Omega-3 in Fish Oil Doesn't Prevent Heart Disease, New Study Claims

Salmon sits for sale at a market in August 2013 in Washington, D.C. A decade-long analysis of fish oil studies found that increased intake of omega-3 fatty acids have little to no effect on cardiovascular health as many public health agencies claim. (Photo by Saul Loeb/AFP/Getty Images)

Consumers have widely adopted omega-3 fatty acids as a preventative measure for heart attack and stroke, though most research has failed to prove causation. A new longitudinal study suggests fish oil more closely resembles snake oil than a nutritional supplement.

In an analysis spanning 10 years, four continents and more than 112,000 participants, researchers found omega-3 supplements had no effect on cardiovascular health, suggesting that the evidence backing the fish oil industry—worth $2.25 billion dollars in the U.S. alone—is baseless.

The paper, published in July in the Cochrane Database of Systematic Reviews, examined how increased intake of omega-3 fatty acids that occurred naturally in fish and plants or produced in pills affected participants' risk of heart attack, stroke and death.

The Mayo Clinic previously reported the unsaturated fatty acids found in "oily fish" like salmon and tuna reduce inflammation throughout the body, which lowers one's risk of heart attack and stroke. Eating one to two servings of fish per week was said to significantly slash the likelihood of cardiovascular disease.

But researchers found that fish oil consumption had little to no impact on all-cause mortality as well as risk of heart attack or stroke: the difference in risk of death was only 0.2 percent less for people who regularly consumed omega-3.

The results showed a slight correlation between ALA, a type of omega-3 fatty acid found in plants and nuts, and improved circulation and cardiovascular health, lead author Lee Hooper said. But the effect was weak: at least one thousand people would need to increase their intake to prevent just one person from dying of cardiovascular disease.

The study didn't address the neurological benefits of omega-3, which has been proven to bolster brain function and protect against neurodegenerative diseases like Alzheimer's and Parkinson's. Healthy fats like omega-3 are essential nutrients used to build cell membranes and protect nerves, but the body can't produce it on its own, so people rely on sources like oily fish, leafy greens and nuts to fill their intake.

First used as an 18th-century curative in European fishing communities, it gained medical attention in a study from the early 1970s that associated low cardiovascular disease among Inuit populations in Greenland with their omega-3-heavy diet. Despite difficulties in proving fish oil as a direct cause of the heart-healthy anti-inflammatory response and inconsistencies in measuring omega-3 levels in blood before and after testing the supplement, consumer demand for fish oil pills boomed. Now, nearly 10 percent of Americans take the supplement, according to the National Center for Complementary and Integrative Health.