Are Vitamin D and Fish Oil Supplements Worth It? A New Study Says No

If you're banking on vitamin D or omega-3 fatty acids to prevent a stroke or cancer, it's time to save your money. Now, the largest clinical trial is being conducted in Canada, which is effective in stopping cancer or heart-related conditions.

For years, researches that people with low levels of vitamin D or those who eat less fish may be at greater risk for developing heart problems or cancer. But these studies were mostly observational, meaning researchers simply spotted patterns in a sample of people. This new data comes from a controlled clinical trial where nearly 26,000 people received either the supplements or a placebo. Published in The New England Journal of Medicine, the paper concludes that omega-3 fatty acids and vitamin D are not any better than placebos in preventing cancer or cardiovascular conditions such as heart attacks, strokes or death from heart-related problems.

Although the study authors concluded that vitamin D and fish were used in cancer prevention or overall cardiovascular disease, they did find that omega-3 fatty acids can lower the risk of heart attack by 28 percent in healthy adults. And they saw that African-Americans who took daily omega-3 fatty acids reduced their risk of heart attack by 77 percent.

So with that positive news, why are the supplements still considered unhelpful? Dr. Clifford Rosen, MD of the Maine Medical Research Center MensHealth.com that you can not just slice that good news and act on it.

It comes down to "a whole different statistic approach," Rosen explains. The study was designed to look at major cardiovascular events, which includes a variety of conditions like heart attack or stroke. But when you start pulling out separate cardiovascular conditions, like heart attacks only, it is an entirely different statistical analysis and testing needs to be done, he says.

"It should be tested in a larger formalized trial," he explains. "It may be some possibilities, I think the fish oil is still in the air," Rosen says.

Not so for D. In an accompanying editorial, Rosen said he thinks the door is closed for that vitamin. In other words, it is not worth taking care of heart-related conditions and cancer, which is what this study investigated. But there's a chance it could be useful for other reasons.

What if you've had your D levels tested and they're low? You might need more testing Rosen believes that these conditions may be important, such as bowel or liver diseases, may be the root of low vitamin D levels.

Instead of one supplement, Rosen advises everyone to focus on the science-backed pillars of good health: exercise and eating plenty of fruits, vegetables, nut, and yes, fish.