Study highlights:

• In an animal study of heart failure, fish oil supplementation was helpful to animals on a low-fat diet, but not to those on a high-fat diet.
• Researchers think that a high-fat diet may block the heart cells’ ability to absorb the omega-3 fatty acids in fish oil.

DALLAS, July 13, 2009 — Fish oil (EPA & DHA) supplementation helped the heart when paired with a low-fat diet, but not when added to a high saturated-fat diet fed to rats with heart failure, according to a study in Hypertension: Journal of the American Heart Association.

A group of six researchers from different institutions, led by William C. Stanley, Ph.D., from the University of Maryland-Baltimore, hypothesized that when the heart is stressed, such as in heart failure, a high-fat diet may block the heart cells’ ability to absorb the heart-healthy omega-3 polyunsaturated fatty acids (PUFAs) found in fish oil.

The investigators found that heart size – measured by left ventricular mass (LV mass) – increased in rats fed low- and high saturated-fat diets without fish oil by 40 percent and 42 percent respectively. On a low-fat plus fish oil diet, LV mass increased just 4 percent, while the group fed high saturated-fat diet with fish oil saw a 36 percent LV mass increase.

The scientists also found that certain genes associated with heart failure did not get “switched on” in the group fed a low-fat diet supplemented with fish oil.

The researchers conclude, “This suggests that in order to maximize the benefit from fish oil supplementation, patients at risk for heart failure should not consume a high saturated fat diet.”

As part of an overall healthy diet, the American Heart Association recommends limiting saturated fat in the diet to 7 percent or less of calories and consuming fish, especially oily fish, two times per week.
Author disclosures are on the manuscript. The National Institutes of Health funded the study.

###

Statements and conclusions of study authors that are published in American Heart Association scientific journals are solely those of the study authors and do not necessarily reflect the association’s policy or position. The association makes no representation or guarantee as to their accuracy or reliability. The association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific association programs and events. The association has strict policies to prevent these relationships from influencing science content. Revenues from pharmaceutical and device corporations are available at www.americanheart.org/corporatefunding. 

NR09-1086 (Hypertension/Shah-Stanley)