The causes and symptoms of lactose intolerance
While serving on a mission in Botswana some years back, Dr Monir Islam – who is currently the World Health Organisation (WHO)’s representative in Namibia – noticed that he could not stomach fresh milk.
“I was working in Botswana and I used to take one flask full of boiled milk. I would drink it, but after some time I would start having diarrhea. That’s when I realised that I had a problem,” he said, explaining that the problem was caused by a condition called ‘lactose intolerance’.
Lactose intolerance refers to an inability to digest lactose, the main sugar in milk, which manifests in gastro-intestinal symptoms. It is caused by a deficiency of the intestinal enzyme, lactase, that splits lactose into two smaller sugars, glucose and galactose and allows lactose to be absorbed by the intestine.
In the case of Islam though, the lactose intolerance experience was mild and not severe. He noticed that the symptoms did not persist when he reduced his milk intake, nor did he have any problem when taking other dairy products, he says.
“If I drink a glass of milk I will not have the symptoms, but if I continually drink milk then I will have the symptoms. I really don’t drink fresh milk, or boiled milk for a long time, but if I have one cup there is no problem. If I have yogurt and other milk products I do not have a problem. It depends from person to person,” Islam explained.
He also explained that for some people lactose intolerance is congenital – where there is a lack of enzymes needed to digest lactose – because it runs in the family, while in some cases this enzyme is deficient.
This results in symptoms, such as diarrhea, bloating and too much gas each time a person who is lactose intolerant drinks milk. “It’s (lactose intolerance) not very dangerous for anybody, so if you’re not drinking milk you will not have any signs and symptoms,” said Islam.
Islam explained that limiting milk or drinking milk with other foods may work for some people with lactose intolerance, while some would need to get their calcium from other dairy products and in severe cases from calcium supplements.
The lactose enzyme may be deficient or absent and that’s why people have the signs and symptoms. He said it is not necessary to take a full glass, but small cup will do, to see how the body reacts.
“We don’t say when you have lactose intolerance you [should] completely avoid milk. You test to see how much of it will you tolerate, or you can also have other milk products.”
Dietician Samantha Du Toit explained that a very small section of the population is lactose intolerant. “Some people develop it after having severe diarrhea,” Du Toit said, adding that it’s not really a disease, but rather a condition that can be managed.