The skinny on dietary fat: balance it, don't avoid it
January 10, 2000
Web posted at: 12:22 PM EST (1722 GMT)
By Camille Mojica Rey
Low-fat foods continue to sell briskly, as many consumers try follow a heart-healthy diet, but nutrition professionals advise that a better mix of the types of fat may be more important than strictly limiting all fat.
Scientists have repeatedly found that a diet high in omega-3 fatty acids can help prevent heart disease, diabetes and obesity, and even ease arthritis pain. On the other hand, people who have diets that are low in omega-3s and high in another fatty acid, omega-6 -- the typical American diet -- have higher rates of heart disease. "It's not so much that omega-6s are bad for us, it's just that the ratio is out of whack," says Elizabeth Somer, M.A., R.D., author of "The Nutrition Desk Reference.
Hanging in the balance
An examination of other cultures offers some evidence of this. Japanese, European and Mediterranean diets typically have two-to-one ratios of omega-6 to omega-3 fatty acids, says Artemis Simopoulos, M.D., co-author of "The Omega Diet." In the United States, the ratio of omega-6 to omega-3 fatty acids in diets is about 20 to 1 -- much too high for a healthy lifestyle, leaving Americans susceptible to heart disease, obesity, auto-immune diseases and diabetes. "Since 25 percent of the people in this country don't eat any fish, and few people eat green leafy vegetables, you can see why we have a lopsided ratio," Simopoulos says. At a conference in April 1999 at the National Institutes of Health, Simopoulos and other experts from around the world reached a consensus that a ratio greater than four to one is unhealthy.
Achieving a healthy ratio
So just how do people stack the odds -- or the ratio -- in their favor? It's as simple as cutting down on foods that are rich in omega-6s and eating more foods abundant in omega-3s. That means avoiding foods fried in vegetable oils such as corn and safflower, and eliminating processed foods, many of which contain omega-6s. Other sources of omega-6 fatty acids include meats, seeds, nuts and grains. At the same time, boost the amount of omega-3s in your diet by eating more cold-water marine fish, such as salmon and mackerel, as well as green leafy vegetables. And use canola oil instead of vegetable oil for cooking.
Supplements work, too
For people who don't have access to omega-3-rich foods (or don't like fish), fish oil supplements are now an option. Previous studies indicated that fish oil supplements could pose a danger, but a recent study by William Connor, M.D., of Oregon Health Sciences University, shows that people can safely take up to eight grams a day. Getting omega-3s from natural food sources, however, should always be the first option, says Connor, who presented his research at the 1999 annual meeting of the American Dietetic Association (ADA).
"It's better to eat food than take supplements," says Connor, who recommends people get two grams of omega-3 oil every day in order to reap its protective benefits. (Four ounces of salmon contains 2.3 to 3.6 grams of omega-3s, and four ounces of rainbow trout contains about one gram.) More reason for omega-3s
Omega-3 fatty acids may also be an important component of the central nervous system, says Carol J. Lammi-Keefe, Ph.D., head of the nutritional sciences department at the University of Connecticut, who also presented her research at the ADA meeting.
In her study, Lammi-Keefe and her colleagues found that infants born of women with more omega-3s in their diet during pregnancy had more developed central nervous systems. The study results point to the possible role omega-3s play in the development and maintenance of the nervous system, says Lammi-Keefe, who recommends that pregnant women eat at least three servings of omega-3-rich fish every week.
Lammi-Keefe also plans to look into whether omega-3s are important in preventing memory loss and stemming the effects of Alzheimer's and other diseases related to the nervous system.
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