EPA and DHA are found in oily fish like tuna or salmon.

SALT LAKE CITY — Intake of two kinds of omega-3 fatty acids may be associated with reducing coronary heart disease risk, with a greater benefit observed among higher-risk populations in randomized controlled trials, according to a meta-analyses appearing in the January issue of Mayo Clinic Proceedings.

The meta-analysis estimated the effect of eicosapentaenoic acid and docosahexaenoic acid (EPA+DHA) from foods and supplements. Researchers investigated 18 randomized controlled trials, which included 93,000 people, and 16 prospective cohort studies, which included 732,000 people, that covered the years 1947 to 2015. A grant from the Global Organization for EPA and DHA Omega-3s (GOED), Salt Lake City, supported the study, which may be found here.

A 6% reduced risk of any coronary heart disease, which was not statistically significant, was observed among randomized controlled trials. A statistically significant 18% reduced risk of coronary heart disease was observed in the prospective cohort studies.

Dominik Alexander, Ph.D., lead author and principal epidemiologist for EpidStat

“What makes this paper unique is that it looked at the effects of EPA and DHA on coronary heart disease specifically, which is an important nuance considering coronary heart disease accounts for half of all cardiovascular deaths in the U.S.,” said Dominik Alexander, Ph.D., lead author and principal epidemiologist for EpidStat, an Ann Arbor, Mich.-based institute with a staff of epidemiologists, statisticians and scientists. “The 6% reduced risk among R.C.T.s, coupled with an 18% risk reduction in prospective cohort studies, which tend to include more real-life dietary scenarios over longer periods, tell a compelling story about the importance of EPA and DHA omega-3s for cardiovascular health.”

EPA and DHA are found in oily fish like tuna or salmon, dietary supplements and fortified foods, according to the GOED.

The studies were required to report one or more of the following coronary heart disease outcomes: myocardial infarction such as a heart attack (fatal or non-fatal), angina, sudden cardiac death, coronary death and coronary heart disease incidence (for prospective cohort studies). Study populations included non-hospitalized adults over age 18 with and without coronary heart disease but otherwise free of significant disease pathologies not related to coronary heart disease.

The results indicated EPA+DHA reduced coronary heart disease risk among people with triglyceride levels of 150 mg/dL or more in randomized controlled trials but not among people with triglyceride levels within normal limits. It is estimated 25% of Americans older than age 20 have triglyceride levels of 150 mg/dL or more.

Also, a coronary heart disease risk was found in randomized controlled trials among people with L.D.L. “bad” cholesterol levels of 130 mg/dL or more but not for people with L.D.L. cholesterol levels of less than 130 mg/dL. It is estimated 27% of Americans between the ages of 40 and 74 have L.D.L. cholesterol levels of 130 mg/dL or more.

Harry Rice, Ph.D., vice-president of regulatory and scientific affairs for the GOED

“There are important public health implications related to reducing the risk of coronary heart disease, and therefore we are encouraged by the results of this comprehensive analysis,” said Harry Rice, Ph.D., vice-president of regulatory and scientific affairs for the GOED. “It’s also important that the observed risk reductions were even stronger in patient populations with elevated triglycerides and L.D.L. cholesterol levels, two risk factors that affect more than one-quarter of the American population.”