~Note: this research study is from 2003. Old news. Still relevant.~Regular fish consumption reduced the risk of heart disease by as much as 64% in diabetic women, according to
a 2003 study in “Circulation.”The results confirm previous findings suggesting frequent fish intake is beneficial for heart health in the general population. What set this study apart was that it assessed the relationship between fish and heart health in diabetic women, who have high heart disease risk.
“12.6 million, or 10.8% of all women aged 20 years or older have diabetes,” according to the
American Diabetes Association. This study looked at type 2 diabetes specifically, the most common form among Americans. After eating, the body breaks down sugar from food into fuel for the body’s cells. Type 2 diabetes prevents that fuel from being delivered to cells, leading to complications including: blindness, kidney disease, amputations, and heart problems, among others. “Adults with diabetes have heart disease death rates about 2 to 4 times higher than adults without diabetes.”
The study team, led by
Dr. Frank Hu of the Harvard School of Public Health, followed 5103 women who had or developed physician-diagnosed type 2 diabetes from 1980 to 1996. Diabetic women who had already experienced heart disease before the start of the study were excluded. Heart disease included heart attack, stroke, blocked arteries, chest pain, and irregular heart beat.
These women were a subset of the larger
Nurses’ Health Study, which has sent health questionnaires to 121,700 female registered nurses biennially since 1976. These surveys collect information on medical history, lifestyle, eating habits, and newly diagnosed illnesses. From looking at these, Dr. Hu’s team was able to find out how much fish participants ate over 16 years and if heart disease or death happened.

The women were divided into five groups depending on how often they ate fish: less than once a month, one to three a month, once a week, two to four a week, and five or more times a week. Investigators reported 362 new cases of heart disease and 468 deaths. Compared to diabetic women who rarely ate fish (less than once a month), the risk of heart disease reduced by 30% for women who ate fish one to three times a month. 40% for women who ate fish once per week. 36% for women who ate fish two to four times a week. And finally, 64% for women who ate fish five times a week. Higher fish intake was also associated with significantly lower death rates; ranging from 25% reduced risk (1-3 fish/month) to 52% reduced risk (5 or more/week).
Hu concedes the self-report nature of the questionnaires to be a limitation of the study. He further allows that lifestyle could influence results. Participants with a culinary affinity for fish, also ate more fruits, vegetables, and lean meat. Participants taking aspirin could have improved blood flow thanks to the medication. He backs his results nevertheless. Whether or not investigators took these variables into account in their statistical analyses, it did not appreciably alter findings.

The
American Heart Association recommends adults, barring pregnant women, consume at least two servings of fish weekly. Fish are rife with fish oil (aka omega-3 fatty acids), especially fatty fish like salmon, mackerel, tuna, and herring. Omega-3 fatty acids improve blood vessel function, reduce blood clot formation, decrease circulating fats in the blood, and stabilize irregular heartbeats. Consuming more fish could yield significant health gains for those with, or at high risk of heart disease or diabetes. While not assessed in this study, fish oil capsules, with your doctor’s blessing, could conceivably offer an alternative for those who dislike eating fish.
Hu F. Rish and Long-Chain ω-3 Fatty Acid Intake and Risk of Coronary Heart Disease and Total Mortality in Diabetic Women. Circulation. January 2003; 107:1852-1857.