Does Milk really do your Body Good? [الأرشيف]

Houssam

10-07-05, 02:26 AM

<H2 style="MARGIN: 0in 0in 0pt">Milk: Does it really do a body good?</H2>
Critic questions impact on heartburn, digestion
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<H4 style="MARGIN: auto 0in"> By Emma Hitt</H4>
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It’s well accepted that milk is one of the best dietary sources of calcium, and drinking it can help maintain strong bones and teeth. But what about the benefits of milk for quenching heartburn as the old wives’ tale would have you believe? The evidence for this seems to be less clear. 
"Milk contains calcium in a form that neutralizes acid," says Dr. Nevin S. Scrimshaw, professor emeritus with the Massachusetts Institute of Technology and senior adviser to the Food and Nutrition Program at the United Nations. According to Scrimshaw, the calcium present in milk neutralizes acid reflux into the esophagus and provides almost instant relief in the same way that calcium tablets do. One Tums tablet, for example, has about 200 mg of calcium compared with a glass of milk, which has about 300 mg. 

Neutral about calcium
However, dairy-industry critic Robert Cohen strongly disagrees about the long-lasting benefits of milk for quelling heartburn. In fact, milk can worsen the problem, he says. 
Cohen is executive director of the Dairy Education Board, which is described on its Web site as "a public information association that has been formed to let America know that cow's milk is not nature's perfect food for people." According to Cohen, who is not a research scientist but claims to have performed scientific research in the area of brain hormone chemistry (neuroendocrinology), milk has a buffering effect on gastric acidity. It will alleviate heartburn in the short term, but the buffering effect takes away the ability for the stomach to digest food, he says 
"The normal acidity of the stomach should be a strongly acidic pH of about 1.8. Drinking a 12-ounce glass of milk buffers it up to about a pH of 6.0, so that the contents of the stomach will not be digested," Cohen says. "This phenomenon works well for infants digesting their mother’s milk, which contains acid-sensitive antibodies that are supposed to survive digestion, but in adults, drinking a glass of milk causes the contents to putrefy for the next 3-4 hours, causing reflux," he says. 
"Clearly, though, further research into this issue is needed," he adds.
Melissa Joy Buoscio, a registered dietician and spokesperson for the National Dairy Council, notes that both the calcium and protein found in milk can help buffer stomach acid. But she points out that milk is no longer thought of as a treatment for heartburn because current medications (including proton pump inhibitors such as Nexium, Prevacid and Prilosec) have proven more effective than dietary sources for blocking stomach-acid production. 

Multiple causes of stomach upset 
"Different people report different symptoms of stomach upset and also different methods of relief, and this may be due to the variety of conditions that can cause stomach problems," notes Buoscio. 
Complaints involving the digestive system include gastroesophageal reflux disease (GERD), which is marked by frequent heartburn and/or acid regurgitation. Another disorder is irritable bowel syndrome (IBS) which is defined by at least 12 weeks of abdominal pain or discomfort and altered bowel activity over a 12-month period. 
Symptoms of lactose intolerance (often confused with those of IBS) include nausea, cramps, bloating, gas and diarrhea. They begin about 30 minutes to 2 hours after eating or drinking milk or milk products. The severity of symptoms varies depending on the amount of lactose each individual can tolerate. As many as 75 percent of all African Americans and American Indians and 90 percent of Asian Americans are lactose intolerant, according to the National Institute of Diabetes and Digestive and Kidney Diseases. 

Fat content — less is more, depending 
The fat content of milk is also an issue to consider. "Lower-fat milk appears to be better tolerated in patients with GERD; however, higher-fat milk may be better tolerated in some individuals with lactose maldigestion due to the fact that digestion time is delayed which gives the available lactase enzyme more time to work," according to Buoscio. 
In addition, Scrimshaw maintains that low-fat products are preferable because the principal fatty acid in milk fat, myristic acid, is the most atherogenic (likely to cause atherosclerosis) of all the fatty acids that make up fats, although milk continues to be an excellent source of protein, calcium, riboflavin and is enriched with vitamins A and D. 

Emma Hitt, Ph.D., is a writer specializing in science, technology and medicine.