International Omega-3 Learning and Education Consortium for Health and Medicine

Growth and development

Omega-3 fatty acids are structural components of cells of the central nervous system and therefore are essential nutrients for brain development. Docosahexaenoic acid (DHA) is the principle omega-3 fatty acid essential for brain and neural development and for retinal development of the eye for proper vision development in the infant.

Coronary heart disease (CHD)

Accumulating evidence indicates that long chain omega-3 fatty acids found in fish, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), decrease the risk of CHD and ischemic heart disease. Large epidemiological studies, such as the Physicians' Health Study and the Nurses' Health Study, examined dietary and other lifestyle factors that influence health outcomes. The Physician's Health Study reported that consumption of one or more servings of fish per week was associated with a 52% lower risk of sudden cardiac disease compared to less than one fish meal per week. In another epidemiological study, the Nurses Health Study in America, it was found that consumption of five or more servings of fish per week was associated with 45% fewer cardiac deaths compared to consumption of one fish meal per month. Long chain omega-3 fatty acids are known to be a protective dietary factor for cardiovascular disease. EPA and DHA have been shown to lower triglyceride levels and act as anti-arrhythmic agents. The American Heart Association (AHA) performed comprehensive reviews of the data for fish and fish oil consumption and cardiovascular disease. The AHA report recommends that individuals with and without heart disease and elevated blood triglyceride levels consume fish or take a fish oil supplement. A report prepared in 2003 by The Third Task Force of European and Other Societies also recommends fish oil as a standard therapy for post-myocardial infarction management.

High blood triglycerides

The level of triglycerides in blood is positively associated with an increase in CHD, as triglyceride levels increase so does the risk of CHD. Multiple factors influence the elevation of serum triglycerides throughout life with a major contributor being the diet. Both DHA and EPA, which are abundant in many marine seafood products, appear to support cardiovascular health and lower blood triglyceride levels. It is known that fish oil can reduce serum triglyceride levels by 20-50%, similar to the effects observed with medications such as statins, niacin and fibrates. The American Heart Association (American Heart Association fish and omega-3 fatty acids) recommends that individuals without documented CHD consume two servings of fish (preferably fatty fish, please see Food products) per week. Patients with CHD should consume 1 gram of EPA and DHA per day preferably from fatty fish or in a supplemental form (if under the care of a physician). For those patients who need to lower triglyceride levels, the American Heart Association recommends 2-4 grams of EPA and DHA per day in supplemental form under a physician's care. A prescription form of EPA and DHA, Lovaza (formerly known as Omacor), is a good omega-3 fatty acid source available for people with high levels of blood triglycerides. Each Lovaza 1 gram capsule contains 465 mg EPA ethyl ester, 375 mg DHA ethyl ester, 80 mg of other omega-3 fatty acids, 30 mg of omega-6 fatty acids and 50 mg of antioxidants. It is prescribed as an adjunct to diet to reduce very high triglyceride levels in adult patients.

Chronic disease

In medical research, omega-3 fatty acids are being investigated to determine whether they can effectively improve a wide range of disease states-among them, heart disease, diabetes, inflammation, depression, Alzheimer's and attention deficit disorder - making this group of nutrients an exciting and very active area of clinical research. Ensuring that omega-3 fatty acids are a part of the diet as recommended by dietary guidelines is a proper starting point to achieving better health; hence, a great opportunity exists in the potential for improving the human condition with omega-3 fatty acids.

Below is a short list of some hot topics in omega-3 fatty acid research. Please visit the Library and the NIH PubMed Central Survey to learn more about peer reviewed publications on omega-3 fatty acids and chronic disease.

• Epidemiological studies on the long-chain omega-3 fatty acids, DHA and EPA, suggest an inverse relationship of dietary intake with cognitive impairment and decline or dementia like Alzheimer's disease; such that, those with greater dietary intakes of EPA and DHA had less cognitive impairment, decline or dementia. Emerging evidence suggests that DHA may reduce dementia in aging adults supporting a role for omega-3 fatty acids throughout the life cycle. Supplementation of the diet with DHA and EPA was reported to improve mental health in schizophrenic subjects and may improve cognitive function in the elderly with dementia.
• Epidemiological studies reveal that populations consuming omega-3 fatty acids may experience a lower incidence of cancers and may improve disease conditions associated with chronic inflammation. The omega-3 fatty acids, DHA and EPA, can reduce tissue levels of the omega-6 fatty acid arachidonic acid, which is the precursor for prostaglandin E₂ production, a potent pro-inflammatory compound in the body. In this case, certain omega-3 fatty acids may help control inflammatory processes that contribute to disease.
• American Heart Association guidelines and recent studies indicate hemodialysis patients have high cardiovascular risk, consume inadequate amounts of dietary omega-3 fatty acids, and have suboptimal blood levels of omega-3 fatty acids. Supplementation of hemodialysis patients with dietary sources of EPA and DHA resulted in an increase of omega-3 fatty acids in blood (see also Benefits of omega-3 fatty acids in kidney disease patients).