Fish oil supplements have long been touted for their supposed heart health benefits, but a new study casts doubt on that line of thinking.
Millions of Americans choke down large fish oil supplements every day -- coughing up more than $1 billion a year -- based on the belief that the pills can help prevent heart disease.
But now, a large review of research shows no overall heart benefit to taking omega-3 fatty acid, or fish oil, supplements.
There was a small reduced risk for heart-related deaths, but researchers say it wasn't significant.
Other forms of heart disease prevention have been well documented.
"Eating healthfully, exercising is really so much more important than supplement," said Elisabetta Politi, RD, Duke Diet and Fitness Center, Duke University.
According to the Council for Responsible Nutrition, nearly a quarter of all U.S. adults take fish oil pills.
In a statement, the organization suggested the research results were skewed because the "combined studies were not comparable in their design."
But this is the latest in a string of studies finding little to no benefit to supplements. Recent studies have refuted claims that ginkgo biloba can prevent dementia and that vitamin D may lower cholesterol.
Dietitians say it's the synergy of phytochemicals and multiple nutrients in food that makes healthy food - healthy.
"It's not the same to get vitamins and supplements from a pill. It's so much better to get it from food," said Politi.
Omega-3 fatty acids are found naturally in oily fish like salmon and tuna, flax seed and walnuts.
The Nutrition Business Journal says American spending on fish oil supplements grew in 2011 at a rate of 5.4 percent.