Lactose Intolerance
Jeanette M. Newton-Keith, MD

As a physician at the University of Chicago Hospitals, Jeanette Newton-Keith, MD treats patients with lactose intolerance. She is also an assistant professor in the medical school's Department of Medicine Biological Sciences Division and conducts research on lactose intolerance and the nutritional risk factors in the development of osteoporosis in obesity.

What is lactose intolerance?
Let's talk about how lactose is digested. A special enzyme in the small intestine breaks down the milk sugar, lactose, into carbon dioxide and water, which is absorbed by the body. We breathe out the extra carbon dioxide and the water goes into our cells. When there is more lactose than enzyme, it doesn't get completely broken down and absorbed in the small intestine. Instead, bacteria in the large intestine break it down and produce methane and hydrogen gas. This explains a lot of the symptoms people get - the gas, rumbling and flatus that we see with lactose intolerance.

Why do people develop it?
Most people don't have symptoms, even when the gut bacteria break down the milk sugar. But, there is a group of people who develop symptoms when they consume more lactose than the gut can process at any one time. But, we're finding that when you start with a small amount and gradually increase it, you have minimal symptoms. It is like a high fiber diet. By starting small and gradually building the amount in your diet, you will have minimal symptoms and still enjoy the health benefits of dairy foods.

How is lactose sensitivity different than lactose intolerance?
Lactose intolerance implies that you cannot consume any dairy. Lactose sensitivity helps to refocus thinking in a more positive way. It's like being fiber sensitive. If you eat too much fiber, what kinds of things will you experience? Usually, it's gas, bloating, diarrhea and flatus. Yet, we don't say we're fiber intolerant; we just adjust the amount to fit our diets. Milk is no different in terms of the health benefits it provides - the calcium, potassium, protein, and the other nutrients that are in dairy foods.

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