Milk and dairy products are an excellent source of the calcium that everyone needs to build and maintain strong bones. But, many people with Crohn’s disease avoid dairy for fear that it will cause symptoms such as excess gas, bloating, cramping, and diarrhea. While it’s true that some individuals are lactose intolerant, dairy isn’t necessarily something that Crohn’s patients need to avoid.

Lactose is a carbohydrate, a sugar found exclusively in milk and milk products. Humans are born with the ability to break down lactose into its smaller, more digestible components. This initial step in digestion is achieved with the help of an enzyme, a protein called lactase, which is tailored to break the lactose molecule down into its smaller constituents, which are then absorbed by the intestines.

Some adults lose the ability to produce lactase. Lactase deficiency is less common among people of Northern European decent and more common among people of Mediterranean and African descent. 

When lactose intolerant people consume milk, they may experience some unpleasant intestinal discomfort, due to the intestines’ inability to process the sugars in milk. For some of these lactose intolerant people, milk in small quantities (about a half-cup at a time) is not a big problem. People who are truly lactose intolerant can take supplemental lactase in a capsule to help them digest milk properly. 

Even if the Crohn’s patient is truly lactose intolerant (and not every patient is), it’s possible to safely consume certain dairy products that contain very little lactose. Low-lactose products include aged, hard cheeses—such as savory parmesan or aged cheddar—and yogurt.

Lactose is soluble in water, so any food that’s made through a process that eliminates water usually contains less lactose. Clarified butter, for example, can safely be tolerated by most lactose intolerant people, because it has virtually no remaining lactose. Aged cheeses (aged two years or more) are also safe bets, due to exceptionally low lactose content.

The Elimination Diet

Although dairy is often one of the first foods Crohn’s sufferers eliminate from their diets, not every patient is actually lactose intolerant, so avoiding all dairy may not be necessary. It could even be counterproductive, since dairy is an excellent source of calcium, which is particularly important for Crohn’s patients, as drug therapy, malabsorption, and other factors often cause a deficiency in this essential nutrient.

Rather than avoid dairy unnecessarily, it makes more sense to try an elimination diet. An elimination diet is an approach that may help identify food allergies or food intolerances. The patient removes a single food, or type of food, from their diet for anywhere from two weeks to two months. Patients or their caregivers keep a food journal, noting what, when, and how much, the patient eats and what, if any, symptoms of intestinal distress follow.

By tracking the patient’s progress before making any further changes to the diet, it should be easy to identify which foods trigger symptoms. If symptoms disappear, it can be assumed that the patient has an intolerance for the food that was eliminated. This can be confirmed by carefully adding the food back into the diet. If symptoms reappear, it can be assumed that the food isn’t well tolerated. Conversely, if symptoms persist during the elimination phase, it can be assumed that the food isn’t part of the problem, and the food can be reintroduced into the diet.

Is There a Link Between Dairy Farming and Crohn’s Disease?

Crohn’s disease is presently believed to be an autoimmune disease with an unknown cause. Experts agree that food doesn’t play a role in triggering the inflammation that damages the intestinal tract, but in recent years, some scientists have proposed a possible link between the dairy industry and Crohn’s.

The scenario goes like this: Many cows are infected with a microbe with the tongue-twisting name, mycobacterium avium subspecies paratuberculosis (MAP). In cows, this germ is linked to an illness very similar to Crohn’s disease. Some scientists are now speculating about and investigating a possible link between this germ and human Crohn’s disease. While it may not cause Crohn’s disease outright, they argue, it may act as a trigger among humans for the damaging inflammation and destruction of the gut lining that is the hallmark of Crohn’s. The germ is sometimes present in pasteurized milk, beef, and even drinking water in some locations.

A recent study in Italy identified this germ in the intestinal tissue of more than 82 percent of Crohn’s patients, suggesting a possible role for the organism. But healthy controls also showed signs of exposure to the germ, albeit at lower rates. Therefore, association between MAP and Crohn’s remains controversial. Other studies have implicated other germs that may play a role in the disease, but nothing is presently certain. In any event, the possible links among dairy farming, MAP and Crohn’s disease in humans deserve far greater scrutiny. If eventually proven, it might lead to better treatments, as appropriate antibiotics might eliminate the underlying MAP infection.