Europeans Are The Least Likely To Be Lactose Intolerant

[VikLevaPatel]

Lactase-persistence is the continued function of the lactase enzyme in adulthood. If you are lactase persistent, you are (usually) able to drink milk as an adult. Since it’s more common to be lactose intolerant in most populations, the genetic condition for being able to tolerate lactose into adulthood is referred to as lactase persistence.

This table shows that 12.3% of Africans have one or more alleles for lactase persistence, 57.1% of Finnish Europeans have alleles for lactase persistence, 0% of South Asians have alleles for lactase persistence, 0.06% of East Asians have alleles for lactase persistence, 10% of Ashkenazi Jews have alleles for lactase persistence, 60.1% of non-Finnish Europeans have alleles for lactase persistence and 20.3% of Latinos have alleles for lactase persistence. In other words, Asians are the most likely population to be lactose intolerant because of decreased activity of the lactase enzyme and non-Finnish Europeans are the least likely to be lactose intolerance from persistence of the lactase enzyme.

If you were to use this single genetic polymorphism as an estimate of lactose intolerance, you would assume that lactose intolerance is the least for non-Finnish European and the most for South and East Asian.

Interestingly, while Latinos are predicted to be more tolerant than Africans by genetics, 60-100% of the Latino population is predicted to be lactose intolerant.

Estimated lactose intolerance genetics by ethnicity from most intolerance to least intolerance (data from gnomAD):

South Asian
East Asian
Ashkenazi Jewish
African
Latino
European (Finnish)
European (non-Finish)

Did you know that 65% of the Human population has a reduced ability to digest lactose after infancy? Inversely, only about 5% of people in Northern European descent are lactose intolerant. But when you look at the Chinese population, over 90% are lactose intolerant. How can this be? It’s because of the LCT/MCM6 gene — LCT is one of my favorite genes! This gene is so interesting because it contains an important genetic polymorphism (rs4988235) that are highly variable in different populations. This genetic polymorphism causes lactase persistence.

https://archive.is/Utkaq#selection-271.0-291.106

Comparing Lactose Intolerance Genetic Polymorphisms to a Worldwide Prevalence Map of Lactose Intolerance:

https://archive.is/Utkaq/161e10be96b...3f4fe4e74.webp

Here's a table of lactose intolerance by country: https://archive.is/Utkaq#selection-547.0-547.49

[Ezio Auditore]

I am lactose intolerant. But I grew up eating and drinking lactose based products and I have no effects anymore.

[Perunovsin]

Im tolerant, and thank God, because I adore dairy products

[VikLevaPatel]

Sano Genetics

Genetic Report

Looking at several variants, we predict that you are...

MORE LIKELY TO BE LACTOSE INTOLERANT

At SNP rs145946881 you have the variant CC*, at SNP rs41380347 you have the variant TT, and at SNP rs4988235 you have the variant CC.

Based on your genotype, we predict that you are likely to be lactose intolerant. This report covers three genetic variants that are known to give rise to lactose tolerance. These variants are located at three different points (known as SNPs) on the MCM6 gene. You only need to carry one of the genetic variants to digest lactose.

*This genetic variant was not included in your original DNA data file. During our upgrade process, we determined your most likely genotype at this position using imputation.

Lactose is a type of sugar found in milk and milk products. An enzyme called lactase breaks down lactose into glucose - an important fuel for the body. When lactase is not present, lactose ferments in your small intestine and bowels, producing gasses which often cause bloating, diarrhea and stomach aches.

In most mammals the ability to produce lactase, (and so to digest lactose) is lost shortly after weaning. Most humans are also lactose intolerant:

68% of humans are thought to not be able to produce lactase after weaning

Geneticists have found variants which have popped up in different parts of the world (for example in Europe, Saudi Arabia, and Sub-Saharan Africa) that allow for the continued production of lactase.

What is lactose anyway?

Lactose is a type of sugar found in milk (and milk derivatives such as cheese) that is broken down by an enzyme called lactase [1]Jump to reference section: [1]. Lactase is an enzyme that breaks down lactose into glucose, which serves as an important fuel for our body. It is present in the small intestine, and this is where it does its work. However, when lactase is not present it leads to lactose fermenting in your small intestine and bowels, producing hydrogen, methane and carbon dioxide. These gasses often cause bloating, diarrhoea and stomach aches.

In the majority of mammals the ability to produce lactase, and therefore the ability to digest lactose, is lost shortly after weaning. Weaning is the process of introducing an infant mammal to its adult diet while withdrawing the supply of its mother's milk. This likely happens to allow the mother to transfer more of her energetic resources towards fertility again after her offspring has gained enough nourishment and is able to fend for itself.

The genetics of lactose intolerance

The loss of ability to produce lactase, scientists believe, happens because of a process called ‘methylation’ [2]Jump to reference section: [2]. Methylation is when, over time, chemicals in our body attach themselves to our DNA. In doing so, these chemicals stop our cells from being able to read the instructions from our DNA correctly, and can even cause the gene to ‘switch off’.

Many years ago, some medical groups referred to lactose intolerance as a ‘genetic fault’. But really lactose intolerance is the normal human state and 68% of humans are thought to not be able to produce lactase after weaning [3]Jump to reference section: [3]. Evolutionary geneticists uncovered that ancient humans (more than 10,000 years ago) would not have had the ability to digest lactose at all [4]Jump to reference section: [4]. But, for reasons we’ll explore, some humans have managed to keep their ability to produce lactase after weaning. This is known as ‘lactase persistence’.

The ability to produce lactase is thought to be mostly genetic, but the ability to digest lactose can be affected by external forces. For example, those whose lactase gene (LCT) ‘switches off’ after weaning can sometimes regain the ability later in life through picking up bacteria which help to break down lactose and decrease hydrogen production, therefore alleviating some symptoms [5]Jump to reference section: [5]. On the other hand, some people with the ability to produce lactase after weaning can lose it if their small intestine becomes damaged.

Geneticists have managed to pinpoint certain variants near the lactase gene which grant lactase persistence. But they also found that many single variants appear to have popped up all over the world and that each - on their own - allows for the continued production of lactase. For example, the majority of individuals from certain populations from Europe, Saudi Arabia, and Sub-Saharan Africa all have their own separate variant that allows them to produce lactase [6]Jump to reference section: [6],[7]Jump to reference section: [7],[8]Jump to reference section: [8].

Why are some people lactose intolerant and some not?

Evolving the ability to digest lactose by chance is very, very rare, so scientists started to investigate if other forces were at work that may have caused greater lactose tolerance in these populations. The answer is quite interesting! Evolutionary geneticists and anthropologists noticed that the same populations from Europe, Saudi Arabia, and Sub-Saharan Africa which were lactase persistent all had strong histories of milking [9]. However, other populations that had never adopted the practise of dairying their cattle had never evolved the trait.

Scientists now believe that the domestication of cattle and the process of milking them leads to the humans of that population evolving the ability to digest lactose. But this doesn’t mean that if you keep on drinking milk that you’ll eventually be able to digest it. What it does mean is that, in populations where dairying was practised thousand of years ago, being able to digest lactose meant you were far more likely to successfully pass on your genes [9]Jump to reference section: [9].

An evolutionary edge?

There are many theories as to why this might be, but a proposed explanation is that it leads to improved nutrition. For example, in a population that milked cows, being able to get calories from the breakdown of lactose into glucose and the absorption of important nutrients like calcium, likely means that people were able to live longer and have more children than those who were lactose intolerant [10]Jump to reference section: [10]. However, this effect likely isn’t as strong anymore, as many more sources of nourishment are now immediately available to many of us. Not to mention that you can now buy lactase to take as a pill if you’re lactose intolerant but still want to enjoy eating a pizza or having a milkshake!

References

[1]
Lactose and Lactase—Who Is Lactose Intolerant and Why?

[2]
Lactase nonpersistence is directed by DNA-variation-dependent epigenetic aging

[3]
Country, regional, and global estimates for lactose malabsorption in adults: a systematic review and meta-analysis

[4]
Microsatellite variation and evolution of human lactase persistence

[5]
Can changing the microbiome reverse lactose intolerance?

[6]
Identification of a variant associated with adult-type hypolactasia

[7]
The T/G−13915 variant upstream of the lactase gene (LCT) is the founder allele of lactase persistence in an urban Saudi population

[8]
World-wide distributions of lactase persistence alleles and the complex effects of recombination and selection

[9]
Evolution of lactase persistence: an example of human niche construction

[10]
Lactase persistence-related genetic variant: population substructure and health outcomes

Glossary

[SNP]
SNP stands for 'single nucleotide polymorphism' and refers to regions of DNA that vary between individuals.

[VikLevaPatel]

Sano Genetics

Genetic Report

Looking at several variants, we predict that you are...

MORE LIKELY TO BE LACTOSE INTOLERANT

At SNP rs145946881 you have the variant CC*, at SNP rs41380347 you have the variant TT, and at SNP rs4988235 you have the variant CC.

Based on your genotype, we predict that you are likely to be lactose intolerant. This report covers three genetic variants that are known to give rise to lactose tolerance. These variants are located at three different points (known as SNPs) on the MCM6 gene. You only need to carry one of the genetic variants to digest lactose.

*This genetic variant was not included in your original DNA data file. During our upgrade process, we determined your most likely genotype at this position using imputation.

Lactose is a type of sugar found in milk and milk products. An enzyme called lactase breaks down lactose into glucose - an important fuel for the body. When lactase is not present, lactose ferments in your small intestine and bowels, producing gasses which often cause bloating, diarrhea and stomach aches.

In most mammals the ability to produce lactase, (and so to digest lactose) is lost shortly after weaning. Most humans are also lactose intolerant:

68% of humans are thought to not be able to produce lactase after weaning

Geneticists have found variants which have popped up in different parts of the world (for example in Europe, Saudi Arabia, and Sub-Saharan Africa) that allow for the continued production of lactase.

What is lactose anyway?

Lactose is a type of sugar found in milk (and milk derivatives such as cheese) that is broken down by an enzyme called lactase [1]Jump to reference section: [1]. Lactase is an enzyme that breaks down lactose into glucose, which serves as an important fuel for our body. It is present in the small intestine, and this is where it does its work. However, when lactase is not present it leads to lactose fermenting in your small intestine and bowels, producing hydrogen, methane and carbon dioxide. These gasses often cause bloating, diarrhoea and stomach aches.

In the majority of mammals the ability to produce lactase, and therefore the ability to digest lactose, is lost shortly after weaning. Weaning is the process of introducing an infant mammal to its adult diet while withdrawing the supply of its mother's milk. This likely happens to allow the mother to transfer more of her energetic resources towards fertility again after her offspring has gained enough nourishment and is able to fend for itself.

The genetics of lactose intolerance

The loss of ability to produce lactase, scientists believe, happens because of a process called ‘methylation’ [2]Jump to reference section: [2]. Methylation is when, over time, chemicals in our body attach themselves to our DNA. In doing so, these chemicals stop our cells from being able to read the instructions from our DNA correctly, and can even cause the gene to ‘switch off’.

Many years ago, some medical groups referred to lactose intolerance as a ‘genetic fault’. But really lactose intolerance is the normal human state and 68% of humans are thought to not be able to produce lactase after weaning [3]Jump to reference section: [3]. Evolutionary geneticists uncovered that ancient humans (more than 10,000 years ago) would not have had the ability to digest lactose at all [4]Jump to reference section: [4]. But, for reasons we’ll explore, some humans have managed to keep their ability to produce lactase after weaning. This is known as ‘lactase persistence’.

The ability to produce lactase is thought to be mostly genetic, but the ability to digest lactose can be affected by external forces. For example, those whose lactase gene (LCT) ‘switches off’ after weaning can sometimes regain the ability later in life through picking up bacteria which help to break down lactose and decrease hydrogen production, therefore alleviating some symptoms [5]Jump to reference section: [5]. On the other hand, some people with the ability to produce lactase after weaning can lose it if their small intestine becomes damaged.

Geneticists have managed to pinpoint certain variants near the lactase gene which grant lactase persistence. But they also found that many single variants appear to have popped up all over the world and that each - on their own - allows for the continued production of lactase. For example, the majority of individuals from certain populations from Europe, Saudi Arabia, and Sub-Saharan Africa all have their own separate variant that allows them to produce lactase [6]Jump to reference section: [6],[7]Jump to reference section: [7],[8]Jump to reference section: [8].

Why are some people lactose intolerant and some not?

Evolving the ability to digest lactose by chance is very, very rare, so scientists started to investigate if other forces were at work that may have caused greater lactose tolerance in these populations. The answer is quite interesting! Evolutionary geneticists and anthropologists noticed that the same populations from Europe, Saudi Arabia, and Sub-Saharan Africa which were lactase persistent all had strong histories of milking [9]. However, other populations that had never adopted the practise of dairying their cattle had never evolved the trait.

Scientists now believe that the domestication of cattle and the process of milking them leads to the humans of that population evolving the ability to digest lactose. But this doesn’t mean that if you keep on drinking milk that you’ll eventually be able to digest it. What it does mean is that, in populations where dairying was practised thousand of years ago, being able to digest lactose meant you were far more likely to successfully pass on your genes [9]Jump to reference section: [9].

An evolutionary edge?

There are many theories as to why this might be, but a proposed explanation is that it leads to improved nutrition. For example, in a population that milked cows, being able to get calories from the breakdown of lactose into glucose and the absorption of important nutrients like calcium, likely means that people were able to live longer and have more children than those who were lactose intolerant [10]Jump to reference section: [10]. However, this effect likely isn’t as strong anymore, as many more sources of nourishment are now immediately available to many of us. Not to mention that you can now buy lactase to take as a pill if you’re lactose intolerant but still want to enjoy eating a pizza or having a milkshake!

References

[1]
Lactose and Lactase—Who Is Lactose Intolerant and Why?

[2]
Lactase nonpersistence is directed by DNA-variation-dependent epigenetic aging

[3]
Country, regional, and global estimates for lactose malabsorption in adults: a systematic review and meta-analysis

[4]
Microsatellite variation and evolution of human lactase persistence

[5]
Can changing the microbiome reverse lactose intolerance?

[6]
Identification of a variant associated with adult-type hypolactasia

[7]
The T/G−13915 variant upstream of the lactase gene (LCT) is the founder allele of lactase persistence in an urban Saudi population

[8]
World-wide distributions of lactase persistence alleles and the complex effects of recombination and selection

[9]
Evolution of lactase persistence: an example of human niche construction

[10]
Lactase persistence-related genetic variant: population substructure and health outcomes

Glossary

Glossary

[SNP]
SNP stands for 'single nucleotide polymorphism' and refers to regions of DNA that vary between individuals.

[Tongio]

Why would anybody want to steal milk from calves anyway.

[VikLevaPatel]

Why would anybody want to steal milk from calves anyway.

I would like to know just when the seemingly irrational cow worship came into practice in the lactose-intolerant Indian population.

Holy Cow!: An Indian Adventure
The Myth of the Holy Cow

W.W. Hunter, 2013, The Indian Empire: Its People, History and Products - Page 79:

Unlike the modern Hindus , the Aryans of the Veda ate beef ; used a fermented liquor or beer , made from the soma plant ; and offered the same strong meat and drink to their gods . Thus the stout Aryans spread eastwards Spread of ...

https://www.google.com/books/edition...sec=frontcover

the fact of widespread beefeating in the ancient India. 'The Vedic Aryans, including the Brahmanas, ate fish, meat and even beef. A distinguished guest was honoured with beef served at a meal. Although the Vedic Aryans ate beef, ...

https://archive.is/uBllw#selection-1505.0-1509.5

Colleen Taylor Sen, 2004, Food Culture in India:

Cattle played an important role in Vedic culture and cuisine , as they do in modern India . Called a " blessing , " the cow is ... The Aryans even ate beef — something anathema to many modern Hindus . ' 1 According to ancient texts ...

https://www.google.com/books/edition...sec=frontcover

John Murdoch, 1890, Religious Reform: Vedic Hinduism, Part 3:

When the Aryans entered the Punjab , they were largely a pastoral people , their flocks and herds affording a large proportion of their food . It has been shown that the Aryans in Vedic times ate beef and drank freely the intoxicating ...

https://www.google.com/books/edition...sec=frontcover

[VikLevaPatel]

High lactose tolerance in North Europeans: a result of migration, not in situ milk consumption

The main carbohydrate in milk is lactose, which must be hydrolyzed to glucose and galactose before the sugars can be digested. While 65% or more of the total human population are lactose intolerant, in some human populations lactase activity commonly persists into adulthood. Lactose tolerance is exceptionally widespread in Northern European countries such as Sweden and Finland, with tolerance levels of 74% and 82%, respectively. Theoretically, this may result either from a strong local selection pressure for lactose tolerance, or from immigration of lactose tolerant people to Northern Europe. We provide several lines of archaeological and historical evidence suggesting that the high lactose tolerance in North Europeans cannot be explained by selection from in situ milk consumption. First, fresh cow milk has not belonged to the traditional diet of Swedes or Finns until recent times. Second, not enough milk has been available for adult consumption. Cattle herding has been neither widespread nor productive enough in Northern Europe to have provided constant access to fresh milk. We suggest that the high prevalence of lactose tolerance in Finland in particular may be explained by immigration of people representing so-called Corded Ware Culture, an early culture representing agricultural development in Europe.

Perspect Biol Med. 2012;55(2):163-74. doi: 10.1353/pbm.2012.0016.

[Grace O'Malley]

Irish and Danish have the highest number of Lactose Tolerance.



https://eda.euromilk.org/fileadmin/u...ance_final.pdf

The ten countries with the lowest prevalence of lactose intolerance are:

Denmark - 4%
Ireland - 4%
Sweden - 7%
United Kingdom - 8%
New Zealand - 10%
Netherlands - 12%
Norway - 12%
Niger - 13%
Belgium - 15%
Cyprus - 16%

The ten countries with the highest prevalence of lactose intolerance are:

Ghana - 100%
Malawi - 100%
South Korea - 100%
Yemen - 100%
Solomon Islands - 99%
Armenia - 98%
Vietnam - 98%
Zambia - 98%
Azerbaijan - 96%
Oman - 96%

https://worldpopulationreview.com/co...nce-by-country

[Grace O'Malley]

Irish and Danish have the highest number of Lactose Tolerance.



https://eda.euromilk.org/fileadmin/u...ance_final.pdf

The ten countries with the lowest prevalence of lactose intolerance are:

Denmark - 4%
Ireland - 4%
Sweden - 7%
United Kingdom - 8%
New Zealand - 10%
Netherlands - 12%
Norway - 12%
Niger - 13%
Belgium - 15%
Cyprus - 16%

The ten countries with the highest prevalence of lactose intolerance are:

Ghana - 100%
Malawi - 100%
South Korea - 100%
Yemen - 100%
Solomon Islands - 99%
Armenia - 98%
Vietnam - 98%
Zambia - 98%
Azerbaijan - 96%
Oman - 96%

https://worldpopulationreview.com/co...nce-by-country

I don't know why there is a difference in numbers with Britain in the two results. I would have thought Britain would be similar to Ireland at any rate.

In Europe – and particularly in Ireland, Bradley's neck of the woods – lactose tolerance, or the ability to break down the sugar in non-human milk, is incredibly common. But it's not something that humans had in the early days of our evolution. A genetic variation allows humans to digest lactose.

"Ireland is the place in the world with the highest concentration of lactose tolerance," Bradley said, "and undoubtedly that’s to do with a heavy reliance on drinking unprocessed milk in pre-history, and a culture focused on dairying."

https://www.washingtonpost.com/news/...y-made-cheese/