Many people seem to believe that yogurt is a miracle food, the be-all and end-all of nutritional wonder-foods. Well, yogurt is good, certainly, but some of the claims are ridiculous. Test your knowledge on this true-or-false yogurt quiz:
1. Yogurt is more nutritious than milk.
True. Yogurt is basically milk and, in the United States, usually cow's milk. It has been fermented by adding bacteria that convert some of the milk sugar (lactose) into lactic acid. This gives it a tart taste and smooth consistency.
Yogurt is often even more nutritious than milk because it is usually thickened with nonfat milk solids, which provide added calcium. Typically, a cup of yogurt has 450 mg of calcium, compared with 300 in a cup of milk. This is 30% to 50% of most people's daily needs.
You can also get 20% to 25% of your daily protein needs from yogurt, which is a better source than milk of B vitamins (including folacin), phosphorus and potassium.
2. Yogurt is the best "diet" food for weight loss.
\o7 Maybe. \f7 A cup of yogurt can have from 90 to 350 calories, depending on what it is sweetened with and what kind of milk is used (whole, part skim or skim). The milk used also affects the grams of fat, which can range from 0 to 11. Plain yogurt may have no sugar, but varieties such as vanilla, coffee and lemon contain as much as 31/2 teaspoons of sugar. The fruit flavors may have as much as seven teaspoons.
It is important to carefully read yogurt labels before buying. Look at container size. These figures are for 8 ounces; some yogurts come in 6-ounce cups.
3. Yogurt is easier to digest than milk.
\o7 True\f7 . Many adults who have trouble digesting lactose can eat yogurt because the bacteria break down some of the lactose in milk. In some cases, the bacteria may stay alive for a while in the intestinal tract; in this case, they will continue to help digest the lactose. Each person's reaction will vary depending on the yogurt brand and the degree of lactose intolerance.
4. Frozen yogurt is as nutritious as regular yogurt.
\o7 False. \f7 It seems there are no federal standards regulating frozen yogurt. Most frozen yogurts are only slightly fermented, so they may not work for people who are lactose intolerant. They have far less calcium than regular yogurt, and some are high in calories and fat. The frozen yogurt itself may be low-or non-fat, but the added stuff may sabotage this treat.
5. Yogurt can boost the immune system and cure many bacterial infections.
\o7 Maybe, but probably not. \f7 A study by scientists at UC Davis several years ago found that people who ate two cups of yogurt with live cultures every day for four months had a higher level of a specific chemical that plays an important role in immune function.
Nobody knows what the practical effect on immunity might be. Experiments to test yogurt as an infection fighter have been inconclusive and largely based on poorly controlled studies or on products not available in this country.
6. Yogurt will prolong your life.
\o7 False. \f7 Early in the 20th century, there were reports that 100-year-old Bulgarian peasants ate large quantities of yogurt. Thus, people speculated that the yogurt's bacteria protected the Bulgarians against disease. Actually, the peasants didn't really know how old they were, and even if they were only in their 80s, it's far more likely that their longevity was due to their vigorous outdoor lifestyles.
Dr. Sheldon Margen is a professor of public health at UC Berkeley; Dale A. Ogar is managing editor of the UC Berkeley Wellness Letter. E-mail email@example.com. Eating Smart appears occasionally in Health.