Despite the taste that lingers from your daily supplement, the touted benefits of fish oil for your cardiovascular system and brain are difficult to ignore.
But, says Paul Greenberg, author of “The Omega Principle” (Penguin Press, July 10, 2018), in a recent interview with NPR’s Terry Gross, these claims may not be based in fact. Not to mention, harvesting fish oil is taking a huge toll on our oceans’ ecosystems.
Bursting the fish-oil bubble
Omega-3s are polyunsaturated fats found in seafood and green leafy vegetables. And while they are a very important part of the human brain (making up between 5 and 10 percent of the brain’s mass), Greenberg says it’s been difficult to prove that omega-3s are as miraculous as supplement companies claim.
“There have been these raft of studies that came out in the last 10, 15 years … that have shown really a very limited effect, especially having to do with heart health,” Greenberg tells Gross. “For example, one was published in the Journal of the American Medical Association back I think in 2012. And they found pretty much no effect on cardiovascular health at all from omega-3 supplements.”
The assumption, Greenberg continues, is that because a percentage of our brain is made up of omega-3s, then wouldn’t it stand to reason that more of this would make our brains better? This assumption, he says, is not borne out by scientific research.
In fact, the majority of the studies done are what Greenberg calls “association studies”—studies that look at people eating fish and assume that because they have such high omega-3 levels and better cardiovascular health, the two must be related.
“But it doesn’t show necessarily that the omega-3s did actually improve your health,” Greenberg explains. “The issue becomes more complicated because people who are generally following an omega-3 lifestyle are generally kind of healthier overall. They tend to eat more vegetables. They tend to eat more fish. They tend to exercise. So it’s hard to say that this one single factor is causing all these positive health things.”
When scientists do go through the process of setting up randomized control trials using placebos and control groups, those trials haven’t been showing very strong effects of omega-3s, “particularly when it concerns heart health,” Greenberg continues.
To supplement or not
So what has Greenberg’s research led him to conclude about fish-oil supplements?
“My impression when talking to health professionals was that, generally speaking, it’s better to get omega-3s in food form, just like it’s better to get many different forms of nutrition in food rather than through a supplement,” Greenberg says. “We evolved to eat whole food. And I truly believe that if you’re going to have omega-3s in your body, you should be having them through your food.”
Plus, he adds, it’s better for our oceans, which have been overfished to meet the market’s supply and demand of fish oil. Omega-3 supplements come from pelagic fish, which are essential to the ocean’s biosphere.
“[The energy] coming from the sun is processed by phytoplankton. These little fish that are used for omega-3 supplements transfer the energy from plankton to larger fish,” Greenberg explains. “So if you overharvest this middle layer of anchovies, of herring, of menhaden—if you take them out of the picture, there’s no way for the energy to be transferred from phytoplankton up to larger predators.”
Listen to the full interview on npr.org.
Photo credit: Eziutka, Thinkstock