Lactose tolerance

Definition

Lactose tolerance refers to the ability of some adults to digest lactose, the sugar found in milk, due to the continued production of the enzyme lactase throughout their lives. This adaptation is significant as it demonstrates how certain human populations have evolved to utilize dairy products as a nutritional resource, particularly in environments where other food sources may have been scarce or unreliable.

5 Must Know Facts For Your Next Test

1. Lactose tolerance is most commonly found in populations with a long history of dairy farming, such as those in Northern Europe and certain African communities.
2. In contrast, many East Asian and Indigenous American populations exhibit high rates of lactose intolerance due to lower historical reliance on dairy products.
3. Genetic studies show that lactose tolerance is associated with specific mutations in the LCT gene that enable the continued expression of lactase into adulthood.
4. This trait exemplifies gene-culture co-evolution, where cultural practices such as dairy farming influence genetic adaptations in populations over generations.
5. Lactose tolerance can provide nutritional advantages, allowing individuals to access the calories and nutrients available in milk and dairy products, which can be crucial for survival in certain environments.

Review Questions

• How does lactose tolerance illustrate the concept of nutritional adaptations among different human populations?
  • Lactose tolerance highlights how some human populations have adapted nutritionally to their environments by continuing to produce lactase into adulthood. In cultures with a strong tradition of dairy consumption, such as those in Northern Europe, this genetic adaptation has allowed individuals to efficiently digest milk and its products. This illustrates the relationship between cultural practices, dietary needs, and genetic evolution over time.
• Discuss the implications of lactose intolerance on health and nutrition for populations with low lactase production.
  • Lactose intolerance can significantly impact health and nutrition for populations with low lactase production. Individuals may experience gastrointestinal discomfort and malnutrition due to their inability to digest lactose effectively, limiting their dietary choices. This can lead to lower calcium intake, which is vital for bone health, especially in societies where dairy is a primary calcium source. As a result, lactose intolerance necessitates alternative sources of nutrients or dietary adjustments.
• Evaluate the role of gene-culture co-evolution in shaping lactose tolerance among pastoralist societies and its broader impacts on human diets.
  • Gene-culture co-evolution has played a crucial role in shaping lactose tolerance among pastoralist societies. As these communities developed practices centered around dairy farming, individuals who could digest lactose gained nutritional advantages, leading to increased survival and reproductive success. Over time, this led to a higher prevalence of lactose tolerance in these populations. The broader impacts include changes in dietary patterns and agricultural practices, influencing food security and health outcomes across different regions globally.

Related terms

lactase: An enzyme produced in the small intestine that breaks down lactose into glucose and galactose, allowing for its absorption into the bloodstream.

lactose intolerance: A condition where individuals have low levels of lactase, leading to difficulties in digesting lactose and resulting in gastrointestinal symptoms after consuming dairy products.

cultural adaptation: The ways in which human cultures adapt to their environments, including dietary practices that arise from the availability of specific resources, like dairy in pastoralist societies.