Dietary sources of omega-3 fatty acids include fish oil and certain plant/nut oils. Fish oil contains both docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), while some nuts (e.g., English walnuts) and vegetable oils (e.g., canola, soybean, flaxseed/linseed, and olive oil) contain alpha-linolenic acid (ALA). Evidence from several studies has suggested that amounts of DHA and EPA in the form of fish or fish oil supplements lowers triglycerides, slows the buildup of atherosclerotic plaques ("hardening of the arteries"), lowers blood pressure slightly, as well as reduces the risk of death, heart attack, dangerous abnormal heart rhythms, and strokes in people with known heart disease. However, high doses may have harmful effects, such as an increased risk of bleeding. Although similar benefits are proposed for alpha-linolenic acid, scientific evidence is less compelling, and beneficial effects may be less pronounced. Some species of fish carry a higher risk of environmental contamination, such as with methylmercury.
DHEA (dehydroepiandrosterone) is an endogenous hormone (made in the human body) secreted by the adrenal gland. DHEA serves as precursor to male and female sex hormones (androgens and estrogens). DHEA levels in the body begin to decrease after age 30, and are reported to be low in some people with anorexia, end-stage kidney disease, type 2 diabetes (non-insulin dependent diabetes), AIDS, adrenal insufficiency, and in the critically ill. DHEA levels may also be depleted by a number of drugs, including insulin, corticosteroids, opiates, and danazol. There is sufficient evidence supporting the use of DHEA in the treatment of adrenal insufficiency, depression, induction of labor, and systemic lupus erythematosus. There is a lack of available studies on the long-term effects of DHEA. However, DHEA may cause higher than normal levels of androgens and estrogens in the body, and theoretically may increase the risk of prostate, breast, ovarian, and other hormone-sensitive cancers. Therefore, it is not recommended for regular use without supervision by a licensed healthcare professional.