Yogurt has long enjoyed a reputation as a healthful food, and rightly so. Yogurt is an excellent source of protein and calcium and is low in fat when made with fat-free or low-fat milk. In addition, if the starter cultures used to ferment milk into yogurt, Lactobacillus bulgaricus and Streptococcus thermophilus, are allowed to continue to live in the finished product, yogurt becomes a useful product to aid in digestion.
In recent years, several manufacturers have begun adding additional cultures to yogurt during processing in hopes of further fortifying the health-promoting potential of yogurt. Cultures most commonly added include Lactobacillus acidophilus, L. casei, L. reuteri and Bifidobacterium bifidum (Bifidus). These bacteria are considered to be "probiotics" because they are able to survive through the stomach to the gastro-intestinal tract. Once in the GI tract, they serve as friendly bacteria to help maintain a healthy balance between the 200-plus kinds of bacteria that live there.
A few manufacturers, including Stonyfield Farm and Yoso, also add the prebiotic inulin to several of their yogurt varieties. A prebiotic is a substance on which probiotics feed. Inulin, a soluble fiber, is thought to enhance calcium absorption, thereby enhancing the usefulness of yogurt to the body.
Just how healthful is yogurt? The most substantiated health claim about yogurt is its beneficial effect on digestion in some individuals. People who are lactose intolerant have a hard time digesting milk products because they lack the enzyme "lactase" that breaks down the main carbohydrate in milk. Yogurt is a unique dairy food because the starter cultures actually produce lactase during fermentation. Thus, the milk sugar in yogurt is more easily digested, even for lactose intolerant individuals. Many people who commonly experience gas, bloating or discomfort from dairy foods are able to digest yogurt more easily thanks to the starter cultures. This is especially true if the yogurt contains live cultures.
Claims regarding the usefulness of yogurts containing probiotics in reducing the risk of intestinal infections also have merit. Studies have shown, for example, that children suffering from chronic diarrhea recover faster when fed yogurt with probiotic cultures. Adults suffering from traveler’s diarrhea also seem to benefit. Scientists attribute this to the ability of probiotics to create an acidic environment that inhibits harmful bacteria.
Not all yogurts are worthy of praise, however. Heat set yogurts do not contain live cultures, and yogurt-covered pretzels, yogurt-covered candy and yogurt salad dressings are mostly just yogurt-flavored foods, not the real thing. Here are some tips for making wise choices at the yogurt display of your supermarket.
– Scan the label for "live and active cultures."
– Check out the calories. If a yogurt product has more than 250 calories per serving, it’s loaded with extra sugar or fat.
– Choose a yogurt with at least 20 percent of the Daily Value for calcium.
– Search the ingredient list for probiotic cultures like L. acidophilus and Bifidus and prebiotic ingredients like inulin.
– Pay attention to the expiration date. Culture counts decline over time.
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by Pat Kendall, Ph.D., R.D., Food Science and Human Nutrition Specialist, Colorado State University, Cooperative Extension