Is It True That Omega-3 Fatty Acids Can Protect The Heart?

By Nadine Taylor, M.S., R.D.

Nadine Taylor is Chair of the Women's Council of the American Nutraceutical Association, and coauthor of Runaway Eating, Arthritis for Dummies and numerous other books. Her website is www.nadinetaylor.com.

This information is meant for educational purposes only. If you have or suspect you have any health problems, see your physician. Be sure to discuss any changes in your medications, supplements, diet and/or exercise habits with your physician.

Back in the 1970's, medical researchers began to get very interested in the Eskimos because they ate prodigious amounts of fat yet rarely suffered from cardiovascular disease. Back then, everybody believed that fat and CVD were inextricably linked, and we were in the throes of a "war on fat." Low fat was good, high fat was bad. What we didn't yet understand was that heart disease is less related to the amount of fat we eat than the kind of fat we eat. The kind of fat that the Eskimos were gobbling up wasn't the kind found in heavily-larded steaks, butter and lard. It came from fish, whales and seals and contained high amounts of omega-3 fatty acids. The researchers hypothesized that the reason the Eskimos didn't have much heart disease was because the omega-3 fatty acids were protecting their cardiovascular systems. Specifically, the omega-3s appeared to help lower their blood pressure and reduce their overall risk of suffering heart attacks.

A Little Background Information

Fat is not a single, uniform substance. Instead, it's composed of fatty acids, smaller substances which serve as the building blocks of fat. A fatty acid is a string of carbon atoms with hydrogen atoms attached. The fatty acids fall into two basic categories: saturated - which contain as many hydrogen atoms as they can possibly hold, and unsaturated - which do not. At room temperature most saturated fats are solid (butter or lard), while most unsaturated fats (oils) remain in liquid form. The omega-3s are unsaturated fats, only solidifying when cooled. It makes sense that fish, whales and seals living in cold arctic waters would have this form of fat on their bodies. If their body fat was composed of saturated fat it would solidify, and they would sink like stones!
Besides their ability to stay in liquid form even at low temperatures, the omega-3 fatty acids have been shown to lower blood pressure, inhibit the formation of blood clots, lower the levels of blood fat (triglycerides) and raise levels of the helpful HDL cholesterol. As a result, omega-3's can reduce the risk of heart attacks The best known of the omega-3 fatty acids are alpha linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

The Science Behind Using Omega-3s to Prevent Heart Attacks

A very impressive body of evidence supports the idea that the omega-3 fatty acids are heart healthy. For example:

- An article appearing in the Journal of the American Medical Association in 2002 reported on 85,000 women who were followed for 16 years. This study found that eating fish - a primary source of omega-3s - reduced the risk of developing heart disease (1) More specifically, this study found that consuming 2-4 fish meals per week lowered heart disease risk by 30%, while 5 fish meals per week cut the risk by 34%.
- In a report published in the American Journal of Clinical Nutrition, researchers studying a group of men for 17 years found that those with the highest blood levels of omega-3 fatty acids were 80% less likely to suffer a sudden fatal heart attack, compared to those with the lowest omega-3 levels. (2)

The Science Behind Omega-3s and Blood Pressure Reduction

High blood pressure (hypertension) is the third most deadly disease in the United States, afflicting more than 50 million Americans, or 1 out of every 4 adults, and killing over 40,000 of us per year. Yet a growing number of studies indicate that the omega-3 fatty acids can help keep blood pressure under control. For example:

- A study appearing in the New England Journal of Medicine reported that when 15 people with hypertension were given 15 grams of fish oil per day, their blood pressures dropped significantly. (3)
- Another report, published in the American Journal of Clinical Nutrition, reported positive results when 63 people with hypertension and hyperlipidemia (elevated cholesterol and elevated blood fats) were given omega-3 fatty acids. A dose of 3.65 grams per day, taken for about 4 months, significantly lowered the average blood pressure levels.
- The prestigious journal Circulation published a review of 31 individual studies looking at the effects of omega-3 fatty acids on elevated blood pressure.The review study found that fish oil significantly reduced blood pressure in those with mild hypertensionsion. And the larger the dose, the better the results. (4)

How Solid Is the Science?

The the idea that omega-3 fatty acids can help reduce cholesterol and blood pressure and thus protect the cardiovascular system is backed by a large number of population studies and clinical trials. A number of these studies/trials have been published in prestigious journals such as the Journal of the American Medical Association, the New England Journal of Medicine and the American Journal of Clinical Nutrition.

How Much to Take, What to Watch For

Many experts suggest taking 3-4 grams of omega-3 fatty acids per day as a means of protecting the cardiovascular system. You can get this amount by consuming:

- 1½ oz. of cold water fish daily; or
- three to five 3-ounce servings of cold water fish weekly; or
- 1-2 tsp. of fish oil daily; or
- 3-4 1000 mg. capsules of fish oil daily

The best sources of omega-3's are cold water fish such as anchovies, Atlantic sturgeon, herring, mackerel, salmon, sardines, tuna and trout. It's also found in supplements containing EPA, DHA and/or ALA.
While eating several servings of fish per week is felt to be helpful, there are a few things you should be aware of if you take omega 3's in their concentrated form as fish oil supplements:

- In some people fish oil may cause heartburn, nosebleeds, vitamin E depletion, belching and halitosis.
- Large doses may trigger loose stools and nausea.
- Using fish oil with medications or herbs that have anticoagulant or anti-platelet actions could increase the risk of bleeding.
- Fish oil may also interfere with certain anti-diabetic and anti-hypertensive drugs.
- Fish oil should be used with caution if you have diseases such as diabetes, hypertension or cirrhosis, or if you are aspirin sensitive.

I don't mean to alarm you; fish oil supplements are considered safe when taken in the proper amounts and under a physician's supervision. But because there are some potential interactions with diseases, you should work closely with your physician to coordinate your medications and supplements.

(1) Hu FB, et al. Fish and omega-3 fatty acid intake and risk of coronary heart disease in women. JAMA 2002;287(14):1815-21.
(2) Seidelin K, et al. N-3 fatty acids in adipose tissue and coronary artery disease are inversely related. Am J Clin Nut 1992;55:1117-1119.
(3) Knapp HR, FitzGerald GA. The antihypertensive effects of fish oil: a controlled study of polyunsaturated fatty acid supplements in essential hypertension N Engl J Med 1989;320:1037-1043.
(4) Morris MC, et al. Does fish oil lower blood pressure? A meta-analysis of controlled trials. Circulation 1993;88(2):522-33

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