Which races can digest lactose? A look at human evolution and genetics

January 1, 2026 •

5 min read

About 65% of the world's adult population experiences a reduced ability to digest lactose after infancy. This variation, known as lactase persistence, is a genetic trait that allows certain races and ethnic groups to digest lactose throughout adulthood, while it is the exception rather than the norm for most of humanity.

Quick Summary

Adults in certain populations, primarily of Northern European descent and some African, Middle Eastern, and South Asian groups, retain the genetic ability to digest lactose, known as lactase persistence. This trait is less common in most other groups, including those of East Asian, Native American, and West African descent. The variation stems from different evolutionary histories related to dairy farming.

Key Points

Prevalence Varies Widely: The ability to digest lactose into adulthood (lactase persistence) is not universal and varies significantly across different races and ethnic groups.
Highest in Northern Europeans: Populations in Northern Europe have the highest rates of lactase persistence, with some areas having over 90% of adults retaining the ability.
Low in East Asians and Native Americans: Most East Asian and Native American populations have very low frequencies of lactase persistence, with most adults being lactose intolerant.
Co-evolution with Dairying: Lactase persistence evolved multiple times independently in populations with a long history of consuming milk from domesticated animals, such as cattle and camels.
Driven by Natural Selection: The survival advantage provided by milk as a food and hydration source in some environments drove the natural selection for this genetic trait.
Distinct Genetic Mutations: Different genetic mutations are responsible for lactase persistence in different parts of the world, highlighting convergent evolution.
Lactose Intolerance is Normal: Lactase non-persistence, leading to lactose intolerance, is actually the ancestral and most common condition for humans globally.
Factors Beyond Genetics: Individual tolerance can be affected by the gut microbiome, total lactose amount consumed, and whether it's eaten with other foods.

Understanding Lactase Persistence and Intolerance

Lactose is the main sugar found in milk, and its digestion requires the enzyme lactase, which is produced in the small intestine. In most mammals, including most humans, lactase production naturally decreases significantly after infancy, a phenomenon called lactase non-persistence. This is because milk is no longer a primary food source after weaning. However, certain human populations developed a genetic adaptation that allows them to continue producing lactase into adulthood. This trait, known as lactase persistence, is linked to a long history of consuming milk from domesticated animals.

Lactose intolerance is not a disease but rather the typical condition for most adults worldwide. When an individual with lactase non-persistence consumes lactose, the undigested sugar moves to the large intestine where it is fermented by bacteria, causing symptoms like bloating, gas, and diarrhea. The severity of these symptoms can vary greatly depending on the amount of lactose consumed and an individual's gut bacteria.

The Geography of Lactase Persistence

The ability to digest lactose as an adult varies significantly across different ethnic and racial groups. This variation is a clear example of gene-culture co-evolution, where a cultural practice (dairying) created a selective pressure that drove a genetic change (lactase persistence). The prevalence of lactase persistence is highest in populations with a long history of relying on unfermented dairy products.

Northern Europeans: Populations in Northern Europe, such as those from Scandinavia, Britain, and Germany, have the highest rates of lactase persistence in the world, with as many as 90% or more of adults being able to digest lactose. This is because early adoption of dairy farming created a strong evolutionary advantage for lactase-persistent individuals.
African Pastoralist Groups: While many people of African descent have high rates of lactose intolerance, certain pastoralist groups, like the Fulani in West Africa and the Beja in Sudan, have high frequencies of lactase persistence. This is attributed to a long history of herding and consuming milk from cattle, camels, and goats, leading to independent genetic mutations for the trait.
Middle Eastern and South Asian Populations: Moderate to high rates of lactase persistence are also found in some populations in the Middle East and Southern Asia, reflecting a history of dairying in these regions. However, the prevalence can vary significantly between different groups in these regions.

Populations with Low Lactase Persistence

Conversely, populations with little or no historical reliance on milk from domesticated animals have very low rates of lactase persistence. In these groups, lactase production naturally declines after infancy, and consuming significant amounts of fresh dairy can cause digestive issues.

East Asian Populations: People of East Asian descent, including those in China, Japan, and Korea, have some of the lowest rates of lactase persistence in the world, with as many as 90% or more of adults being lactose intolerant. Historically, their diets did not center on dairy products.
Native Americans and Indigenous Peoples: Native American populations also exhibit very low rates of lactase persistence, consistent with a history that did not involve dairy farming.
Southern European and West African Populations: Many people of Southern European descent (such as Greeks and Italians) and West African descent have low to intermediate frequencies of lactase persistence. This is often due to different historical patterns of dairy consumption or genetic lineage.

How Milk Consumption and Genetics Co-Evolved

The evolution of lactase persistence is a classic example of human gene-culture co-evolution. Around 10,000 years ago, as humans began domesticating animals, some populations started consuming milk products. For early dairy farmers, milk provided a reliable source of protein, fat, and hydration, particularly valuable during times of famine or in arid climates where clean water was scarce. The ability to digest this new food source offered a significant survival advantage, leading to natural selection favoring the genetic mutation for lactase persistence.

Importantly, this genetic adaptation occurred multiple times and independently in different parts of the world, resulting from distinct genetic mutations. For instance, the mutation most common in Europe is different from those found in some African populations, illustrating convergent evolution.

Genetic Variants and Alleles

The genetic basis for lactase persistence lies in mutations in or near the LCT gene, which provides instructions for making the lactase enzyme. The most well-known mutation, a C to T change at position -13910 (C-13910), is the primary cause of lactase persistence in Europeans. However, other distinct mutations in the same genomic region have been identified as drivers of the trait in African and Middle Eastern populations. This shows that the ability to digest lactose evolved independently in different geographical areas as a response to similar dietary pressures.

Comparison of Lactase Persistence Across Populations


Population Group	Prevalence of Lactase Persistence	Primary Genetic Variant(s)	Evolutionary Context
Northern European	Very High (80-96%)	T-13910	Early and widespread adoption of dairy farming conferred a strong selective advantage.
East African Pastoralists	High (e.g., up to 88% in some Beja groups)	C-14010, G-13915, etc.	Independent evolution driven by a history of consuming milk from livestock like cattle and camels.
West/Central African	Low, except for some groups like the Fulani	Variable, includes T-13910 in some pastoralists	Mostly low prevalence; exceptions linked to specific pastoralist traditions.
Middle Eastern	Variable (often moderate to high)	T-13910, G-13915	Ancient history of dairying, but with diverse genetic profiles and varying prevalence.
South Asian (e.g., North India)	Variable (Higher in the North)	T-13910	A history of dairying in the northern regions has led to moderate lactase persistence rates.
East Asian	Very Low (1-10%)	N/A (Ancestral state)	Lack of historical dairy farming meant no selective pressure to retain lactase production.
Native American	Very Low (<5%)	N/A (Ancestral state)	No dairy farming traditions prior to European contact.
Southern European	Lower than Northern Europe	T-13910 (less frequent)	Genetic drift may explain lower frequencies compared to their northern neighbors.

Lifestyle and Environmental Factors

While genetics provides the foundational explanation for which races can digest lactose, it is not the full story. An individual's lifestyle, gut health, and specific dairy consumption habits can also influence how they experience lactose intolerance. For example, even those with genetic lactase non-persistence can often tolerate small amounts of lactose, especially when consumed with other foods. The fermentation process in products like yogurt and aged cheese also reduces the lactose content, making them easier to digest for many.

Additionally, factors unrelated to genetics, such as intestinal injury, disease (e.g., celiac disease, Crohn's), or certain medical treatments, can cause secondary lactose intolerance. In these cases, treating the underlying condition may restore lactase levels over time.

Conclusion

The question of which races can digest lactose reveals a fascinating story of human adaptation and cultural development. Lactase persistence is not a universal human trait but a relatively recent genetic adaptation that co-evolved with dairying in different populations around the world. While high rates of lactose tolerance are found in Northern European and some African, Middle Eastern, and South Asian groups, low rates are typical for East Asians, Native Americans, and many West African populations. Understanding this genetic variation helps to demystify lactose intolerance, framing it not as a disorder but as a natural and normal human condition for the majority of the global population. For individuals, recognizing their genetic background and experimenting with dietary changes or lactase supplements can be key to managing symptoms effectively.

Frequently Asked Questions

No, being lactose intolerant is not abnormal. In fact, it is the natural and most common adult human condition globally, with about 65% of the world's adult population experiencing a reduced ability to digest lactose. The ability to digest lactose throughout adulthood, known as lactase persistence, is a relatively recent evolutionary adaptation.

The ability to digest lactose in adulthood is determined by a genetic trait called lactase persistence. Those with this trait, primarily found in populations with a long history of dairying, continue to produce the lactase enzyme. In most other populations, the lactase enzyme production declines after infancy, leading to lactose intolerance.

Populations of Northern European descent, particularly in Scandinavia, the British Isles, and parts of Germany, have the highest rates of lactase persistence, with some estimates suggesting 80-96% of adults can digest lactose.

No. While many West and Central African populations have low lactase persistence, certain pastoralist groups, such as the Fulani in West Africa and the Beja in Sudan, have high rates due to a history of consuming milk from domesticated animals.

Yes. The severity of symptoms depends on the amount of lactose consumed. Many with lactose intolerance can tolerate small amounts of dairy, especially when consumed with other foods or when consuming fermented products like yogurt and cheese, which have lower lactose levels.

Yes, genetic evidence shows that lactase persistence has evolved independently multiple times in different parts of the world, including Europe and several regions in Africa. This is a prime example of convergent evolution in humans.

The term 'race' is a social construct, and it's more accurate to link lactase persistence to specific ethnic groups and their ancestral reliance on dairy. The genetic variations influencing lactose digestion correlate with a population's historical diet, not race itself.