Omega-3 fatty acids

Omega-3 fatty acids are one of two groups of fatty acids—the omega-3s and the omega-6s—that are vital to human life. They are called essential fatty acids (EFAs), which the body cannot make but absolutely needs for normal growth and development.

These fats must be supplied by diet. People living in industrialized western countries eat up to 30 times more omega-6 than omega-3 fatty acids, resulting in a relative deficiency of omega-3 fats.

Omega-6 metabolic products (inflammatory prostaglandins, thromboxanes, and leukotrienes) are formed in excessive amounts causing allergic and inflammatory disorders and making the body more prone to heart attacks, strokes, and cancer.

Eating diets rich in omega-3 acids or taking fish oil supplements can restore the balance between the two fatty acids and can possibly reverse these disease processes.

General use

Heart disease and stroke

The American Heart Association (AHA) has endorsed omega-3 fatty acids as good for the heart. The omega-3 oils increase the concentrations of good cholesterol (high density lipoproteins, HDL) while decreasing the concentrations of bad cholesterol (triglycerides).

In addition, eating omega-3-rich food will result in a moderate decrease in total cholesterol level. In a clinical study of 38 women, flaxseed flour, which contains high amounts of omega-3 fatty acids, decreased total cholesterol level by 6.9% and LDL cholesterol by 14.7%.

In addition, lipoprotein(a), which is associated with heart attacks in older women, decreased by almost 10%. Thus, omega-3 fatty acids are natural alternatives to estrogen in prevention of heart attacks in postmenopausal women.

Furthermore, omega-3 oils protect the heart by preventing blood clots or keeping other fats from injuring the arterial walls. They not only relax arteries but also help to decrease constriction of arteries and thickening of blood.

Hundreds of studies have shown that diets rich in omega-3 fatty acids decrease risk of heart attacks, strokes, and abnormal heart rhythms.

Eskimos, who eat a lot of cold-water fish, have low rates of heart attacks and strokes, possibly because they have thinner blood, high HDL to LDL cholesterol ratio, and less buildup of fatty deposits (plaques) in the arteries. Two clinical trials have shown that regular consumption of fish or fish-oil supplements can prevent sudden deaths due to abnormal heart rhythms.

In the Diet and Reinfarction Trial (DART) of 2,033 men who previously suffered a heart attack, men who ate two to three servings of fatty fish a week had their risk of sudden cardiac death lowered by 29% compared to those who had a low fat or high fiber diet.

In the Physician’s Health Study of 20,551 doctors, a 52% reduction in risk of heart attacks was observed in those who ate at least one fish meal per week compared with those who ate fish once a month or less.

Mild hypertension

Several studies have shown that eating 200 g of fatty fish or taking six to 10 capsules of fish oil daily will lower blood pressure (BP). Therefore, omega-3 can benefit patients with borderline high blood pressure. Omega-3 oils also effectively prevent hypertension in cardiac patients after transplantation.

Supplement for newborns and babies

Omega-3 fatty acids are essential for normal development of vision and brain function, especially in newborns and children. Very low birth weight pre-term infants often have poor vision and motor skills, possibly because they receive less than one-third of the amount of omega-3 fatty acids outside the mother’s womb that they would have received as a fetus.

Human breast milk contains the appropriate amount of omega-3 and -6 fats and is believed best for babies. If mother’s milk is unavailable, formulas with soybean oil that provide higher amounts of omega-3 fatty acids are more beneficial than those made from cow milk.

Even full-term babies benefit from the addition of essential fatty acids to cow-milk formulas. Studies have shown that babies given formulas supplemented with EFAs have better vision and score higher in skills and problem-solving tests compared to babies on formulas that do not contain additional EFAs.

Rheumatoid arthritis

Because omega-3 fatty acids inhibit the action of inflammatory prostaglandins and leukotrienes, they can help control arthritis symptoms. Significant reduction in the number of tender joints and morning stiffness, as well as an increase in grip strength, have been observed in patients taking fish oil capsules.

Studies have shown that patients taking fish oil supplements for rheumatoid arthritis require fewer pain medications; some are able to discontinue their nonsteroidal anti-inflammatory treatment.

Despite the beneficial effects of omega-3 fats, regular antirheumatic drugs and nonsteroidal anti-inflammatory medications most likely still are required to control this chronic condition.


Early studies in laboratories indicate that omega-3 fatty acids in fish oils might prolong life in people with autoimmune disorders like diabetes. A new study looked at substituting fish oil for corn oil in diets and found a tendency to suppress immune system dysfunction and prolong life. More studies are required to prove the diet’s benefits in humans.

Inflammatory bowel disease

High-dose fish-oil supplements have shown to decrease abdominal cramping, diarrhea, and pain associated with Crohn’s disease. In one study of 96 patients, patients who received 4.5 g of omega-3 fatty acids (15 fish oil capsules) required significantly less steroids to control symptoms.

In another study of 78 Crohn’s disease patients, 59% of patients who received nine fish oil capsules (2.7g of omega-3 fatty acids) daily did not have any disease flare-ups for at least one year compared to 26% recurrence rate in patients who were not given fish oil. Omega-3 fatty acids also are effective in preventing reappearance of Crohn’s disease after surgery to remove sections of diseased bowel.

In a clinical trial involving 50 patients, patients who received 2.7 grams of omega-3 fats as fish oil cut their rate of disease reappearance in half compared to patients receiving placebo. However, the effectiveness of omega-3 oils varies depending on the type of omega-3 oils being used, length of use, and the patient’s diet.


Taking high dose omega-3 fatty acids can reduce inflammation of the airways and reduce asthma attacks. According to Donald Rudin, the author of the book titled Omega-3 Oils, allergic disorders such as asthma may be triggered by too much omega-6 and too little omega-3 fats in our body.

Excessive amounts of omega-6 prostaglandins cause the body to produce antibodies that cause allergic reactions. Flaxseed or fish oil supplements can keep the omega-6 fats in check and decrease the inflammatory reactions associated with asthma.

Berger’s disease (Immunoglobulin A nephropathy)

Omega-3 fats may be effective in treating this autoimmune disease in which kidney function fails over time with few treatment options available.

In a large, randomized study of 150 patients, those who received 3 g of omega-3 fatty acids daily for two years had significantly less reduction in renal function than those treated with placebo. Therefore, omega-3 fatty acids appear to have protective effects and may stabilize renal function in these patients.

Raynaud’s disease

There have been few studies evaluating the effects of omega-3 fatty acids in treating Raynaud’s disease; however, it appears that fish oil supplements may alleviate some blood clotting disorders.

Mental disorders

According to some studies, many common mental disorders, such as depression, bipolar disorder (manic-depression), attention-deficit hyperactive disorder (ADHD), anxiety, or schizophrenia, may be triggered by deficiencies of omega-3 fatty acids and/or B vitamins.

The rates of depression are low in countries that eat a lot of fish, while the rate of depression steadily rises in the United States as Americans eat increasingly more processed food and less fresh fish and vegetables containing omega-3 fats.

In one study, 53% of bipolar patients on placebo (olive oil) became ill again within four months, while none of the patients who were given 9.6 g daily of omega-3 fatty acids (as fish oil) did.

Supplements containing omega-3 fats also reportedly have been effective in children with ADHD precipitated by essential fatty acid deficiencies. Furthermore, a 25% decrease in schizophrenic symptoms was observed in patients receiving eicosapentanoic acid (EPA), one of the omega-3 fatty acids contained in fish oil.

A report in 2001 revealed that omega-3 fatty acids may have effects on stabilizing mood and relieving depression. As studies continue, researchers are finding it more and more evident that omega-3 fatty acids can be effective for treating depression, though they still are uncertain exactly how they work. A 2003 report linked depression to increased risk of sudden cardiac death.

Acquired Immunodeficiency syndrome (AIDS)

In a small study of 20 AIDS patients, those who received fish oil supplement at dosage of 10 g of omega-3 fatty acids per day for 30 days gained more weight (2.4 kg) and significantly lowered their concentrations of tumor necrosis factor, which is believed to cause wasting in AIDS patients, compared to those who did not.

Cancer prevention

Omega-3 fatty acids inhibit tumor growth when injected into animals. Flaxseed oil, which is a plant source of omega-3 fatty acids, has been shown to prevent cancer of the breast, colon and prostate.

The Mediterranean diet, which is heart healthy, also can decrease risk of getting cancer. Omega-3 fats, it seems, strengthen the immune systems and inhibit the inflammation and blood circulation of the tumors.


Omega-3 fatty acids can be found naturally in the oil of cold-water fish, such as mackerel, salmon, sardines, anchovies, and tuna, or as extracted oils from plants, such as flaxseed, canola (rapeseed), or soybean.

As of 2001, the U.S. Food and Nutrition Board had not issued the recommended daily allowance (RDA) for omega-3 fatty acids. However, researchers suggest that 100-200 mg daily of docosahexaenoic acid (DHA) and 200-400 mg daily of eicosapentanoic acid (EPA) were adequate for the majority of adults.

The best way to achieve this dietary requirement is by eating fatty fish two or three times a week and/or eating vegetables and oils containing omega-3 fatty acids. If fish oil supplement is preferred, then one to two capsules a day is sufficient.

Each 1 g fish oil capsule normally contains 180 mg of EPA and 120 mg of DHA. Vitamin E is often contained in fish oil supplements to prevent spoilage and vitamin-E deficiency, which may occur with high dose fish-oil consumption.

Patients should take supplements containing omega-3 fatty acids only under professional supervision to prevent overdosage, adverse reactions, or interactions with other medications. For treatment of diseases, flaxseed oil should be the first choice because it is the richest source of omega-3 fatty acids, relatively safe, and inexpensive.


The safest and most effective way to get omega-3 fatty acids is through diets of at least three fish meals a week. Fish-oil or flaxseed supplements should be taken only under a physician’s supervision.

Although fish oils can be helpful in relieving arthritic symptoms, patients still may need anti-inflammatory medications to adequately control the disease.

Taking any medication during pregnancy is not recommended. Women who are pregnant or breastfeeding should talk to doctors before taking fish-oil supplements or any other medications.

Because of its blood thinning activity, those who are on aspirins, nonsteroidal anti-inflammatory drugs (NSAIDS), warfarin, or other anti-clotting medications must consult a physician before using the supplements.

Side effects

Consuming excessive amounts of fish-oil capsules can result in excessive bleeding, gastrointestinal distress, anemia, or strokes.


Because of its blood-thinning activity, fish oil supplements may interact with aspirins, nonsteroidal anti-inflammatory drugs (NSAIDS), warfarin, or other anticlotting medications to cause excessive bleeding.