Ask Dr. Marla: Lactose Intolerance or Milk Allergy?

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We switched our 10-and-a-half-month-old son to soy formula a couple of months ago with great results for his stomach cramps, spit-up and general happiness. Now we are wondering what to do as he approaches his first birthday and we are done with formula. We recently tried feeding him yogurt, which did not go well, and have attempted whole milk, too.


Milk and dairy products are often assumed to be the cause of gastrointestinal symptoms and inappropriate avoidance can lead to nutritional inadequacy, particularly for calcium intake. The question here is whether this is a dairy intolerance or allergy, or is this lactose intolerance? While you say that introducing yogurt did not go well, I am unsure if the symptoms you are talking about with real cultured yogurt and milk are the same. If the symptoms are exactly the same, then it is more likely there is a dairy intolerance rather than lactose intolerance.

What is lactose intolerance?

Lactose intolerance is fairly common and often can go undiagnosed. The inability to digest lactose occurs when lactose is not absorbed in the small intestine. It then passes through the gastrointestinal tract to the large bowel (the colon), where, in some people, it leads to symptoms of lactose intolerance. The typical symptoms include abdominal pain, bloating, gas, diarrhea, and on some occasions, nausea and vomiting. Fermentation of milk improves tolerance to lactose because of the presence of lactic acid bacteria. As a result, dairy foods in the form of cheese and fermented milk, such as yogurt, provide good sources of protein and calcium and often do not lead to symptoms of lactose intolerance.

The diagnosis

As your child seems to have symptoms with both milk and yogurt, it is more likely that this is a dairy intolerance. This does not mean that this is an allergy. A true allergy to casein, a protein found in milk, is much less common. There is no real magic to stopping formula at age one and switching to whole milk. Typically at one year, children are eating enough other food groups to not need the formula. If you are using soy milk, make sure that it is fortified with Vitamin D. Often the calcium is not as accessible and the calories are a little lower. It will be important to ensure that there is some fat in the diet.

Make sure your doctor is satisfied with your child’s growth and development for weight, height and head circumference. If you are still having difficulty with your child’s diet, discuss seeking a consultation with a paediatric dietician or paediatrician with expertise in nutrition.

Published in August 2010

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