Not long ago, doctors, nutritionists and other medical authorities were telling us to take fish oil supplements, or at least start pounding the salmon to get enough omega-3 fatty acids.

Fish oil supposedly helped prevent a range of health issues, from heart disease to eye problems, and was seen as a sort of universal supplement.

That's changing a bit now, for a few key reasons. First, the science is evolving on whether fish oil actually helps prevent a number of diseases and conditions. For example, a large-scale National Eye Institute study - called Age-Related Eye Disease Study 2 (AREDS 2) - has shown fish oil supplements containing omega-3 fatty acids do not alter the progression of age-related macular degeneration.

The institute began 12 years ago funding studies to look at how diet and dietary supplements affect the progression of the disease. Early studies had suggested that fish oil might prevent or slow the progression. The latest results show that fish oil makes no difference in the disease; moreover, neither does beta-carotene, long associated with eye health.

"If you look at all the analysis performed in the (study), it looks like lutein taken with zeaxanthin is at least as effective and may be better than beta-carotene," says Dr. David M. Brown, a retina specialist at the Methodist Hospital who ran Houston's part of the study. "The first AREDS study showed us that vitamins really make a difference in decreasing the complications of age-related macular degeneration. Now, with the AREDS 2, we have solid data on what to recommend to our patients."

And it's not fish oil, at least in this case.

Those considering whether increasing fish oil in their diets would benefit particular health conditions can find reliable data from several reputable sources on the Internet. The Mayo Clinic website, for example, offers an overview of all the diseases and conditions fish oil or omega-3 fatty acids have been alleged to address and assigns a letter grade to the scientific evidence that supports fish oil's benefit to each disease. Earning A grades are heart disease, high triglycerides, hypertension, rheumatoid arthritis and secondary cardiovascular disease. The A grade here means that the scientific evidence is strong for fish oil offering positive benefit for those who suffer these conditions. Dozens of conditions earn a C grade, and a few earn Ds.

More Information


Texas Heart Institute:; click on "Heart Information Center," "Healthy Heart Guide" and "Nutrition."

Memorial Hermann Hospital:; click on "services & specialties" and "Heart & Vascular Institute."

The Methodist Hospital:

American Heart Association:; click on "Getting Healthy."

"Cardiovascular diseases have been well-researched, and this is the main area where we recommend omega-3 fatty acids," says Brook Knox, dietitian at Memorial Hermann in the Texas Medical Center. "People who have strong amounts (of omega-3) have decreased inflammatory processes, decreased triglycerides and decreased heart arrhythmias." Knox notes that some end-stage cancer patients who suffer from high inflammation associated with cachexia (muscle wasting) see positive results from high levels of omega-3.

Many nutritionists advise paying attention to the ratio between omega-3 and omega-6 fatty acids. Both are essential for the body's health; however, the typical American diet is stacked with omega-6 fatty acids, primarily through the many oils and other products used in restaurants. Whereas traditional diets have a more balanced ratio, the American diet often tips the ratio to 10-to-1 or even 20-to-1 in favor of omega-6. "Omega-6 is an essential fatty acid," Knox says. "But the problem is that Americans have way too much of it, and it drives inflammation, so this leads to more chronic illness."

Omega-3, omega-6 and other fatty acids are essential for life and health; yet the body doesn't make them itself-they must come from what we eat. This leads to the second reason why fish oil supplements are not as highly recommended as they were in the recent past. Many doctors and nutritionists are cautious about the use of supplements in general.

"People should try to get everything from food that they can because supplements aren't that well regulated," Knox says. Additionally, even quality supplements can go bad. "In the case of fish oil, the supplement can be of high quality, but the oil can go rancid or oxidize, and this is detrimental to health." The best practice, it seems, for those who are not at high risk for cardiovascular disease or who haven't already suffered a cardiac event, is to get their essential fatty acids from food, not supplements."

"Pills are not a substitute for a good diet," says Dr. Stephanie Coulter who directs the Center for Women's Heart and Vascular Health at the Texas Heart Institute at St. Luke's Hospital. One exception, she says, are people who can't control high triglyceride levels with diet and exercise. For those people, she said, 4 grams of fish oil supplements per day have been shown to reduce triglycerides by 40 percent.

"As adults, we can all protect our hearts against heart disease by eating fatty fish at least twice a week. Fish is a good source of omega-3 fatty acids that are known to benefit the heart of healthy people as well as those at high risk of or who already have established heart and vascular disease," Coulter says. "I routinely recommend the Mediterranean Diet for my patients because it encourages fish and foods high in omega-3 fatty acids."