How many people are lactose intolerant

What is lactose intolerance

Lactose intolerance is a recognized digestive condition, occurring when the body has a reduced ability to digest lactose, the main sugar in milk and dairy products. Often associated with discomfort and the need for dietary changes, the real scope of lactose intolerance—how many people it affects, severity levels, and demographic differences—remains an important topic in nutrition science and public health.

What percentage of people are lactose intolerant?

Globally, the prevalence of lactose intolerance varies significantly across populations due to genetic, geographic, and cultural factors. Estimates indicate that approximately 65–70% of the world’s adult population may experience some degree of lactose malabsorption, making it one of the most common digestive issues worldwide.

This high percentage is not distributed evenly. In certain regions, particularly East Asia, Sub-Saharan Africa, and South America, upwards of 80–90% of adults may be lactose intolerant. In contrast, populations in Northern Europe demonstrate lower rates, with an estimated 5–15% prevalence. These discrepancies are largely attributed to genetic differences affecting the persistence of lactase enzyme production into adulthood.

Are most people lactose intolerant?

Based on global figures, it is accurate to say that most adults worldwide may have some degree of lactose intolerance. However, this does not mean everyone is lactose intolerant or that symptoms are the same across populations. The persistence of lactase—the enzyme necessary for lactose digestion—is highly variable. While most mammals lose significant lactase activity after weaning, some human populations have developed lactase persistence through specific genetic adaptations, allowing continued milk consumption into adulthood.

Lactose intolerance in adults

Lactose intolerance tends to be more common in adults than in children, as lactase production often declines with age. This phenomenon, termed primary lactose intolerance, is a natural genetic process rather than a disease. In adults, symptoms can range from mild discomfort to digestive upset, depending on individual enzymatic capacity and lactose intake.

A smaller number of people may experience secondary lactose intolerance, which can result from gastrointestinal conditions or injuries that affect the small intestine, where lactase is produced.

Severe lactose intolerance and symptom variability

The severity of lactose intolerance varies widely. Some individuals can tolerate small amounts of dairy with little to no symptoms, while others may experience considerable discomfort after even minimal lactose exposure. Severe lactose intolerance often leads to symptoms such as bloating, abdominal cramps, diarrhea, and gas soon after consuming foods containing lactose.

To help manage such symptoms, dietary modification is typically recommended, such as limiting high-lactose foods or considering lactase supplements. For those looking for individualized solutions, specialized options are available. For instance, lactase enzyme supplements are designed to support lactose digestion.

Why are so many people lactose intolerant?

The high global prevalence of lactose intolerance is primarily linked to genetic evolution. Historically, most humans did not rely on dairy beyond infancy, so lactase persistence was not favored except in certain populations. The rise of pastoral societies, where dairy farming became common, led over generations to increased lactase persistence due to the nutritional benefits of milk. However, in many groups, the natural reduction of lactase after weaning remains the norm, explaining the contemporary distribution of lactose intolerance.