Omega-3 Fatty Acids

Omega 3 fatty acids are essential (unsaturated) fatty acids, which means that the body cannot produce them but they are, nonetheless, necessary for normal metabolic functioning.  Perhaps the three best known are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

Food Sources of ALA, EPA, and DHA

ALA is found in vegetable oils (including olive, linseed/flaxseed, canola, and soybean) and certain nuts (such as walnuts).  DHA and EPA are in fatty fish and fish oil including lake trout, salmon, anchovies, herring, catfish, striped sea bass, whitefish, albacore tuna, halibut, pompano, bluefish, and mackerel.

Research About ALA, EPA, DHA, and Other Omega-3 Fatty Acids


Small decreases in blood pressure have been observed with regular consumption of omega-3s; some evidence suggests that DHA may be more beneficial than EPA in aiding this.  Not that high doses are unnecessary for achieving this benefit and may even raise risks associated with bleeding. 

High triglycerides

The combination of DHA and EPA (usually from fish oil supplements or eating fish) has been consistently shown to substantially lower triglyceride levels in the blood.  However, this has been accompanied by higher levels of LDLs (“bad” cholesterol).

Preventing second heart attacks

When people who have had a heart attack added fish oil supplements or specific oily fish to their diets, studies showed a decrease in sudden death, both fatal and non-fatal heart attacks, and mortality from any cause.  It should be noted that most of the participants were also taking standard medications for heart problems so these oils may simply enhance the effects of other treatments.

Cardiovascular Disease

Epidemiological studies have provided conflicting reports of decreased morbidity from heart disease in certain populations that habitually consume seafood.  Although it seems clear that fish oil provides some benefit in this area, more research is necessary.

Rheumatoid Arthritis

Fish oil in particular has been demonstrated to relieve such symptoms as joint tenderness and morning stiffness in patients with rheumatoid arthritis, particularly when used in combination with NSAIDS (i.e., anti-inflammatory medicines such as aspirin or ibuprofen).  However, studies have not reported results beyond 3 months and stronger designs would help to verify earlier results.

Although research is being conducted on the role of omega-3 fatty acids in the prevention or treatment of the following conditions, no conclusions can be drawn at this time:  angina pectoris, asthma, atherosclerosis, psoriasis, preeclampsia bipolar disorder, nephrotic syndrome, cancer, arrhythmias, schizophrenia, colon cancer, Crohn’s disease, cystic fibrosis, dementia, stroke, depression, dysmenorrhea, eczema, ulcerative colitis, IgA nephropathy, and eye and brain development in infants.

How Much Omega-3 Fatty Acid Should I Ingest?

According to the American Heart Association, healthy adults should eat fish at minimum twice weekly.  The WHO (World Health Organization) and some country-specific health agencies advise getting about 0.8 to 1.1 grams of ALA per day and 0.3 to 0.5 grams of DHA and EPA.  Importantly, however most Americans consume nearly ten times the amount of omega-6 fatty acids than they do omega-3s; these fatty acids are in competition for conversion into metabolites.  Therefore, in addition to getting sufficient omega-3s in one’s diet, balancing intake of omega-3s and omega-6s is a helpful goal.