Consultancy Corner: What causes lactose intolerance in some people?

Until the fateful day we realised that some of us cannot digest milk. A few changes in our DNA do not permit us to utilise a critical component in milk – lactose, or milk sugar.

Cow’s milk, on an average, contains 87.7 per cent water, 4.9 per cent lactose, 3.4 per cent fat, 3.3 per cent protein and 0.7 per cent minerals. Milk composition varies with species, breed, feed of the animal and stage of lactation. The important component to consider here is lactose. All the carbohydrate in milk is in the form of lactose. 

To digest lactose, an enzyme called lactase (β-D-galactosidase) is needed. It is secreted within the intestines, after which it acts on lactose to break it down into the simple sugars, galactose and glucose. These are then absorbed. 

Since milk was consumed only by infants before the dawn of civilisation, during evolution, lactase production gradually decreased with maturity, since consumption of lactase decreased as the child matured. People who consumed milk even into adulthood maintained lactase production throughout their lives. Humans who settled in Europe, West and South Asia and parts of Africa have always consumed milk from cattle, sheep and goats as a major source of food. Individuals who descended from these ancestors show genes for lifelong lactase production. 

A startling fact suggests that around 70 per cent Indians are lactose intolerant. Although Aryans were heavy consumers of milk, since they originally inhabited Europe, the intermixing of genes with the original Dravidian population of the subcontinent led to the preponderance of genes that shut down lactose digestion with maturity. Symptoms of lactose intolerance are normally seen during teen or adult years, as the production of lactase decreases with age. Very rarely is a child born with lactose intolerance. In such cases, the newborn isn’t able to break down lactose in breastmilk or infant formula and suffers from severe diarrhoea. Such infants have to be given a lactose-free formula or else they will develop severe dehydration and weight loss. 

If you suffer from the above symptoms every time you consume milk or milk products, get a non-invasive, painless gene-based test done, to diagnose with absolute certainty that you have lactose intolerance. 

Technological advancements and our continuing understanding of the workings of the human body are helping us unearth information and insights into metabolism. We are now able to tap into the information inside our DNA. We can now read and understand the “blueprint of life” and use this powerful knowledge to create personalised strategies for lasting health and wellness.