The Fishy Science of Omega-3s

Twenty thousand papers later, researchers are still debating whether the fatty acid is all it’s cracked up to be.

A man shovels fish into a barrel.
Robert F. Bukaty / AP

Based on all the hype, you’d be forgiven for believing that the fish oils known as omega-3s are the solution to every problem. Heart disease, dementia, depression, even obesity—the list of ailments that experts claim a daily dose of omega-3 can help prevent seems endless. And with more than 10 percent of Americans taking a capsule of fish oil daily, omega-3s are one of the most profitable supplements in the world, too. Listen in this episode, as the author Paul Greenberg and the scientist JoAnn Manson help us figure out what these supposedly miracle molecules are, and what consuming them is doing to our bodies—and to our oceans.

Greenberg had already authored a couple of successful and award-winning books about fish by the time he hit his mid-40s—an age when he, like many people, started to feel the first, faint signs that he was no longer young. “When you Google all the things that are going wrong with you in middle age—your joints hurt, your high blood pressure, losing your memory—what comes up again and again are omega-3 supplements,” he told Gastropod. Greenberg knew that those supplements are made from fish—millions of tiny fish that no one eats, such as the menhaden and the Peruvian anchoveta. And so he set out to write his most recent book, The Omega Principle, which follows fish oils from their evolutionary origins at the dawn of photosynthesis to their discovery by a Spam scientist to the enormous extraction industry that feeds our hunger for them today.

The secret to omega-3s’ success lies in their chemical structure, which makes them more flexible and dynamic than other fatty acids. That means they show up anywhere that needs to move or transmit signals rapidly—hummingbird wings, sperm, and, especially, the human brain. Experiments in the 1930s proved that fatty acids, including omega-3s, were essential for life, but until relatively recently, they were mostly studied by scientists looking to extend the shelf life of processed foods, as the dynamism of omega-3s’ chemical structure also gives them a tendency to go rancid quickly. Then, in the 1970s, two Norwegian researchers published a paper linking low rates of cardiovascular disease among the Inuit to their elevated consumption of omega-3s.

Since then, more than 20,000 papers have been published examining their health benefits—but, according to Manson, who’s an epidemiologist at Harvard, many of those studies were flawed. She’s the lead researcher on the first large-scale, randomized clinical trial of the efficacy of omega-3s in preventing cancer, heart disease, and stroke in the general public. Her Vitamin D and Omega-3 Trial (VITAL) study launched in 2010, and recently published its first results—which Manson shared with us in this episode.

So, are omega-3s really the key to a healthy old age? And if we should be consuming more omega-3s, then how much, and in what form? From cod-liver oil to cardiovascular risk, listen in this episode for the history and science of America’s favorite fatty acid.

This post appears courtesy of Gastropod.