Omega-3 Research

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FOOD NEWS MARCH 2000

OMEGA-3 FATTY ACIDS

by Mary Ryzner, MS, RD Clinical Dietitian

A new appraisal of fat comes from studying its molecular building blocks - - fatty acids. Individual fatty acids can have very different effects on our health. Unfortunately, the typical Western diet is high in the types of fatty acids that are linked with some of our most serious health problems, while it is very deficient in some that are essential for optimal health - - namely, the omega-3 fatty acids. It has been estimated that the majority of the U.S. population is consuming 1/10 of the amount of omega-3 fatty acids required for normal functioning. Omega-3 fatty acids are building blocks of every living cell in the human body, and are absolutely essential for normal health and development. Without them, cells can't function, renew and maintain themselves properly. The body doesn't produce omega-3's. For good health, we need to supply them in our diet. Omega-3's promote cardiovascular health, increase memory, are crucial for learning ability, help brain and vision development of infants, help boost the immune system (i.e. against certain types of cancer), and promote natural joint flexibility and mobility (i.e. decrease rheumatoid arthritis).

The omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), play different, but equally vital, roles in the body. Researchers believe EPA helps reduce the stickiness of blood platelets, which helps prevent plaque build-up that can lead to heart attack and ischemic stroke, the most common type of stroke. EPA helps in the synthesis of hormone-like substances (prostaglandins) benefiting cardiac and joint health. DHA is the most highly- unsaturated fatty acid found in nature. 60% of the brain is made of fat, and 25% of that fat is DHA. DHA helps maintain normal mental function, memory and focus, and supports healthy structure for brain and eyes. DHA seems to help stabilize heart rhythm, decrease the chance of sudden cardiac death due to arrhythmia, and may help prevent irregular heartbeats in people recovering from heart attacks.

Strong scientific evidence suggests that proper intake of omega-3's helps reduce symptoms of depression, helps memory retention, and helps decrease the risk for dementia - - Alzheimer's Disease in particular. There are significantly lower rates of depression in countries with the highest omega-3 consumption (i.e. Japan), compared to those areas with the least omega-3 consumption (i.e. North America).

In regard to cardiovascular health specifically, omega-3's help strengthen our defenses against heart disease, stroke, and high blood pressure. Elevated triglycerides are now independently associated with the progression of atherosclerotic lesions, and triglyceride levels above 200 mg/dl are cause for serious concern. The omega-3's EPA and DHA have been shown to reduce the amount of triglycerides made and released into the blood stream. Omega-3's increase the activity of certain enzymes that help in the removal of triglycerides from the blood stream. Some studies have shown that omega- 3's increase HDL ("good") cholesterol, and reduce the build-up of white blood cells in atherosclerotic plaque. A new study published by the Wake Forest Bowman Gray School of Medicine showed that people with the recommended amount of omega-3's EPA and DHA in their diet had a 50% lower risk of death from heart disease and a 27% lower risk of death from all causes.

Omega-3 fatty acids have been shown to decrease the pain, swelling and stiffness of arthritis. This may be due to the effects on the immune response. Arthritis sufferers may have reduced need for medications when they have a sufficient intake of omega-3's.

Many people are deficient in the critical omega-3 fatty acids. According to a recent Multiple Risk Factor Intervention Trial study of intake of dietary fatty acids, 20% of the U.S. population has levels so low they defy detection. The average American diet contains less than 200 mg per day of the omega-3's EPA and DHA. Our hunter-gatherer ancestors consumed far more omega-3 fatty acids than we do today. The best scientific evidence suggests intake of omega-3's should be at least 650 mg per day. There is strong evidence that consuming considerably more than 650 mg per day provides even more health benefits. Some research shows 2,000 mg or more of fish oil daily can lower blood triglycerides, slow blood clotting and reduce blood pressure. Such high doses are difficult to get from food. Japan, England, and several European countries have set Recommended Daily Allowances for omega-3's, but none exist in the U.S. yet.

HA and EPA are abundant in ocean fish, with ideal intake being several 3-oz servings of fish per week. However, in North America, many of us don't eat much fish. Also, not all fish are rich in omega-3's, and even the ones that are can lose their omega- 3 potency when cooked improperly (i.e. deep fried). There is also research indicating that there is a lower risk of heart disease in people who eat any amount of fish, indicating that lower fat fish are also beneficial. It is very important to take precautions to avoid fish with potential high levels of toxins, and to pay attention to advisories not to eat fish from questionable waters. Farmed fish, such as rainbow trout and some salmon, is safer. Multiple vitamins and most herbal supplements don't contain any omega-3's. Special fish oil supplements are available, which will be discussed in Part 2 of this topic in the April issue.

How can vegetarians/non-fish eaters obtain omega-3's? Flaxseed, wheat germ, walnuts, tofu, canola oil, olive oil, spinach, mustard greens, and purslane contain alpha- linolenic acid - - another omega-3 fatty acid that can be converted to EPA and DHA in the body. However, these aren't nearly as efficient sources as is fish, and it's not clear if the converted alpha-linolenic acid acts exactly like fish oils do in the body.

For more information about good food sources of omega-3 fatty acids, and information on supplements, see the April 2000 Heart-to-Heart issue. Also, you can e- mail Mary Ryzner for more information and/or references on this topic at: run26@quixnet.net or voice mail at 888-287-7160.

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