Among dietary supplements, fish oil is one of the most popular, its softgel tablets found everywhere from natural food stores to Target.
Fish oils contain omega-3 fatty acids, which are necessary for normal growth and development. Omega-3 fatty acids are highly concentrated in the brain, leading to assertions of their influence on memory and brain performance.
But consumers may want to rethink popping fish oil pills if they're hoping those supplements full of omega-3 fatty acids will keep their brains healthy.
Researchers at the National Institutes of Health found that omega-3 supplements did not slow cognitive decline in older people.
The study joins a growing body of medical research that questions some of the health claims made by proponents of fish oil.
Many believe, for example, that omega-3 fatty acids will protect against heart disease, but there isn't clear evidence they lower the risk of heart attacks and stroke.
"Contrary to popular belief, we didn't see any benefit of omega-3 supplements for stopping cognitive decline," said study author Emily Chew, deputy clinical director at the National Eye Institute, which is part of the National Institutes of Health.
A much better bet for all-around brain and heart health, she said, is eating food naturally high in omega-3 fatty acids, such as salmon, flaxseed and walnuts.
Fish oil is more popular than several other well-known natural products, like melatonin, echinacea and garlic supplements.
Scientists are curious about other potential benefits. Researchers are studying omega-3 fatty acids to see if they may help relieve symptoms of depression, rheumatoid arthritis and dry eye syndrome.
Dr. Emily Chew specializes in eye diseases. For more than two decades, she's been studying whether the daily intake of certain vitamins and minerals could reduce the risk of cataract and advanced age-related macular degeneration, or AMD.
The authors of the study acknowledged its limitations, saying more research is needed to see if taking supplements earlier in the development of brain-related diseases like Alzheimer's would make a difference.
