AHA Advisory Recommends Fish Twice Weekly for CV Health

Megan Brooks

May 24, 2018

In an updated scientific advisory, the American Heart Association (AHA) reaffirms advice that adults consume fish two times per week to help reduce the risk for congestive heart failure, coronary heart disease, sudden cardiac arrest, and ischemic stroke.

Specifically, the AHA recommends eating two 3.5-ounce servings of nonfried fish (or about three fourths of a cup of flaked fish) per week, preferably oily fish such as salmon, mackerel, herring, lake trout, sardines, or albacore tuna, which are all high in omega-3 fatty acids.

One serving of fatty fish, such as salmon, per week provides the recommended approximately 250 mg daily intake of long-chain n-3 polyunsaturated fatty acids (PUFAs), whereas multiple servings of lean fish, such as cod, are required to achieve the recommended intake, the advisory notes.

The advisory, written by a panel of nutrition experts, was published online May 17 in 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," Eric B. Rimm, ScD, chair of the AHA writing group and professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health in Boston, Massachusetts, said in a news release.

The advisory notes that in 2012, the average seafood intake in the United States was about 1.3 servings per week, up modestly from 1.1 servings per week in 1999, but still well below the current recommendations.

The currently available evidence is consistent with a beneficial role of dietary long-chain PUFAs on "triglycerides, cardiac electrophysiology, endothelial function, and possibly blood pressure and inflammation, although the evidence for each of these end points is more limited for dietary as opposed to supplement sources," the advisory says.

The advisory also addresses concerns about mercury in fish. Mercury is present in most seafood but in higher concentrations in large fish, such as shark, swordfish, tilefish, king mackerel, bigeye tuna, marlin, and orange roughy.

While mercury contamination may be associated with serious neurologic problems in newborns, existing evidence shows that mercury contamination does not have harmful effects on heart disease risk in adults, and the benefits of eating fish outweigh the risks associated with mercury contamination, especially if a variety of seafood is consumed, the advisory concludes.

The advisory also touches on the subject of farmed fish, given that the capture of wild-caught fish species has leveled off and the productivity of farmed fish "continues to grow."

It recommends that increases in fish farming be monitored to ensure that farming systems are "sustainable and environmentally appropriate" and that farmed fish have long-chain PUFA levels on par with those of wild-caught fish.

The new advisory is consistent with the AHA 2020 Impact Goals that recommend including seafood as part of the healthy dietary pattern goals, as well as 2015 AHA diet and lifestyle recommendations.

As for fish oil supplements, a 2017 AHA science advisory recommended against omega-3 fish oil supplements for the general public to prevent clinical cardiovascular disease because of a lack of scientific evidence regarding any effect on cardiovascular risk. 

However, the advisory noted that fish oil supplements may help prevent death from heart disease in patients with recent MI and may prevent death and hospitalization in patients with heart failure. 

Rimm has no relevant financial disclosures. Disclosures for the writing committee are listed in the paper.

Circulation. Published online May 17, 2018. Abstract

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