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.
"Ninety-five percent 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, walnuts and algae are all sources of omega-3s, but they are not a substitute for fatty fish.
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.