Consumption of fish is associated with a decreased risk of heart disease. Early research focused on populations that had high fish consumption and low incidence of heart disease. Now clinical evidence of the protective effect of omega 3 fatty acids such as EPA and DHA is abundant. The primary omega 3 fatty acids from fish are EPA and DHA.

Omega 3 fatty acids reduce the risk of cardiovascular disease through several mechanisms. They can lower the levels of triglycerides through increased fatty acid oxidation (breakdown). They also lower the production of cholesterol in the liver (especially VLDL). Omega 3 fatty acids also decrease cardiovascular risk by lowering the levels of inflammation in the body by altering the arachadonic acid metabolism. Absorption of Omega 3 fatty acids into the tissue and cells of the body may provide further benefit.

A study published this year by the Journal of Thailand Medical Association documented the effects of fish oil consumption on serum indices of cardiovascular disease. There were 9 participants in the study that consumed 6 grams of fish oil daily for 48 weeks as well as received dietary advice. Participants were between the ages of 39 and 72 years of age with a positive history for high triglycerides.

The researchers measured the effects of fish oil on triglycerides, VLDL, LDL and serum and red blood cell levels of EPA and DHA at 0, 12, 24, 36 and 48 weeks. They found that levels of EPA and DHA in the serum and blood increased over the study period. Levels of VLDL and triglycerides decreased over the treatment period. Surprisingly LDL levels increased over the treatment period.

The results show that EPA and DHA are very highly bioavailability. They are easily absorbed and have few side effects. Fish oils exerted a positive protective effect by lowering the levels of triglycerides and VLDL, but the increase in LDL may be due to long term consumption of high levels of fish oil. The study has several limitations: small sample size, lack of control, and lack of a dose dependence relationship.