Fish oil supplements did not prevent heart problems in people who hadn’t had a heart attack yet, in a large long-term study from Italy.
The study - a gold-standard randomized, controlled trial - tested the effect of omega-3 fatty acids, which are found in oily fish such as tuna or sardines. Patients in the study had risk factors for heart disease, such as high blood pressure, High cholesterol, a history of smoking or narrowed arteries. But patients who had a heart attack in the past weren’t allowed to enroll.
Five years after the study began, 11.7 percent of the 6,244 patients taking a capsule containing one gram of fish oil daily had died or been hospitalized for heart problems, compared to 11.9 percent for the 6,269 volunteers who instead received one gram of olive oil every day as a placebo.
The result, reported in the New England Journal of Medicine on Wednesday, is in sharp contrast to other research suggesting that omega-3 fatty acids can help those who have survived a heart attack or suffer from heart failure.
For people who haven’t had a heart attack, though, the new findings “provide no evidence of the usefulness of (omega)-3 fatty acids for preventing cardiovascular death or disease,” according to the research team, led by Dr. Maria Carla Roncaglioni of the Mario Negri Institute for Pharmacological Research in Milan.
She told Reuters Health in an email that the finding argues against the use of fish oil supplements, at least among Italians, who are already exposed to the Mediterranean diet. “There is no reason to prescribe fish oil supplementation unless they have a heart attack,” she said.
Will Aspirin Prevent Your First Heart Attack?
Aspirin does prevent heart attacks and stroke. However, aspirin also increases your risk of severe stomach bleeding. The chances of preventing a heart attack and experiencing a dangerous stomach bleed is about equal. So, the benefit of aspirin for heart attack or stroke is questionable.
The major reason to give aspirin is to prevent heart attacks and strokes, and in healthy people this benefit is outweighed by the risk of bleeding. Aspirin is not the same as statins, which are known to reduce mortality in primary prevention. Aspirin doesn’t affect atherosclerosis; it modifies plaque rupture, which is the final step. That is why it works better in patients with established heart disease.
But, if you’ve suffered a heart attack or stroke before, or are taking medications for diabetes, aspirin’s positive effect on heart health is may be greater than it’s negative effect on stomach health.
The researchers did see a reduction in hospital admissions for heart failure and a preventive effect in women, but “both may be due to chance, although they are consistent with two findings from other studies,” the researchers said.
Alice Lichtenstein, from Tufts University in Boston and a spokeswoman for the American Heart Association, told Reuters Health the findings from the new study are further evidence that, in general, “just giving a supplement on top of a non-heart-healthy lifestyle doesn’t seem to help.”
“We thought vitamin E pills were going to be the answer and that turned out to be wrong. We though beta carotene as an antioxidant was going to reduce cardiovascular disease . . . and that pill didn’t work,” she said in a telephone interview. “It’s the whole package, not just popping one pill.”
Fish oil can be obtained from eating fish or by taking supplements. Fish that are especially rich in the beneficial oils known as omega-3 fatty acids include mackerel, tuna, salmon, sturgeon, mullet, bluefish, anchovy, sardines, herring, trout, and menhaden. They provide about 1 gram of omega-3 fatty acids in about 3.5 ounces of fish.
Fish oil supplements are usually made from mackerel, herring, tuna, halibut, salmon, cod liver, whale blubber, or seal blubber. Fish oil supplements often contain small amounts of vitamin E to prevent spoilage. They might also be combined with calcium, iron, or vitamins A, B1, B2, B3, C, or D.
Fish oil is used for a wide range of conditions. It is most often used for conditions related to the heart and blood system. Some people use fish oil to lower blood pressure or triglyceride levels (fats related to cholesterol). Fish oil has also been tried for preventing heart disease or stroke. The scientific evidence suggests that fish oil really does lower high triglycerides, and it also seems to help prevent heart disease and stroke when taken in the recommended amounts. Ironically, taking too much fish oil can actually increase the risk of stroke.
Fish may have earned its reputation as “brain food” because some people eat fish to help with depression, psychosis, attention deficit-hyperactivity disorder (ADHD), Alzheimer’s disease, and other thinking disorders.
Some people use fish oil for dry eyes, glaucoma, and age-related macular degeneration (AMD), a very common condition in older people that can lead to serious sight problems.
The patients in the Italian study were treated by 860 general practitioners throughout the country. Their average age when they enrolled in the study was 64 years old.