In the American tradition of overdosing on vitamins in pill form instead of eating actual foods packed with the nutrients themselves, fish oil is one of our favorite go-to accompaniments to our disgusting junk food habit. In fact, it's become the third-most ingested supplement in the U.S., presumably because we believe it's doing something. Turns out, it's not.

According to a report in the Well blog at the New York Times, fish oil has long been praised for improving heart health and reducing the risk of stroke, when neither of those things are exactly true.

From 2005 to 2012, at least two dozen rigorous studies of fish oil were published in leading medical journals, most of which looked at whether fish oil could prevent cardiovascular events in high-risk populations. These were people who had a history of heart disease or strong risk factors for it, like high cholesterol, hypertension or Type 2 diabetes.

All but two of these studies found that compared with a placebo, fish oil showed no benefit.

If we can't trust Big Vitamin, who can we trust?

Sure, the omega-3s that you find in your fish oil supplement may logically appear to contribute to a reduction in heart disease and blood clots. As the Times puts it, "Omega-3s can also reduce inflammation, which plays a role in atherosclerosis." Yeah, okay, that's one thing. But in large-scale studies fish oil contributes to that cause very negligibly. Most of our info on the stuff is completely out of date, having been set into the vitamin canon during studies of the late 90s, when our understanding of cardiovascular health was very different. You gotta be kidding us:

"But since then, there has been a spate of studies showing no benefit," said Dr. James Stein, the director of preventive cardiology at University of Wisconsin Hospital and Clinics. Among them was a clinical trial of 12,000 people, published in The New England Journal of Medicine in 2013, that found that a gram of fish oil daily did not reduce the rate of death from heart attacks and strokes in people with evidence of atherosclerosis.

The chief of preventive medicine at Brigham and Women's Hospital in Boston, Dr. JoAnn Manson, claims that the jury is still out, and that fish oil could helpfully contribute to prevention of other diseases such as cancer and depression. But for now, maybe just eat a fatty fish or two.

Image via Shutterstock. Contact the author at dayna.evans@gawker.com.