Dietary Supplements: What You Need to Know (cont.)
These are not technically dietary supplements, but are nonetheless a popular category.
Homeopathy, or homeopathic medicine, is a medical philosophy dating back to the late 1700s. It's based on the idea that our bodies have a self-healing response. So, the theory goes, if certain a substance causes a symptom in a healthy person, giving that person a very small amount of the same substance may cure the symptoms.
The National Institute of Health's National Center for Complementary and Alternative Medicine web site notes that studies on homeopathy have been contradictory. Some have suggested the results are similar to a placebo effect, while others have found positive effects that are not readily explained in scientific terms.
"Homeopathics are benign in general because they are so dilute it is unlikely they will cause any harm if used properly," says Grotto. "But the explosion in this category includes cleansers [products marketed as kidney, liver and other organ cleansers] and products that misuse the term and are not really homeopathic."
He cautions users to consult health care professionals, and not to attempt to treat or diagnose conditions that require professional care.
Dietary Supplement No. 9: Vitamins D
Chances are, you are not getting enough vitamin D for good health.
"The current recommendations are not adequate to protect against chronic diseases or prevent osteoporosis," vitamin D expert Michael Holick, MD, tells WebMD. "All evidence suggests that infants and adults can tolerate 1,000 IUs a day as safe, without risk of toxicity.
Holick suggests taking a daily vitamin D supplement or getting safe sun exposure to maintain proper blood levels of vitamin D.
And be sure to eat a variety of foods rich in vitamin D such as fortified milk and cereals, salmon, and tuna. Check with your dermatologist about guidelines for safe sun exposure.
Dietary Supplement No. 10: Fish/animal Oil
"95% of the sales in this category come from fish and not animal oils" says Rea.
Unless a doctor is treating you for heart disease or high triglyceride levels, you should not take fish oil supplements, says Alice Lichtenstein, DSc, Tufts University researcher and chairwoman of the American Heart Association (AHA) nutrition committee.
"Studies show that omega-3 fatty acids are cardio-protective and the basis for the AHA recommendation to consume fatty fish twice weekly," she says. "But the studies do not show that popping a supplement can have the same benefit in healthy individuals." She adds, "There is also a misperception that fish oils can lower cholesterol, but this is not true."
If you don't like fatty fish such as salmon, Lichtenstein recommends eating other kinds of fish such as canned tuna. (Just be sure to avoid any fish that is breaded and fried.)
Foods such as canola oil, soybeans, flax, and walnuts are all healthy foods containing omega-3s, but they are not a substitute for fatty fish, experts say.
Clark will continue to recommend omega-3 fatty acids supplements because "most people don't come near meeting the AHA recommendations for fatty fish twice weekly, and with a heightened fear of mercury levels in all types of fish, people are not coming close to getting enough omega-3 fatty acids in their diets."
Tips for Choosing Dietary Supplements
Experts agree there are some rules of thumb for choosing dietary and nutritional supplements. First, look for trusted brands that have been around for some time.
"There have been issues of dietary supplements being adulterated and contaminated with heavy metals, so choose a respected brand to be sure what is on the label is safe and exactly what is found in the product," suggests Grotto.
Another tip: read the claims carefully. If they look too good to be true, they probably are, says Shoa.
"Products promising to pack on 20 pounds of muscle in a week are not going to deliver because nothing can yield those kind of results," he says.
If you want to take it a step further, check out the studies companies site documenting the effectiveness of the product. Clark recommends consulting the journals International Journal of Sports Nutrition and Exercise Metabolism or Medicine and Science in Sports and Exercise for studies on dietary supplements.
Last but not least, be sure to check with your doctor before taking any dietary supplements, suggests Frankos.
The Dangers of Megadoses
Many consumers go way beyond the daily multivitamin, and take megadoses of dietary supplements. But is more better in this case?
No, experts say. In fact, exceeding the Recommended Daily Allowances for some vitamins and minerals could be dangerous.
"Generally, you should not exceed 100% of the recommendation for vitamins or minerals because these supplements are in addition to the food you eat, and potential toxicities can occur," says Grotto.
Be especially careful with minerals and-fat soluble vitamins A, D, E, and K, which can build up in your system.
Published August 24, 2007.
SOURCES: Institute of Medicine Food and Nutrition Board, Dietary Reference Intakes: "Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride." National Academy Press, Washington, D.C., 1999. Journal of Nutrition, October 2005. Position paper of the American Dietetic Association on Food Fortification and Supplementation, Journal of the American Dietetic Association, August 2005. Michael Holick, MD, PhD, professor of medicine, physiology, and biophysics, Boston University Medical Center. Andrew Shoa, PhD, vice president for regulatory affairs, Council for Responsible Nutrition. Alice Lichtenstein, DSc, director and senior scientist, Cardiovascular Nutrition Laboratory, Human Nutrition Research Center on Aging, Tufts University. Dave Grotto, RD, spokesman, American Dietetic Association; author, 101 Foods That Could Save Your Life. Eduardo Baetti, MD, rheumatologist; Kaiser Permanente. Patrick Rea, editorial director, Nutrition Business Journal. Kristine Clark, PhD, RD, director of sports nutrition, Penn State University. Vasilios Frankos, PhD, Division of Dietary Supplement Programs, FDA. Sarubin A. The Health Professionals Guide to Popular Dietary Supplements, American Dietetic Association, Chicago, IL, 2000. FDA. WebMD Weight Loss Clinic Feature: "Are You Getting Enough Vitamin D?" National Center for Complementary and Alternative Medicine: "Questions and Answers About Homeopathy."
©2007 WebMD Inc. All rights reserved.
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