Ning Dai and Mark Fox.

Published online 2015 Sep 18. doi: 10.3390/nu7095380

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4586575/

Abstract

Lactose intolerance related to primary or secondary lactase deficiency is characterized by abdominal pain and distension, borborygmi, flatus, and diarrhea induced by lactose in dairy products. The biological mechanism and lactose malabsorption is established and several investigations are available, including genetic, endoscopic and physiological tests. Lactose intolerance depends not only on the expression of lactase but also on the dose of lactose, intestinal flora, gastrointestinal motility, small intestinal bacterial overgrowth and sensitivity of the gastrointestinal tract to the generation of gas and other fermentation products of lactose digestion. Treatment of lactose intolerance can include lactose-reduced diet and enzyme replacement. This is effective if symptoms are only related to dairy products; however, lactose intolerance can be part of a wider intolerance to variably absorbed, fermentable oligo-, di-, monosaccharides and polyols (FODMAPs). This is present in at least half of patients with irritable bowel syndrome (IBS) and this group requires not only restriction of lactose intake but also a low FODMAP diet to improve gastrointestinal complaints. The long-term effects of a dairy-free, low FODMAPs diet on nutritional health and the fecal microbiome are not well defined. This review summarizes recent advances in our understanding of the genetic basis, biological mechanism, diagnosis and dietary management of lactose intolerance.

Keywords: lactose intolerance, lactase deficiency, lactose malabsorption, FODMAP, genetic test, hydrogen breath test, irritable bowel syndrome

Lactose and Lactase

Lactose is a disaccharide consisting of galactose bound to glucose and is of key importance in animal life as the main source of calories from milk of all mammals, all except the sea lion. Intestinal absorption of lactose requires hydrolysis to its component monosaccharides by the brush-border enzyme lactase. From week 8 of gestation, lactase activity can be detected at the mucosal surface in the human intestine. Activity increases until week 34 and lactase expression is at its peak by birth. The ability to digest lactose during the period of breast-feeding is essential to the health of the infant as demonstrated by congenital lactase deficiency that is fatal if not recognized very early after birth. However, following the first few months of life, lactase activity starts to decrease (lactase non-persistence). In most humans, this activity declines following weaning to undetectable levels as a consequence of the normal maturational down-regulation of lactase expression (Vesa, Marteau, Korpela, 2000). The exceptions to this rule are the descendants of populations that traditionally practice cattle domestication maintain the ability to digest milk and other dairy products into adulthood. The frequency of this “lactase persistence trait” is high in northern European populations (>90% in Scandinavia and Holland), decreases in frequency across southern Europe and the Middle East (~50% in Spain, Italy and pastoralist Arab populations) and is low in Asia and most of Africa (~1% in Chinese, ~5%–20% in West African agriculturalists); although it is common in pastoralist populations from Africa (~90% in Tutsi, ~50% in Fulani) (Swallow, 2003).

62.102.148.166 (talk) 15:50, 23 October 2017 (UTC)

What is the suggestion? Doc James (talk · contribs · email) 18:27, 23 October 2017 (UTC)

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Inaccurate map

I continually see two maps posted here

One with hotspots around Northern India, Arabia, various Africa, and North Europe.

Another with hotspots ONLY in north europe. The second map is inaccurate and contradicted within the article itself. — Preceding unsigned comment added by 69.116.121.138 (talk) 03:56, 8 May 2018 (UTC)

Which one do you feel is inaccurate? Doc James (talk · contribs · email) 22:48, 8 May 2018 (UTC)

You can always change the map if you think there are some mistakes in it, and provide sources.Dk1919 (talk) 08:31, 9 May 2018 (UTC)

Sardinia on the map

Hi guys, I left a post on the talk page related to the map on this page reading "Rough rates of lactose intolerance in different regions of the world", adding some more info about the island of Sardinia (that one island directly to the west of Italy). It'd be great if someone eventually changed the colour associated to the region. Cheers!Dk1919 (talk) 01:38, 21 April 2018 (UTC)

Yes updates to the map would be useful. Agree it could be more detailed. Doc James (talk · contribs · email) 03:06, 2 May 2018 (UTC)

Great! Unfortunately I don't really know how to edit the map, otherwise I'd already done it, but the colour associated to Sardinia would have to be changed to the bluest one (like Greenland, Iceland, etc.) in light of the new data, since most Sardinians (85% of the population) appear to be lactose intolerant (which is interesting, considering that it's such a stark difference compared to the European mainland and that the island has a long-standing pastoral tradition). Thanks for reading!Dk1919 (talk) 12:26, 2 May 2018 (UTC)

Download the map. Open it with an image editor tool. Adjust it and add the ref you used for the changes to the list. Doc James (talk · contribs · email) 03:34, 4 May 2018 (UTC)

Thanks for the suggestion. I managed to edit the map (I also added Corsica which was missing from the picture), but I don't know, once I get to the main page of the file, how to update it and "overwrite" the changes. Can you help me?Dk1919 (talk) 05:08, 4 May 2018 (UTC)

Go here https://commons.wikimedia.org/wiki/File:Worldwide_prevalence_of_lactose_intolerance_in_recent_populations.jpg

Clicked "Upload a new version of this file" Doc James (talk · contribs · email) 05:51, 4 May 2018 (UTC)

Thank you again, I've done it. Now, I hope I didn't screw something up... The picture with the changes was not always showing up on the file page.Dk1919 (talk) 10:44, 4 May 2018 (UTC)

I found where I think the problem is. The updated picture seems to show up until the resolution of 1,280 × 882, whereas the old version is displayed in the original resolution (1,722 × 1,187), which is strange since I didn't touch anything else apart from the colours.Dk1919 (talk) 11:09, 4 May 2018 (UTC)

Purging is required. Looks good to me :-) Doc James (talk · contribs · email) 07:20, 6 May 2018 (UTC)

@Dk1919 Franking:, I've reverted your edit on commons, although I'm sure it was made in good faith. I don't think it's a good idea to start modifying this map in bits and pieces. It is based on a single source that is cited in the description and, although you mentioned your source for Sardinia in your edit summary, that is not clear to readers. Even if it was, you're mixing two different datasets compiled with different methodologies and very different results. To but it bluntly, the data used to produce this map is garbage, so you've created a situation where it is accurate for Sardinia and inaccurate for everywhere else. Rather misleading :)

If you wanted to update the map I would create a new file and do the whole thing. On the other hand, we already have Itan et al.'s dataset, complete with the more accurate Sardinian data, in the article in the second map. – Joe (talk) 23:50, 29 May 2018 (UTC)

Is lactose intolerance a defect?

"Lactose intolerance is a condition in which people have symptoms due to the decreased ability to digest lactose, a sugar found in dairy products." Surely this is putting it the wrong way around. Lactose intolerance is not an illness or a defect or a "decreased ability." It is the normal state of being for humans as for all other lactating mammals. Lactose intolerance evolved in order to force young mammals to wean themselves off breast-milk as soon as possible. It is only since the domestication of cows and other milk-giving animals that the genetic predisposition for lactose tolerance has become established among humans, due to the evolutionary advantage it conferred on those who had it. That's why lactose intolerance is so much more prevalent in populations such as Indigenous Australians, since before the arrival of Europeans in Australia they had no milk-giving animals and hence no evolutionary incentive to develop lactose tolerance. I think the article should explain this and not treat lactose intolerance as a defect. Constant Pedant (talk) 23:17, 4 October 2019 (UTC)

wildtype

It seems to me that this article does describe the evolution of lactose tolerance, but just barely. Lactose intolerance is the wildtype. That is, the unmutated form that happened, as the article says, around 10,000 years ago. (The actual reason I am reading this is to find that number.) Most of the article seems to be described in terms of lactose intolerance, but the more unusual case is lactose tolerance. The article should better describe this. Though if Wikipedia is primarily for people of European origin, who mostly are lactose tolerant, it makes sense the way it is. Gah4 (talk) 07:49, 1 December 2020 (UTC)

@Gah4: This article is primarily about lactose intolerance as a medical condition. That's what it's considered in most of the western world, even if it's a misnomer in global terms. The evolution and global prevalence of lactose tolerance is covered in lactase persistence and to a lesser extent in #History. If I remember rightly, the idea behind splitting them was that there are two distinct perspectives on this topic: the medical one (where intolerance is the interesting phenomenon) and the anthropological one (where tolerance is the interesting phenomenon). It was difficult to integrate both into the same article, and readers looking for e.g. information about how the condition is diagnosed and managed would be just as disappointed as you were if they found an article about evolution and geography. So we treat them separately.

Personally I do agree that the medical perspective is over-emphasised in the current version – especially in the lead, where the anthropological perspective seems to have been whittled down to the bare minimum over the years and the link to lactase persistence is buried in the final sentence. But that is how the preponderance of sources talk about it, so for the most part we have to stick to that. – Joe (talk) 12:20, 1 December 2020 (UTC)

It does seem that it could be slightly better mentioned in the lede without getting so far from WP:DUE. As the article notes, pretty far down, most of the early and not so early research was done by people with lactose tolerance. That is, it is ethnocentric. There must be an ism for it, but I don't know which one. Gah4 (talk) 18:06, 2 December 2020 (UTC)

I've rewritten the last paragraph of the lead to try to give a more balanced perspective, mostly based on the existing material in #Epidemiology, #History and #Other mammals. I also came across a few interesting sources on the perception and cultural history of the condition that could be added to the body [12][13][14]. – Joe (talk) 12:39, 30 December 2020 (UTC)

Outdated info in history section

The history section of this article contains outdated and inaccurate inforation about the origin of lactase persistance.

Quoting relevant text from article:

"Around 8,000 years ago in modern-day Turkey, humans became reliant on newly domesticated animals such as cows, sheep, and goats. This newfound reliance resulted in higher frequency near the gene responsible for producing the lactase enzyme.[75] Populations that domesticated animals that could be milked continued to be lactase persistent in areas such as North and North western Europe, Scandinavia, the modern Middle East and Northwestern India. Populations that raised animals not used for milk made up the rest of the world's populations. These populations tend to have 90-100 percent of a lactose intolerant rate.[76] For this reason, lactase persistence is of some interest to the fields of anthropology, human genetics, and archaeology, which typically use the genetically derived persistence/non-persistence terminology.[77]"

The references [75] and [76] are from the years 2000 and 2012, respectively.

The statements here reflect the speculatory consensus that existed at the time, although these statements are written as if they were factual, when they were never actually tested with physical evidence.

However, in the last few years there's been an explosion in ancient DNA research that has shifted the focus on to a slightly different trajectory. It is no longer widely thought that lactase persistance originated among Anatolian farmers, as implied by reference [76]. It is now recognized that lactase persistance more likely originates from nomadic pastoralists living in the Steppe region north of Turkey, and that it spread from there about 4,000 years ago.

Quoting Michael Gross, [On the origin of cheese]

Before the advent of ancient DNA studies, a widely held but unproven assumption was that lactose tolerance was spread in Europe by the arrival of farming. However, in a study of 101 genomes of Bronze Age (3000–1000 BCE) Eurasians, the group of Eske Willerslev from the University of Copenhagen, Denmark, showed that, among the individuals sampled, only 10% of Europeans carried the trait (Nature (2015) 522, 167–172).

The highest prevalence of tolerance detected in that study was found among the Yamnaya of the Eurasian steppe, and the highest within Europe was among the Corded Ware cultures. At the same time, the group of David Reich at Harvard University, USA, has provided evidence of the Yamnaya expansion into Europe, and linked it to the Corded Ware cultures (Nature (2015) 522, 207–211). This expansion is now considered to be the most likely route for the arrival of Indo-European languages in Europe around 4,500 years ago

So the lactase persistance allele already existed in extraordinarily high percentages in the Yamnaya pastoralists at a time when farmers in Europe had less than half of what Yamnaya had. The spread of lactase persistance was a result of the spread of pastoralist ancestry from Eurasia, rather than natural selection in the farmers who migrated to Europe from Anatolia. Hunan201p (talk) 04:47, 16 May 2021 (UTC)