A recent review of almost 80 randomized control trials suggests increased intake of long-chain omega-3 (LCn3) polyunsaturated fatty acids from oily fish have minimal to no effect on mortality or cardiovascular health. Results of the review were published online July 18 in the Cochrane Library.
Researchers have previously suggested omega-3 polyunsaturated fatty acids from oily fish— including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and plant-based alpha-linolenic acid (ALA) are beneficial to cardiovascular health.
“The findings of this review go against the popular belief that long-chain omega 3 supplements, including fish oils, protect the heart," said Lee Hooper, PhD, of the University of East Anglia and Norwich Medical School in Norwich, U.K., in a prepared statement. “This large systematic review included information from many thousands of people over long periods. Despite all this information, we don’t see protective effects. The review provides good evidence that taking long-chain omega 3 (fish oil, EPA or DHA) supplements does not benefit heart health or reduce our risk of stroke or death from any cause.”
The researchers assessed the effects of increased intake of fish- and plant-based omega-3 for all-cause mortality and cardiovascular (CVD) events.
Hooper and colleagues reviewed 79 randomized trials involving more than 112,000 individuals. Twenty-five trials were used as part of the meta-analysis as they were deemed “unbiased.” The trials assessed the impact of increased LCn3 or ALA intake on cardiovascular health, compared to regular or lowered quantities of omega-3.
The meta-analysis showed no significant difference in death rates—8.8 percent of people who consumed LCn3’s died, compared to 9 percent in control groups.
Increased consumption of LCn3 also showed little to no effect on all-cause mortality, cardiovascular mortality, cardiovascular events, coronary heart disease (CHD) mortality stroke or arrhythmias.
While increased ALA intake may slightly reduce the risk of cardiovascular events, CHD mortality and arrhythmias, it showed little to no effect on all-cause mortality, cardiovascular mortality, CHD events. The impact of ALA intake on stroke are unclear.
“This systematic review did find moderate evidence that ALA, found in plant oils such as rapeseed or canola oil, and nuts, particularly walnuts, may be slightly protective of some diseases of the heart and circulation,” Hooper said. “However, the effect is very small, 143 people would need to increase their ALA intake to prevent one person developing arrhythmia. One thousand people would need to increase their ALA intake to prevent one person dying of coronary heart disease or experiencing a cardiovascular event.”
As a senior news writer for TriMed, Subrata covers cardiology, clinical innovation and healthcare business. She has a master’s degree in communication management and 12 years of experience in journalism and public relations.