A new scientific advisory reaffirms the American Heart Association’s recommendation to eat fish—especially those rich in omega-3 fatty acids—twice a week to help reduce the risk of heart failure, coronary heart disease, cardiac arrest, and the most common type of stroke (ischemic). The advisory is published in the American Heart Association’s journal Circulation.

“Since the last advisory on eating fish was issued by the Association in 2002, scientific studies have further established the beneficial effects of eating seafood rich in omega-3 fatty acids, especially when it replaces less healthy foods, such as meats that are high in artery-clogging saturated fat,” said Eric B. Rimm, ScD, chair of the American Heart Association writing group and professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health in Boston.

The Association recommends eating two 3.5-ounce servings of non-fried fish, or about a ¾-cup of flaked fish every week. Emphasis should be placed on eating oily fish like salmon, mackerel, herring, lake trout, sardines, or albacore tuna, which are all high in omega-3 fatty acids.

The advisory was written by a panel of nutrition experts, who also reviewed studies about mercury in fish. Mercury is found in most seafood, but is prevalent in large fish, such as shark, swordfish, tilefish, king mackerel, bigeye tuna, marlin, and orange roughy. The writing group concluded that while mercury contamination may be associated with serious neurological problems in newborns, existing scientific research finds that mercury contamination does not have adverse effects on heart disease risk in adults, and the benefits of eating fish substantially outweigh any risks associated with mercury contamination, especially if a variety of seafood is consumed.

The importance of environmentally sustainable fish farming techniques and other topics are also briefly discussed in the advisory. A previously published American Heart Association advisory on omega-3 fish oil supplements noted that the supplements are not recommended for the general public to prevent clinical cardiovascular disease because of a lack of scientific evidence regarding any effect on cardiovascular risk.