Jewish World Review April 12, 2002 / Rosh Chodesh Iyar, 5762




Fish & Omega-3 fatty acid consumption and cardiac health

By Robert A. Wascher, M.D., F.A.C.S.

http://www.NewsAndOpinion.com | Two new studies add further evidence that the consumption of fish, or fish oil supplements, can improve the health of your heart.

In the Journal of the American Medical Association this week, the dietary habits of nearly 85,000 women enrolled in the long-term Nurses' Health Study were evaluated and compared with the incidence of coronary heart disease in that group.

Over the course of 14 years, the study's participants were periodically surveyed and examined for interval changes in their health (none of the volunteers had known heart disease upon entering the study).

The respondents were then categorized according to the amount of fish or omega-3 fatty acid supplements in their diet. In the group that consumed fish 5 or more times per week, the likelihood of developing heart disease was 34% less than those who rarely ate fish.

Eating fish 2 to 4 times per week reduced the risk of heart disease by 31%, and even eating fish 1 to 3 times per month reduced the risk of heart disease by 29%. Among women taking supplements of omega-3 fatty acids (the substance in fish that is thought to protect the heart), those taking the highest amounts had a 33% reduction in heart disease risk, while those taking lesser amounts still experienced a significant benefit.

In those volunteers eating fish 5 or more times per week or taking the highest amounts of omega-3 fatty acids, the risk of dying from coronary heart disease was reduced by a very substantial 45%. This study is particularly important, as previous studies involving fish and omega-3 fatty acid consumption and their effects on heart disease have all confined their assessments to men.

While retrospective dietary surveys can suffer from lack of reliability, the power of this study is very high due to the large number of study participants and the carefully controlled conditions of the study.

A related study, the Physicians' Health Study, has been following more than 22,000 physician volunteers over the past 17 years. In this week's New England Journal of Medicine is a report on the impact of omega-3 fatty acid supplements on the risk of sudden cardiac death in this study group, all of whom were without known heart disease.

The study's authors tested the blood of 94 male study volunteers who experienced an episode of sudden cardiac death (but in whom there was no prior history of heart disease) and 184 matched control study participants who did not experience any cardiac events.

Among the men with the highest levels of omega-3 fatty acids in the blood, there was a 72% reduction in the risk of experiencing sudden cardiac death when compared to the men with the lowest levels of these substances in their blood.

The reasons for the protective effects of omega-3 fatty acids are unclear at this time, although there is some evidence that these nutrients can suppress the abnormal electrical rhythms in the heart that can lead to sudden cardiac death. Omega-3 fatty acids are also thought to reduce the levels of the "bad cholesterol" (LDL) in the blood, which is thought to be the primary basis of their coronary heart disease protective effect.

Importantly, both of these studies involved volunteers who initially had no evidence of active coronary heart disease, and encompassed many years of careful follow-up. These two factors make their results especially compelling.

However, large doses of omega-3 fatty acids can adversely affect the body's clotting system, and may increase the risk of bleeding in patients with underlying clotting abnormalities, or in those patients taking certain medications such as anti-inflammatory medications (e.g., aspirin, Motrin, Naprosyn, Indocin, Vioxx, Celebrex, etc.) or blood thinners (e.g., Coumadin, Lovenox, etc.).

At the same time, concerns about the widespread contamination of commercially harvested fish with mercury and other potentially harmful substances may be a compelling reason to consider omega-3 fatty acid supplements. As always, one should first discuss changes in diet and dietary supplements with one's physician.

BRIEFLY

According to the Centers for Disease Control, the costs associated with smoking in the United States exceed $150 billion each year, a 50% increase over previous estimates. Smoking-induced illness and lost productivity account for most of this gargantuan expense. On the average, smoking reduces the lifespan of women by 14.5 years, and by 13.2 years for men. Nearly half a million Americans die prematurely from tobacco-related diseases every single year, making tobacco the single greatest cause of preventable disease and death in our country today.

In the New England Journal of Medicine, a new study has found that circumcision in men reduces the risk of infection with the human papilloma virus (HPV) by 63% in men, and by 58% in women whose partners were circumcised. Although many compelling arguments have been made against routine infant circumcision, this study is important to consider, as virtually all cases of cervical cancer are thought to be caused by chronic HPV infection of the cervix..

The Journal of the National Cancer Institute reports on a study of the implications of race and socioeconomic status on breast cancer treatment and survival. Previous studies have shown that African American women are less likely to receive treatment for breast cancer, and are more likely to die of the disease, when compared to Caucasian women. After evaluating 5,719 women who developed breast cancer in Michigan, the study concluded that socioeconomic status, and not race, was the primary determinant of delayed diagnosis and poorer survival..

The Journal of the American Medical Association reports that St. John's Wort, an over-the-counter "supplement" used by many Americans and Europeans to treat depression, appears to be ineffective in treating major depression when compared with Zoloft, a prescription antidepressant that has been shown to be very effective in treating moderate-to-severe depression.

JWR contributor Dr. Robert A. Wascher is a senior research fellow in molecular & surgical oncology at the John Wayne Cancer Institute in Santa Monica, CA. Comment by clicking here.

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© 2002, Dr. Robert A. Wascher