Health Matters
What Is Lactose Intolerance?
By Kepha Nyanumba
Imagine enjoying a glass of milk, only to end up with bloating, nausea and abdominal cramps. For millions around the world, this is not just an occasional inconvenience, it’ s a daily reality. Lactose intolerance is the inability to digest lactose, a type of sugar found in milk and dairy products. Normally, the body produces an enzyme called lactase, which is responsible for breaking down lactose in the small intestine into two simpler sugars, glucose and galactose for absorption into the bloodstream.
In people with lactose intolerance, lactase production drops significantly, often after early childhood, leading to undigested lactose fermenting in the gut. This fermentation causes uncomfortable gastrointestinal symptoms such as bloating, gas, diarrhea, nausea, and abdominal cramps. These symptoms typically occur 30 minutes to 2 hours after consuming dairy, and their severity varies from person to person, depending on how much lactose they can tolerate.
There are several forms of lactose intolerance, classified based on the underlying cause. Primary Lactose Intolerance is the most common type. It is genetically determined and results from a natural decrease in lactase production after childhood. This type is particularly prevalent in Africans, Asians, and Native Americans. Secondary Lactose Intolerance occurs when the small intestine is damaged due to an illness or injury, such as gastroenteritis or celiac disease. The damage can temporarily reduce lactase production. Once the underlying condition is treated, lactose tolerance may improve.
The History of Lactose Intolerance
Lactose intolerance is not a modern condition. It is deeply rooted in human evolutionary history. Originally, all humans were lactose intolerant after weaning. This is because the natural decline of the lactase enzyme, which breaks down lactose( the sugar in milk),
Lactose intolerance is a digestive disorder that occurs when the body lacks enough lactase, the enzyme needed to break down lactose, the sugar found in milk and dairy products. As a result, undigested lactose ferments in the colon, leading to symptoms such as bloating, gas, abdominal cramps, and diarrhea. was a standard biological process. For most mammals, including early humans, lactase production decreased significantly after infancy, leading to an inability to digest milk in adulthood.
Scientific interest in lactose intolerance began growing in the mid-20th century, as global populations became more interconnected and Western diets often rich in dairy were introduced to non- Western communities. Many individuals from these regions experienced discomfort after consuming milk, prompting research into the condition. By the 1960s and 1970s, researchers had identified the biological mechanism behind lactose intolerance and developed diagnostic tests, such as the hydrogen breath test.
Globally, about 65-70 % of the adult population has some degree of lactose malabsorption. This high prevalence has shaped dietary habits and cultural food preferences, with traditional African diets relying less on dairy and more on alternative sources of calcium and protein. Lactose intolerance is now recognized not as a disorder, but as a natural variation in human digestion. Its history illustrates the intricate interplay between genetics, environment, and culture, showing how human evolution continues to respond to changes in diet and lifestyle.
The Difference Between Lactose Intolerance and Milk Allergy
Lactose intolerance and milk allergy are often confused, but they are distinct conditions involving different physiological responses to dairy. Lactose
110MAL66 / 25 ISSUE