In the wellness world, few things are as common and as hard to swallow as advice about vitamins and supplements and their possible benefits.
A study published last month in the journal BMJ Medicine looked at the risk/benefit profile of fish oil on heart health, suggesting, based on a multi-year study, that regular fish oil intake may slightly increase the risk of cardiovascular events, including atrial fibrillation and stroke, in people who were not at high risk.
In people who already had cardiovascular disease, researchers found a benefit from taking fish oil supplements and the progression of the disease.
Fish oil supplements are probably the most common type of omega-3 supplement that people can get over the counter. They often come in capsule form, and people use them because other research has linked omega-3 consumption to potential benefits for a variety of health conditions, including rheumatoid arthritis, cognition, and even issues like ADHD. More recently, studies have linked omega-3 supplementation to reduced anger.
But the fact that fish oil supplementation may not benefit heart health in the general population is “not a new issue, just a new paper on the subject,” Dr. Andrew Freeman, a cardiologist at National Jewish Health in Denver, told CNET.
He added that over-the-counter fish oil supplements are different from the “highly purified” forms of fish oil, including Lovaza and Vascepa, that people can get from their doctors with a prescription to lower triglycerides. (High triglyceride levels contribute to cardiovascular risk.)
While far from the final word on the benefits and risks of omega-3 supplements (there were limitations to this study, including the important fact that people self-reported their fish oil intake, so this research does not reflect dosage), it does raise questions that continue to plague supplement recommendations in general, such as the fact that they are not regulated for safety or effectiveness by the U.S. Food and Drug Administration, and the fact that we are supposed to get the majority of our nutrients from food and diet.
Some diets that emphasize plant-based foods rich in healthy fats, lean protein, and some sources of dietary fish oil (including diets such as the Mediterranean diet) continue to be associated with positive health outcomes. These diets may be rich in omega-3 fatty acids and other nutrients, but it has been difficult to replicate these benefits in supplement form.
Another important caveat is that people take supplements (including omega-3s and fish oil) for a variety of reasons beyond heart health, so advice on how you should take one depends on you, your diet, and your health goals, which may change over the course of your life.
“There’s not a lot of evidence on omega-3 supplements in general,” Dr. Navya Mysore, a primary care physician in New York City, said via email. If someone is interested in adding one to their routine for a health condition, it’s a good idea to consult a doctor before “making a personal decision.”
Learn more: Foods rich in omega-3s offer many benefits for the heart, hearing and overall health
What are the conclusions of the study? Strengths and limitations
The BMJ Medicine study followed more than 400,000 participants, aged 40 to 69, enrolled in the UK Biobank study, tracking their health events and the lifestyle and dietary factors they reported, including whether they regularly took fish oil supplements, their regular food intake and more.
After years of follow-up, researchers found that fish oil supplementation in people who already had cardiovascular disease was beneficial, but in the general population (i.e., those without cardiovascular disease), regular fish oil intake was linked to an increased risk of first heart disease and stroke.
The study’s strengths are its large size and the ability to track the incidence of cardiac events. The researchers also collected information on some factors that can influence heart health, such as smoking, heavy alcohol consumption and overall diet. However, it “did not account for behavioral changes in populations with different cardiovascular profiles,” the researchers wrote. Nor can it account for all the health-affecting behaviors that can influence a person’s wellness choices, which are notoriously difficult to separate and identify as cause or effect.
Additionally, most of the study participants were white, the researchers noted, so the study doesn’t tell us whether the same link might hold for people of other races. And most importantly, it didn’t account for the dosage of fish oil people took or specific brands or types.
Some foods that naturally contain omega-3s include fish and seafood, nuts and seeds, vegetable oils, and some fortified foods.
Who should take this study to heart?
The latest findings shouldn’t make you panic and think that your omega-3 or fish oil pills are heart problems in a bottle. As the study authors pointed out, more research is needed on the link between cardiovascular events and fish oil. This research is part of the ongoing research on the full and complex link between omega-3s and the various health benefits when they are available in supplement form. At least for the general population, much of this research is conflicting or inconclusive.
This study alone is not enough to definitively convince people about the benefits of fish oil, according to Dr. Gregory Katz, a cardiologist at New York University Langone.
“To change clinical practice, only a randomized study can establish cause and effect,” Katz said in an email. “A study like this cannot tell us whether fish oil causes the irregular heartbeat.”
But, he added, “some clinical trials of high-dose omega-3 supplements have shown an increased risk of an irregular heart rhythm called atrial fibrillation,” which increases the risk of stroke.
When asked whether vegan or vegetarian omega-3 supplements would be better — those that come from ALA rather than DHA and EPA — the evidence is also murky, because ALA is a “precursor in the body to DHA and EPA, which are the active omega-3s,” Katz said, adding that the way it’s converted to active omega-3s isn’t as efficient and may “not be that helpful.”
So it all comes down to the same advice: Get your omega-3s (and all other nutrients) from your diet whenever possible. If that’s not possible, ask your doctor about starting supplements or taking extra vitamins. Since people may be interested in taking omega-3s for a variety of health reasons beyond heart health, you should talk to someone who understands your medical history so they can weigh the risks and benefits.
In a large, updated 2023 summary that reviewed the available studies on omega-3s and omega-3 supplements for a range of health conditions, including cardiovascular disease, the National Institutes of Health Office of Dietary Supplements concluded that “consuming fish and other types of seafood as part of a balanced diet promotes heart health, particularly when seafood is eaten in place of less healthful foods.” But the evidence for the protective benefits of supplements for heart health is stronger in people with existing conditions.
The latest discoveries nevertheless bring some essential nuances to food supplements.
“Not everyone is the same,” Freeman said of the latest fish oil study. “Not all medications are the same, and what may seem benign is not always the case.”
