What Populations Can Drink Milk? Understanding Lactase Persistence and Intolerance

January 2, 2026 •

5 min read

An estimated 65% of the world's adult population experiences some form of lactose malabsorption, meaning they lose the ability to fully digest milk after infancy. This widespread phenomenon helps explain why not all populations can drink milk without experiencing digestive discomfort.

Quick Summary

Global milk consumption is largely determined by the genetic trait of lactase persistence, which is not universal among adults. Prevalence varies widely by ethnicity and age, with most people in Asia, Africa, and South America unable to fully digest lactose. Special considerations apply to infants and vulnerable groups, necessitating dietary awareness and access to alternatives.

Key Points

Lactase Persistence is Not Universal: The majority of adults globally cannot digest lactose well, a genetic trait known as lactase non-persistence.
Genetic Factors Predominate: Prevalence of lactase persistence is highest in populations of Northern European and some African/Middle Eastern descent with long histories of dairying.
Milk is Not for Infants: Cow's milk is unsuitable as a main drink for babies under one year old due to nutrient deficiencies and potential kidney strain.
Not an Allergy: Lactose intolerance is a digestive issue, not an immune-system-related milk allergy, which can be life-threatening.
Alternatives are Plentiful: Individuals with intolerance can choose low-lactose dairy products (like hard cheese or yogurt with active cultures) or fortified plant-based milk alternatives.
Raw Milk is Dangerous: Vulnerable groups, including pregnant women, children, and the elderly, must avoid unpasteurized milk due to the risk of harmful bacterial contamination.
Tolerance Varies: The amount of lactose that can be tolerated varies widely between individuals, with many able to consume small amounts without symptoms.

The ability to digest lactose, the main sugar in milk, throughout adulthood is known as lactase persistence. This trait is not the norm for the global human population, and its distribution is a fascinating example of human evolution and adaptation linked to cultural practices like dairying. The global picture of who can drink milk is complex, involving genetics, age, and individual health factors.

The Genetics of Lactase Persistence

Lactase is the enzyme responsible for breaking down lactose in the small intestine. For most mammals and many humans, lactase production significantly decreases after infancy and weaning. However, a genetic mutation that allows the LCT gene (which controls lactase production) to remain active into adulthood, known as lactase persistence, evolved independently in various populations. The geographical distribution of this trait correlates strongly with historical pastoralist cultures.

Where is Lactase Persistence Most Common?

Northern European Descent: High frequencies, often exceeding 80%, are observed in populations from Northern and Central Europe, who have a long history of dairy farming.
African and Middle Eastern Pastoralists: Specific groups in Africa (e.g., Fulani and Tutsis) and the Middle East also developed lactase persistence, though with different genetic mutations than the one found in Europeans.
South Asian Populations: The trait is more common in Northern India compared to the south and east, aligning with regional cultural dietary patterns.

Where is Lactase Persistence Less Common?

East Asian Descent: Lactase non-persistence is highly prevalent, affecting 70–100% of East Asian populations.
Native American, Hispanic, and African American Descent: Significant portions of these populations have a reduced ability to digest lactose.

Special Population Considerations

Beyond genetics, specific age groups and health conditions impact who can safely consume milk.

Infants (Under 1 Year Old)

Cow's milk is not recommended as a primary drink for infants under 12 months.

Nutrient Imbalance: Cow's milk does not provide the correct balance of nutrients, such as iron, vitamin E, and essential fatty acids, that infants require for proper growth.
Kidney Strain: The high levels of protein and minerals can put a strain on a baby's immature kidneys.
Digestive Issues: It can cause intestinal irritation, potentially leading to micro-bleeding and iron deficiency anemia.

Pregnant Women and the Elderly

For vulnerable populations like pregnant women and the elderly, the safety of milk consumption depends heavily on proper processing.

Pasteurized Milk Only: Both groups, along with young children and the immunocompromised, are advised to avoid raw (unpasteurized) milk due to the risk of dangerous bacteria like E. coli, Salmonella, and Listeria.
Nutritional Needs: Milk can be a valuable source of calcium and vitamin D for the elderly to maintain bone density and prevent sarcopenia, the age-related loss of muscle mass.

Lactose Intolerance vs. Milk Allergy

It is critical to distinguish between lactose intolerance and a milk allergy, as they are two different conditions with vastly different implications.

Lactose Intolerance: A digestive issue caused by insufficient lactase, resulting in symptoms like bloating, gas, and diarrhea. It is not life-threatening, and many people can manage symptoms by limiting lactose intake or consuming processed dairy products.
Milk Allergy: An immune system response to milk proteins (casein or whey). Symptoms can range from hives and swelling to severe, potentially fatal anaphylaxis, and require complete avoidance of all milk products.

Managing Lactose Intolerance with Dietary Choices

For those who are lactose intolerant, various strategies allow for continued nutritional intake without discomfort.

Controlled Dairy Intake: Many individuals can tolerate small amounts of milk, especially when consumed with other foods.
Processed Dairy: Fermented dairy products like yogurt with live cultures and hard, aged cheeses (e.g., cheddar, Parmesan) contain less lactose and are often easier to digest.
Lactose-Free Products: These dairy products have the lactase enzyme added to break down the lactose, providing the same nutritional benefits as regular milk without the digestive issues.
Enzyme Supplements: Over-the-counter lactase enzyme tablets can be taken before consuming dairy products to aid digestion.
Plant-Based Alternatives: Soy, almond, oat, rice, and coconut milk are excellent, naturally lactose-free alternatives. However, it is important to check if they are fortified with calcium and other nutrients to match cow's milk nutritionally.

How Tolerant Are Different Populations?


Population Group	Ancestry	Lactase Persistence Rate	Historical Context	Typical Dairy Consumption	Associated Health Issues	Milk Alternatives Used
Northern European	European	Very High (~80-95%)	Long history of cattle domestication and dairying.	Regular, including fresh milk, cheese, and yogurt.	Low incidence of lactose intolerance issues.	Lower prevalence of plant-based milk use for this reason.
East Asian	Asian	Very Low (~0-30%)	Historically limited exposure to dairying in many regions.	Historically lower, though increasing in some areas.	High prevalence of lactose intolerance symptoms.	Soy, rice, and nut milks are common alternatives.
American Indian	Native American	Very Low (~0-20%)	No historical domestic dairying prior to European contact.	Typically very low or avoided due to intolerance.	High prevalence of lactose intolerance symptoms.	Culturally-specific foods and non-dairy options.
African American/West African	African	Low (~20-50%)	Patchy distribution, with some pastoralist groups having higher tolerance.	Varies widely by group and region; often low.	High prevalence of lactose intolerance symptoms.	Lactose-free dairy, fortified alternatives.
Hispanic/Latino	Hispanic	Low (~20-50%)	Varied ancestry, with prevalence influenced by indigenous vs. European lineage.	Varies, with many relying on lower-lactose dairy like cheeses.	High prevalence of lactose intolerance symptoms.	Lactose-free products, fortified alternatives.
Middle Eastern	Middle Eastern	Moderate to High	Long history of camel, goat, and sheep pastoralism.	Common consumption of fermented dairy like yogurt and cheese.	Varies, but many can tolerate processed dairy.	Fortified alternatives available.

Conclusion

Ultimately, the question of what populations can drink milk is answered not by a single rule but by a combination of genetic inheritance, age, and health status. While a significant portion of the global adult population is lactose intolerant due to a natural decrease in lactase production, many individuals can manage symptoms by controlling portion sizes or choosing lactose-reduced dairy products. For those with more severe intolerance or a milk allergy, a wide variety of lactose-free and plant-based alternatives are available to ensure adequate intake of essential nutrients like calcium and vitamin D. The decision to consume milk is a personal one, best guided by individual tolerance, dietary needs, and medical advice. It is always recommended to consult a healthcare provider for a proper diagnosis and personalized dietary guidance. For more information on dietary needs, consider exploring resources from the NIH National Institute of Diabetes and Digestive and Kidney Diseases.

Frequently Asked Questions

Yes, many lactose-intolerant individuals can tolerate small amounts of lactose. Products like aged hard cheeses (e.g., cheddar, parmesan) and yogurt with active cultures are typically well-tolerated because they contain very little lactose.

Lactose intolerance is a digestive problem caused by the body's inability to break down milk sugar (lactose). A milk allergy, however, is an immune system reaction to milk proteins and can cause more severe, potentially life-threatening symptoms.

Plant-based milk alternatives, such as soy, almond, and oat milks, have varying nutritional profiles. While many are fortified with calcium and vitamin D, their protein content can be significantly lower than cow's milk. It is important to check the nutritional label.

Cow's milk lacks the appropriate balance of nutrients, such as iron and vitamin E, for an infant's first year. Its high protein and mineral content can also be difficult for a baby's underdeveloped kidneys to process.

Lactase persistence is the genetic trait that allows some adults to continue producing the lactase enzyme, enabling them to digest lactose without experiencing digestive discomfort. This is the exception, not the rule, in the global adult population.

No, health authorities advise against consuming raw (unpasteurized) milk. It carries a significant risk of contamination with harmful bacteria and is especially dangerous for children, pregnant women, the elderly, and immunocompromised individuals.

Diagnosis can involve an elimination diet to see if symptoms improve, or a hydrogen breath test. The breath test measures the level of hydrogen in your breath after consuming a lactose-rich drink, with high levels indicating malabsorption.