Regular milk has the highest levels of lactose, followed by fresh cheeses, commercially made yogurts and ice cream. Lactose is also an added ingredient in some baked goods, cereals, snacks, candies and salad dressings.
Lactose is a natural sugar found in milk and dairy products. It is also found in foods with labels that list the ingredients whey, curds, skim milk powder, dry milk solids and milk by-products. During digestion, the enzyme lactase breaks down lactose. A person whose body produces low levels of lactase cannot digest large amounts of lactose and may experience bloating, nausea, cramps, gas or diarrhea after consuming foods containing lactose. This condition is called lactose intolerance.
The more that milk products are fermented and aged, the less lactose they contain. This means that some people who cannot tolerate fresh milk or cheese can still enjoy moderate amounts of aged cheeses, yogurt or ice cream. Most grocery stores also carry lactose-free milk and cheese, and there is an over-the-counter enzyme replacement, Lactaid, that can be taken with food to improve lactose digestion.
Lactose intolerance is not medically dangerous, but people with severe intolerance need other sources of dietary calcium. Sources include broccoli, pinto beans, canned salmon or sardines with edible bones, canned tuna and salad greens. Soy milk and calcium-fortified orange juice are also good calcium sources.