ProViva Tummy School

Section 9: Lactose intolerance

Lactose intolerance is a condition in which the body has problems breaking down the lactose that we consume in our diet. Symptoms usually include diarrhea and stomach cramps. Normally the lactose molecule is broken down in the small intestine by the enzyme, lactase, which is present in most people. When the lactose is broken down glucose and galactose are formed, which can be absorbed by the intestine for use in the body. Lactase deficiency prevents this break down from occurring and the lactose molecule cannot be absorbed. Instead it continues undigested down into the colon, where it causes problems by nourishing intestinal bacteria and osmotically binding water. This results in loose stool and gas production – two completely harmless conditions that are nevertheless usually perceived as very troublesome.

All individuals, except for rare cases of congenital absence of the enzyme, are born with enough lactase to handle the lactose in breast milk. In most people production of the enzyme begins to decline starting at 2 to 5 years of age, and the majority of adults in the world therefore have impaired tolerance to dietary lactose. Most people in Northern Europe and North America, with a few notable exceptions, have retained the capacity to break down lactose, which enables them to drink milk even as adults. About 2 to 3 percent of the population in Sweden suffer from lactose intolerance, while among Africa's population about 90 percent are lactose intolerant.

A secondary form of lactase deficiency may arise in association with conditions such as chronic diarrhea, intestinal flu, or extensive injury to the mucous membrane of the small intestine as seen in celiac disease (gluten intolerance). These conditions may cause a period of lactose intolerance, but once the diarrhea or intestinal inflammation resolves the capacity to break down lactose returns.

What is the cause?

• Deficiency of the lactase enzyme, see above for causes

What can you do?

• Avoid foods containing large quantities of lactose such as dairy products
• Choose low-lactose alternatives. It is important not to discontinue all milk products since they contain many nutrients, especially calcium which is important for the skeleton
• Use trial and error to see what foods you tolerate. Usually no problems occur with consumption of less than about five grams of lactose (e.g., 1 dl milk, 2 dl cream, 5 dl low lactose milk) per meal, even if you suffer from lactose intolerance. Spread out foods that contain lactose throughout the day and do not consume large quantities on any single occasion.
• Products that contain lactobacilli (e.g., ProViva) can facilitate uptake of nutrients so that some of the lactose is absorbed by the body
• Eat hard cheeses in order to get enough calcium. All cheese that is aged for more than 2 months is essentially lactose-free and rarely causes any problems
• It is important that a doctor make the diagnosis so that you do not unnecessarily avoid important foods. The diagnosis is easy to make

• Do not confuse lactose intolerance with milk allergy. These are two entirely different conditions!