Many centuries ago, the Mongols of Asia were reported to eat a strange food that had medicinal properties, and it was said that they enhanced its flavor by mixing the sour-tasting food with the blood of horses. When the secret recipe of this food; which was believed to extend human life, was brought from Constantinople to France, King Francis I bought the formula for a large sum. In 1931 a Spanish businessman, Isaac Carasso, produced the food and sold it in pharmacies throughout Europe. With the advent of World War II, Carasso;s son, Daniel, bought the formula to the United States. The food, then named Danone, after Daniel, was slow to catch on because people thought that the sourness meant it had spoiled. Fruit was added to balance the sourness and sales of the product, renamed Dannon yogurt, improved. In the 1970's, yogurt became known as a high-protein, low-fat health diet food. Some people concluded that it must be good for you if health-conscious people were willing to eat something so sour. In 1985, television advertisements for Dannon yogurt showed happy Asians eating lots of yogurt. They looked healthy and very old. The ads reinforced the notion that yogurt promotes longevity. LONG LIFE Scientific-sounding claims that yogurt is good for you can be traced to the turn-of-the-century theories of Elie Metchnikoff, a respected Russian biologist who won a Nobel prize for medicine in 1908. Metchnikoff believed that our life span is limited by bacteria. In his book, "The Prolongation of Life", he stated the intestinal tract harbored great numbers of bacteria that produced toxins that slowly poisoned the body and caused premature death. He called this process, "autointoxication by putrefactive bacteria," and believed that surgical removal of the colon where the bacteria lived would extend life. However, because colon surgery carried considerable risk, he recommended another treatment that he believed would rid the human intestine of harmful bacteria. Metchnikoff had studied the culinary practices of French, Russian, and Bulgarian peasants and noted that the Bulgarians, who consumed about three quarts of yogurt a day, had remarkable longevity. He concluded that the lactobacilli bacteria, Long Life Which are present in yogurt, establish colonies in the intestines and displace the harmful bacteria. Although it was unproven, Metchnikoff wrote books that popularized his theory. He also ate lots of yogurt, and announced that he expected to live to the age of 150. Later, tests showed the Lactobacillus bulgaricus bacteria do not colonize in the human intestine, leaving Metchnikoff with no scientific basis for his beliefs. When we are born, our intestines are relatively sterile and free of bacteria. As daily food is consumed, the intestines quickly adopt colonies of bacteria. Adult intestines contain a vast range of flora, lactobacilli, streptococci, staphylococci, coli form bacteria, and yeast. In this competitive environment, the yogurt bacteria are unable to establish colonies. To be fair to Metchnikoff, the idea that intestinal bacteria can be harmful may have some merit. Today, medical experts say that there is a correlation between bowel cancer and the high dietary intake of animal fat and protein. It is possible that the putrefactive bacteria (those that consume protein) may somehow produce carcinogenic compounds from cholesterol and bile salts. But even if this is so, eating lots of yogurt is not likely to be much of a remedy because the bacteria in yogurt don’t colonize in our digestive tract, and yogurt contains animal fat and protein. Where does this leave the health claims about yogurt? Is it good for you even if it doesn’t make you live longer? Is it a good diet food? Let’s look at how yogurt is made. MAKING IT ALL GEL Yogurt is fermented milk, a product that can easily be made at home. From the cook’s point of view, two major changes take place when milk is converted into yogurt: It turns from sweet to sour, and from liquid to a semi-solid gel. These changes are caused by the bacteria Lactobacillus bulgaricus and Streptococcus thermopiles. Cows’ milk contain about 4.8% lactose and the bacteria consumes much of this sugar, producing the sour-tasting lactic-acid, C2H4 9OH COOH. It is this acid that causes protein in the milk to coagulate. Milk contains many types of protein, and it is the type known as casein that is involved in making yogurt. Casein molecules are normally packed into microscopic bundles called micelles. T milk’s normal ph of 6.5, the micelles are dispersed throughout the milk. As the lactic acid builds up, the ph gradually drops to 4.5, and the acid alters the casein molecules so that the micelles link together in chains and clusters. The linked micelles form a semi-solid network known as gel. The other ingredients of the milk, such as vitamins, enzymes, unfermented lactose, fat, water - remain in the spaces of the gel-like protein network. During the conversion of milk to yogurt the amount of lactose is reduced, but the food value of the other components in milk is largely unchanged. Page 2 EAT YOURSELF SKINNY Many dieters have turned to yogurt in response to television advertisements showing stylish and skinny people eating yogurt instead of hamburgers. Some low-fat yogurt is advertised as having only 15 fat. Though true , the implication that it is diet food may be misleading. Some popular brands are low in fat, but added sugar, fruit, and flavorings raise the caloric count. Yogurt has the calories of the milk it was made from, plus the calories of the milk solids that are often added to give it a firmer “body’, plus the calories of any added sugar and fruit. As an eight ounce cup of fruit-flavored yogurt averages about 250 calories, the same as a small salad and an apple. Yogurt is nutritious because it is high in protein, riboflavin, and calcium but compared to other diet foods, it is not especially low in calories. If you are on a diet, be sure to check the calories listed on the label. LACTOSE INTOLERANCE The sugar that is present in milk-lactose is the all important source of energy for nursing calves and babies. Lactose is a disaccharide, a sugar of two rings, that cannot be absorbed into the bloodstream until it has been broken into two smaller sugars by the enzyme lactose (Note that the name of sugars differs from the name of the digestive enzyme by just one letter). The amount of lactose in your body is not constant. It reaches its maximum level in the human intestine shortly after birth, then declines between the ages of 1 ½ an 3 1/s, when babies no longer need to drink milk. For most people. Lactose production ceases by age three. However, due to genetic differences, most people of European ancestry for any location where people drink the milk of cows, goats, yaks, etc. continue producing lactose at a lower level for the rest of their lives. This means that, as adults, they can drink moderate amounts of milk and easily digest the milk sugar. However, some adults can’t drink milk products without discomfort. In the absence of lactose the sugar passes through the intestine without being absorbed and reaches the colon intact. There it nourishes bacteria that produce carbon dioxide and hydrogen. The gases and excess water cause severe abdominal cramps and bloating; the lactose and lactic acid increase osmosis within the colon, leading to water retention and diarrhea. This condition called lactose intolerance, causes real abdominal distress. Lactose intolerance was not recognized by western medical science until the elate 1960s. This relatively late recognition of a common problem is probably because The United States only about 10% of Caucasians of European descent have lactose intolerance, compared to 70% of African-Americans. Most lactose-intolerant adults can consume only a pint of milk per day without intestinal distress, but they can consume larger amounts of yogurt. This is because yogurt contains 25% to 50% less lactose than milk. SHORTFALL Should you eat yogurt? Sure…if you like it. Will it help you loose weight? Perhaps, if you read the label and only buy varieties that have fewer calories than the food you’ve been eating. Is it good for you? You bet--just like milk and fruit. Will it make you live longer? That brings us back to Elie Metchnikoff. Metchnikoff, you recall, was the Russian biologist who popularized the notion that the lactobacilli in yogurt promote longevity and announced that he would live to be 150 years old. He continued to eat yogurt and write books until he died of old age at 71 - just 79 years short of his goal. Gwendolyn D. Evans is a lactose-intolerant freelance writer living in Ellenwood, Georgia, currently from Lithonia, Georgia, who makes her own yogurt. She would like to thank Manfred Kroger, Professor of Food Science at Pennsylvania State University, and Miloslav Kalab, scientist at the Food Research Institute, Agriculture Canada. She extends a thank you to Ida Mae Harris, Toby McNease, and Lawrence Gordon who all lived to be over 100 years old for contributing to her research. The above mentioned people are no longer living but their life span was a remarkable one because they did not eat yogurt. Whether yogurt gives you additional years is still yet to be discovered, but remember it is good for you