The fact that lactose intolerance symptoms are mostly developmental and seen as more prevalent in specific population groups, has led researchers to the clue, that this condition is genetically pre-disposed (read more: What is lactose intolerance?). It occurs far more frequently in Asian people; people of African heritage, and Native American populations; than it does for example in people of North European descent.
Lactose intolerance symptoms,
may occur due to damage caused to the small intestine, for example: surgery – subtotal gastrectomy, tropical sprue, ulcerative colitis, severe malnutrition, infectious hepatitis, kwashiorkor, and even certain types of antibiotic therapy. Symptoms typically include; bloating or distention of the stomach, gas (flatus), nausea, diarrhea and or cramps. Which also typically disappear once milk and milk products have been rigorously removed from the sufferers’ diet.
The reason for this problem is that the digestive enzyme lactase is missing – either partially or completely – from the wall of the small intestine. This then causes lactose intolerance symptoms which rarely appear in infants – unless in the case of a congenital defect, and which usually only appear after a child reaches 4 – 5 years of age; continuing into adult life.
When the enzyme lactase is missing from the digestive process, the primary sugar in milk – which is lactose – cannot be either digested or absorbed into the body. Lactose is a large sugar molecule, most prevalent in cows’ milk, which needs to be broken down into smaller parts to aid the digestion process. Lactose intolerance should also not be confused with being allergic to milk, and it is also important to remember, that not all lactase deficient people are lactose intolerant. There are varying degrees of ‘deficient’.
In adult-type hypolactasia (its scientific name), lactase deficiency affects almost the entire Asian population in the USA who are also lactose intolerant, 80% of Native Americans and 70% of people from African descent. In comparison, only 20% of the US Caucasian population is affected by lactose intolerance. As well as variability in population group, there is also wide variability in the prevalence ages of the affected.
Lactose intolerance symptoms
appear in Asian children at around five years of age. In children of Northern European descent – say for example the Finnish – this appears at approximately 20 years old, and in Black American as well as Mexican population groups, lactose intolerance symptoms may start showing around 10 years old.
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