Fish Oil Omega-3s: New Research Findings

EPA & DHA: Beyond Heart & Brain Benefits

The long chain fats in fish oil, EPA and DHA, are best known for their cardiovascular benefits. They help guard arteries by quelling chronic inflammation, keeping levels of triglycerides in check, and making vessels more elastic. Factor in their ability to improve electrical communication between heart cells and prevent arrhythmia, and it's easy to understand why omega-3s are a standard part of cardiac care in European countries.

The evidence for an Omega-3 role in fending off mental aging is also increasing [see the February 2007 and December 2006 newsletter issues]. Several new areas of potential benefit for these fatty acids are also emerging: visual, prostate and colon health.

Preventing Retinopathy?

In addition to being studied in the AREDS-2 trial for AMD, the omega-3s may help protect against retinopathy, a deterioration of the retina that affects about 4 million diabetics and 40,000 premature infants. This disease is a 2-part process that starts with a loss of blood vessels. With the vessel loss, the retina becomes oxygen deprived and reacts by spurring new vessel growth. However, the low-oxygen triggered vessels grow abnormally and are malformed, leaky and over-abundant.

Collaborating researchers from the NEI, Harvard, the University of Göteborg in Sweden and other institutions, recently examined the effects of omega-3 and omega-6 in an animal model of retinopathy (1). Animals were fed EPA and DHA from fish oil, or arachidonic acid - an omega-6 typically found in meats and dairy, and made in the body from other fats present in many vegetable oils. The investigators found that mice on the omega-3 diet initially lost 40-50% less retinal vessels compared to the omega-6 group. As a result, the omega-3 fed group had a 40-50% reduction in abnormal vessel growth.

One of the study's authors said: "If clinical trials find that supplementing with omega-3 s is as effective in protecting humans against retinal disease as demonstrated by the findings of this study, this cost effective intervention could benefit millions of people".

Better Colon Health?

Findings from a new study published in the American Journal of Epidemiology, add to a growing body of science linking omega-3 and fatty fish consumption to a reduced risk of colorectal cancer (2). Scottish researchers examined the type and amounts of fats in the diets of 1,455 subjects with colorectal cancer and the same number of matched healthy individuals.

Increased intake of EPA was associated with a 41% reduction in risk, while a 37% lower risk was linked to DHA intake, comparing highest against lowest average intakes. The omega-3s have been shown to reduce the body's inflammatory response (3). This is very important, because chronic inflammation is believed to be the culprit in about 20% of all cancers.

Healthier Prostates?

In addition to colorectal cancer, prostate cancer is also believed to be influenced by chronic inflammation. The incidence of prostate cancer has been increasing over the past 15 years, with over a half million new cases diagnosed every year worldwide.

Higher intake of the omega-3s DHA and EPA could cut the risk of developing this cancer by 40% according to a new study from Harvard (4). The investigators compared blood levels of fatty acids in 476 men with prostate cancer and the same number of healthy controls. The results tally with other studies reporting that regular intake of fatty fish like salmon is associated with a prostate-protective effect.

References

1. Connor KM, et al. Increased dietary intake of 3-poly-unstaturated acids reduces pathological retinal angiogenesis. Nature Medicine 13:868-874, 2007.
2. Theodoratou E, et al. Dietary fatty acids and colorectal cancer: a case-control study. American Journal of Epidemiology 166:181-195, 2007.
3. Wada M, et al. Enzymes and receptors of prostaglandin pathways with arachidonic acid-derived versus eicosapentaenoic acid-derived substrates and products. Journal of Biological Chemistry 282: 22254-66. 2007.
4. Chavarro JE, et al. A prospective study of polyunsaturated fatty acid levels in blood and prostate cancer risk. Cancer Epidemiology, Biomarkers and Prevention. 16:1364-70 ,2007.