Should we take omega-3 supplements or eat 2 servings of omega-3-rich fish a week, as recommended by the American Heart Association? The studies on this subject are numerous and their conclusions are unclear, especially when it comes to the risk of prostate cancer. A team from the Intermountain Healthcare Heart Institute (Salt Lake City) has continued research into the benefits and risks of such supplementation, in particular, the possible increase in the risk of prostate cancer. The findings, presented at the scientific meeting of the American Heart Association (AHA) in 2019, confirm that there is no link between elevated plasma levels of omega-3 and increased cancer risk. On the other hand, the cardiac benefits are confirmed, even in the case of pre-existing coronary artery diseases.
In 2013, a study* was published in the journal of the national cancer institute that suggested a possible link between high plasma levels of omega-3 and the development of aggressive prostate cancer. Other studies yielded mixed results on this risk. Several studies have also shown the benefits of omega-3 for the prevention of other cancers. The question is, therefore, whether the recommendation of omega-3 to patients, who have been shown that it can benefit their heart health (and cognitive health), does not expose them to an increased risk of prostate cancer.
Omega-3 levels do not seem to increase the risk of prostate cancer
In a first study, the researchers identified 87 patients who developed prostate cancer. These patients were also tested to determine their plasma levels of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), 2 common omega-3 fatty acids. These data were compared with a control group of 149 participants, free of prostate cancer. The analysis concluded that high levels of omega-3 are not associated with an increased risk of cancer.
Omega-3 appears to be beneficial for survival even in cases of pre-existing coronary artery disease: a second study examines data from 894 patients with no history of myocardial infarction or coronary artery disease and referred them for coronary angiography. The analysis showed that about 40% of these patients have severe coronary artery disease and about 10% in the three major coronary arteries. The researchers measured plasma levels of omega-3 metabolites (including DHA and EPA) and followed these participants in the incidence of cardiovascular events (heart attack, stroke, heart failure or death). The analysis confirmed that patients with high levels of omega-3 metabolites had a lower risk of adverse events during follow-up, whether or not they were diagnosed with a serious disease during the first angiogram.
The study is thus the first to assess how omega-3s can help patients who have already developed cardiovascular disease. The results confirm that regardless of the cardiovascular risks that a patient may have, omega-3 levels are inversely proportional to the risk of future cardiac events.