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Fat has bad reputation—many people associate dietary fat with obesity, heart disease and other chronic conditions. But not all fat is bad fat. Some fats, known as omega-3 fatty acids, can lower the risk heart disease, improve brain function, fight arthritis and other inflammatory diseases, and enhance immune function.

In the late 1970s, Danish researchers compared the rates heart disease among Eskimos in Greenland to those among Danish populations. Despite their high-fat diet, the Eskimos were much less likely to suffer from heart disease than their Danish counterparts. How could this be?

Scientists hypothesized that the low levels of heart disease among Eskimos were related to their consumption of fish, whales and other marine mammals, all of which are high in omega-3 polyunsaturated fatty acids. Epidemiological studies of fish-eating populations in Japan and elsewhere supported this hypothesis, and subsequent research confirmed it. In 2000, researchers at the Mid America Heart Institute in Kansas City wrote that more than 4,500 studies confirmed the cardiovascular benefits of omega-3 fatty acids. The research on omega-3 fatty acids from marine sources may also apply to omega-3 fatty acids from flaxseed and other plant sources.


The human body can produce most of the fat it needs from carbon, hydrogen and oxygen. But the body can’t produce omega-3 and omega-6 fatty acids, although it needs both. Because these fats must be obtained from the diet, they are called essential fatty acids, or EFAs.

There are three types of omega-3 fatty acids: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA). The body can most readily use EPA and DHA, which are found primarily in fish and marine mammals. The body converts ALA, which comes from plant sources such as flaxseed, into DHA and EPA.

The other essential fatty acids—omega-6 fatty acids—are vital to our health, but most of us get too much of them in our diet. Most vegetable oils today are high in omega-6 fatty acids and low in omega-3 fatty acids, and the imbalance can cause health problems like heart disease, cancer and autoimmune diseases. For instance, a 2004 article in the New England Journal of Medicine linked cystic fibrosis to an imbalance of fatty acids.

In today’s diets, the ratio of omega-6 to omega-3 fatty acids is nearly 15 to one—far from the ideal one-to-one ratio of essential fatty acids that scientists believe our ancestors ate. However, we can probably improve our overall health even without achieving the ideal ratio. In 2002, Artemis Simopoulos, president of the Center for Genetics, Nutrition and Health in Washington, DC, reported that the EFA ratio needed to reduce health risks varies from condition to condition. For example, a four-to-one (omega-6 to omega-3) ratio may reduce the risk of dying from heart disease by 70 percent, but reducing the spread of colon cancer requires a 2.5-to-one ratio.


EFAs can help reduce the stickiness of blood platelets, reducing the risk of atherosclerosis (hardening of the arteries), stroke and heart attack. EFAs can also help lower levels of triglycerides and LDL cholesterol. EFAs have even been shown to have anti-inflammatory effects that can help fight illnesses such as arthritis, irritable bowel syndrome, asthma and more. In fact, EFAs in breast milk may reduce the risks of asthma and other atopic conditions in children.

Health Benifits of EFSs


Research shows that omega-3 fats can lower blood pressure, decrease LDL (“bad”) cholesterol levels, increase HDL (“good”) cholesterol levels and reduce the risk of heart attack, stroke and other vascular disorders. When heart attacks do happen, omega-3 fatty acids may make them less severe.

Omega-3s reduce the risk or severity of heart disease by influencing several factors, including blood clotting and blood pressure. There is also mounting evidence that omega-3s can protect the heart against arrhythmias (irregular heart rhythm), which can be fatal. According to the American Heart Association, arrhythmias are responsible for more than 780,000 hospitalizations per year.

In August 2003, an article in the European Journal of Medical Research reported that omega-3 fatty acid could reduce the risk of sudden cardiac death in as little as 90 days. The fatty acids were reported to be as effective as aspirin and statins in reducing the risk of sudden death from heart disease. The only treatment that proved more effective than omega-3 fatty acids was the use of beta-blockers, but even patients taking beta-blockers benefited from the addition of omega-3 fatty acids.

In 2004, the FDA recognized the health benefits of EFAs by approving a qualified health claim for products containing omega-3 fatty acids. Food and supplement companies can now state on the product label that EPA and DHA fatty acids may reduce the risk of coronary heart disease (CHD).

Also in 2004, a team of researchers wrote an article in Preventive Medicine proposing the “Omega-3 Index,” which they defined as the red blood cell composition of EPA and DHA. According to the authors, the Omega-3 Index is a reflection of long-term omega-3 intake and is a simple indicator of CHD risk.


Most studies on the antiarthritic effects of EFAs focus on the effects of omega-3 fatty acids on rheumatoid arthritis. Rheumatoid arthritis is an autoimmune disorder in which the immune system attacks the joints, causing pain and stiffness. In 1995, a meta-analysis in the Journal of Clinical Epidemiology revealed that taking fish oil supplements for at least three months resulted in modest but significant improvement in joint tenderness and morning stiffness. In 1996, a population-based study published in Epidemiology suggested that omega-3 fatty acids help prevent rheumatoid arthritis. The study’s authors reported that women who ate two or more servings of broiled or baked fish per week had about half the risk of developing rheumatoid arthritis as women who ate less than one serving per week.


Research indicates that omega-3 fatty acids may help prevent and treat certain cancers. A meta-analysis published in 2007 in the American Journal of Epidemiology reported that fish consumption could provide a slight reduction in colorectal cancer risk. The same year, researchers from the Oregon Health and Science University conducted a large-scale study on fatty acids and breast cancer in Shanghai, China. They found that omega-3 fatty acids provided a protective effect against breast cancer. Also in 2007, researchers from Wake Forest University in North Carolina investigated the effects of fatty acids on prostate cancer risk in genetically predisposed mice and found that omega-3 fatty acids reduced prostate tumor growth, while omega-6 fatty acids did the opposite.

There are other uses for omega-3 fatty acids. Researchers are looking into the links between fish oil and childhood asthma, healthier pregnancies (and healthier infants), improved bone growth, schizophrenia, Alzheimer’s disease and lengthened remission for patients in prolonged remission from Crohn’s disease. Some experts also believe that essential fatty acids can help lower the risk and severity of depression.


Fish—especially fatty fish—is an excellent source of EPA and DHA, and the American Heart Association recommends eating at least two serving weekly. However, some fish, especially larger, predatory species, may contain mercury, PCBs and other harmful toxins that can cause serious health problems.

Vegetarian sources of omega-3 fatty acids such as walnuts, soybeans and flaxseed are free of such toxins. These sources provide omega-3 fatty acids as ALA, which the body must convert in to EPA and DHA. The extent to which ALA is converted to EPA and DHA is still undetermined.

Supplements may be the best option for those who wish to ensure safe, optimal intake of omega-3 fatty acids. Fish oil supplements provide high levels of EPA and DHA and are generally free from mercury and PCBs. Krill oil, a newcomer to the supplement scene, is also an excellent choice. In addition to omega-3 fatty acids, krill oil contains astaxanthin, a potent antioxidant. Plus, krill oil is free of the fishy aftertaste associated with fish oil. For people who want vegetarian EFAs, flaxseed oil is a rich source of ALA.


Omega-3 fatty acids provide the body with vital building blocks that affect nearly every body system. From preventing cancer to battling arthritis to promoting heart health, these essential fats can do wonders for disease prevention and treatment. Fish oil and flaxseed oil are associated with a wide range of scientifically confirmed health benefits, making them some of today’s most valuable and popular dietary supplements.


Product names: Omega-3 fatty acids, EFAs (essential fatty acids), EPA (eicosapentaenoic acid), DHA (docosahexaenoic acid), ALA (alpha-linolenic acid)

Possible benefits: angina, arthritis, asthma, breast cancer, colon cancer, constipation, dermatitis, gout, heart disease, high blood pressure, high cholesterol, inflammatory conditions, irritable bowel syndrome, lupus, migraines, mood disorders, multiple sclerosis, osteoarthritis, rheumatoid arthritis, sciatica, stroke and suppressed immunity

Dietary Sources: fatty fish (albacore, bluefish, flaxseed, herring, mackerel, rainbow trout, salmon), walnuts, flaxseed, soy, canola

Supplement Sources: fish oil, flaxseed oil, krill oil

Possible Side Effects: Because of their blood-thinning capabilities, omega-3 fatty acids may increase bleeding time, and lead to more frequent nosebleeds and easy bruising. Do not take if you have a bleeding disorder or are on anticoagulants or are allergic to fish. Diabetics should consult with their physician before using EFAs. Flaxseed is generally regarded as safe.


Essential fatty acids, especially fish oil products, are sold under a variety of names. They may be called fish oil, omega-3 fats, EFAs, or they may be called by specific oil names such as DHA or EPA. Most fish oil products contain a mixture of DHA and EPA, no matter what they’re called. When in doubt, simply read the ingredient label.

Flaxseed products are available in liquid and gelatin capsules. Flaxseed oil is sometimes sold by itself, and sometimes mixed with other omega-3 fatty acids. Again, when in doubt, check the label.


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Berquin, I.M. et al. 2007. “Modulation of prostate cancer genetic risk by omega-3 and omega-6 fatty acids.” Journal of Clinical Investigation 117(7): 1866–75.

Fortin, P.R. et al. 1995. “Validation of a meta-analysis: the effects of fish oil in rheumatoid arthritis.” Journal of Clinical Epidemiology 48(11): 1379­–90.

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Shapiro, J.A. et al. 1996. “Diet and rheumatoid arthritis in women: a possible protective effect of fish consumption.” Epidemiology 7(3): 256–63.

Simopoulos, A.P. 2002. “The importance of the ratio of omega-6/omega-3 essential fatty acids.” Biomedicine & Pharmacotherapy 56(8): 365–79.