Despite a recent decrease in the number of people taking it, fish oil supplements remain the third most popular nutritional supplement. But just how firm is the evidence to support their use?
The idea that fish oil and omega-3s are good for your heart has been nutrition orthodoxy for decades. A few dissonant voices have argued that this particular emperor has no clothes. But they have largely been drowned out by the crowd.
Although fish consumption has increased somewhat, most Americans still fall short of the recommended two or more servings of fish per week. And until recently, health experts ranging from Harvard to the American Heart Association have recommended a fish oil supplement for those who aren't eating enough fish, as a way to bridge the gap.
Fish oil supplements are the third most commonly taken nutritional supplement. There have been concerns about possible contaminants in commercial fish oil supplements, as well as the negative effects of over-fishing in order to produce enough fish oil to meet the demand. Even so, the presumed benefits have largely overshadowed these concerns.
But just how firm is the evidence to support taking fish oil supplements?
What's the evidence on fish oil?
Epidemiological studies have found that people who eat more fish and/or take in more omega-3s have lower rates of death from cardiovascular and other diseases. Randomized trials have established that fish oil supplements reduce inflammation and lower triglycerides. But as recently as 2010, authors of a scholarly article on “Fish oil for the Treatment of Cardiovascular Disease” conceded that “The role of omega-3 fatty acids in reducing mortality, sudden death, arrhythmias, myocardial infarction, and heart failure has not yet been established.”
Over the years, trials showing that fish oil supplements do not, in fact, reduce the risk of heart attacks or death have begun to pile up.
That was 2010. Over the years following, trials showing that fish oil supplements did not, in fact, reduce the risk of heart attacks or death began to pile up. In 2018, researchers published the results of a large meta-analysis looking at ten different clinical trials in which people with heart disease (or at high risk of developing it) took either fish oil supplements or a placebo. Overall, they could detect “no significant association with fatal or nonfatal coronary heart disease or any major vascular events” and concluded that there is “no support for current recommendations for the use of such supplements in people with a history of coronary heart disease.”
In November 2020, researchers shared new data from a large, placebo-controlled trial involving over 13,000 people who either had heart disease or were at high risk of developing it. The study involved subjects from 22 different countries and these folks were taking a lot of fish oil: 4 grams per day. Unfortunately, even at that dose, the fish oil appeared to provide no benefit in terms of reducing cardiac events.
But what about people without a history or risk factors for heart disease? Could taking fish oil supplements keep them from developing heart disease? Unfortunately, that is a question that has not been well studied, in part because a trial to test this hypothesis would have to be very long and, therefore, extremely expensive.
It's worth mentioning, however, that the potential benefits of omega-3s are not limited to preventing heart disease. Omega-3s may also play a role in reducing the risk of depression and cognitive decline and can reduce pain and stiffness for people with arthritis and other inflammatory conditions.
A whole foods approach
Personally, I don’t think we’ve overestimated the value of omega-3 fats. But we may have underestimated the benefits of getting our omega-3 from whole foods instead of supplements. After all, the obsession with fish oil and omega-3s began when it was observed that indigenous peoples living in Greenland had much lower rates of heart disease than Danes who lived nearby.
We may have underestimated the benefits of getting our omega-3 from whole foods instead of supplements.
The Greenland Inuit had much higher intakes of omega-3, but not from fish oil supplements. The oily fish that they fished out of the Arctic waters was a staple of their traditional diet. They ate very little red meat or poultry. The nearby Danes, on the other hand, ate much less seafood and a lot more fresh and cured meat.
Giving omega-3 supplements to people who continue to eat a lot of beef or poultry might not have the same effects as replacing some of that meat with fish.
In my 30-Day Nutrition Upgrade program, which many of you have done with me, players earn points for eating fish on a given day but not for taking a fish oil supplement. This is because the benefits of our food choices are often not limited to the nutrients we get from eating those foods.
It also has something to do with what we're not eating because we’re eating those healthy foods instead. If you’re eating grilled salmon for dinner, for example, chances are pretty good that you’re not also eating a hot dog. Not only are you getting the omega-3s and other nutrients that are in the fish, but you’re also not taking in all of the less healthy fats and sodium nitrites in cured meats.
Should you ditch your omega-3 supplement?
High-quality fish oil supplements are not inexpensive, and the return on investment isn’t looking so hot these days. If your doctor has recommended that you take a fish oil supplement, you should definitely consult with her before stopping. But if you’re just taking one on the off chance that it might do some good, that money might be better spent on a nice piece of fish two or three times a week. If you don’t like cooking fish at home, order it when you eat (or carry) out! But cooking fish at home is nothing to fear.
Here's a quick video showing one of my favorite ways to prepare fish.