Take it to Heart By now, you and most e-Alert readers could probably recite this key dietary maxim in your sleep: For optimum heart health, the ideal ratio of omega-3 fatty acid intake to omega-6 intake should be 1:1. Now a new study demonstrates exactly why this maxim is critical to a large segment of the population that has a genetic inclination to develop atherosclerosis. Most strokes and heart attacks are triggered by atherosclerosis; the gradual increase of cholesterol on the interior walls of arteries. And while the risk for atherosclerosis is known to run in families, the specific genetic markers have eluded researchers. This new study - a combined effort from the University of Southern California and the University of California at Los Angeles - sprang from animal research at UCLA, which indicated that a variation of a gene called 5-lipoxygenase (ALOX5; associated with inflammation) might be linked to atherosclerosis risk. The California team used data collected from the Los Angeles Atherosclerosis Study, an ongoing research project that follows the cardiovascular health records of nearly 500 Southern California utility workers. Three factors were examined: 1) dietary details over a period of 18 months, 2) thickness of the carotid artery walls (measured with ultrasound on each subject), and 3) presence of the ALOX5 gene variation (discovered in six percent of the subjects). The researchers found that among those with the ALOX5 variation, the buildup of arterial plaque was about 18 percent more advanced than among those with the common type of the gene. Furthermore, the dietary records revealed that an intake of omega-6 fatty acids "significantly enhanced" the formation of plaque among those with the gene variation, while a greater intake of omega-3 fatty acids "blunted the effect." More research is needed to establish the importance of the ALOX5 variation in predicting atherosclerosis. Nevertheless, this could be a breakthrough in heart disease research. Study co-author Hooman Allayee, Ph.D., told Science Daily that their conclusions suggest that ALOX5 could be used as a genetic marker for heart disease, "and should lead to improved diagnosis, prevention and treatment for atherosclerosis." Previous studies have shown that diets rich in omega-3 fatty acids may also lower triglyceride levels, reduce platelet aggregation or clumping, and improve the functioning of cells that line the heart and blood vessels. In the e-Alert "Fish in Fashion" (4/10/02), I told you about a study that examined the effects of omega-3 fatty acids on women's heart health. Analyzing 16 years of data, collected from more than 120,000 women in the Nurses' Health Study, researchers found that women in the group with the highest omega-3 intake had about half the risk of developing coronary heart disease compared to women in the group with the lowest intake. Overall, the relative risks of developing heart disease, dying from a cardiac event, or suffering a non-fatal heart attack all decreased steadily as fish consumption and omega-3 fatty acid intake increased. In another study, published in the journal Circulation, researchers tested the effects of fish oil and vitamin E on people who had suffered a heart attack in the three months previous to the test period. More than 11,000 men and women were randomly divided into four groups: one group received one gram of fish oil each day, one received 300 mg of vitamin E each day, the third group took both fish oil and vitamin E, and the fourth took a placebo. The participants in all four groups were particularly vulnerable to sudden cardiac death because of their recent heart attacks. But after just four months, the fish oil group already demonstrated a significant reduction in risk. In fact, participants who took fish oil had about half the incidence of sudden death compared to participants in the other groups. Longtime e-Alert readers know that the easiest way to increase consumption of omega-3 fatty acids is by increasing your fish intake; dark meat fish like mackerel, salmon, sardines, bluefish, and swordfish contain the most concentrated sources, with an average of 1.51 grams of omega-3s per serving. Most other fish, including canned tuna, provide about .45 grams per serving, while shrimp, lobster and scallops contain about .32 grams per serving. But as the Circulation study shows, fish oil supplements also provide an effective source of omega-3. And with the disturbing reports we're hearing more often these days about mercury levels in fish, supplementing with fish oil might be the safest way to go. Here in Baltimore, a local television station recently purchased ten samples of fresh swordfish and tuna steaks from several stores in the area, and sent the samples to a certified lab for testing. Nine out of the ten samples had mercury levels higher than the FDA's recommended safe standard, and four of the samples had mercury levels that were more than twice as high as the standard. (And that's assuming that you feel comfortable with the FDA's standard!) Unfortunately, some fish oil supplements can also contain traces of mercury and other pollutants. To insure the highest quality of fish oil, look for pharmaceutical grade fish oil that's been molecularly distilled. The molecular distillation process effectively separates toxic heavy metals from the oil. Also note that you probably don't need mega-doses of fish oil. The one-gram per day used in the Circulation study is a relatively low dose. Nevertheless, with just a few months of use it provided protection to a highly vulnerable population. To Your Good Health, Jenny Thompson
Health Sciences Institute Sources:
"Arachidonate 5-Lipoxygenase Promoter Genotype, Dietary Arachidonic Acid, and Atherosclerosis" New England Journal of Medicine, Vol. 350, No. 1, 1/1/04, content.nejm.org
"First Link Found In Humans Between Common Gene And Artery-clogging Disease" Science Daily, 1/1/04, sciencedaily.com
"Fish Oil Blocks Artery-Clogging Gene" Dr. Joseph Mercola, 1/14/04, mercola.com
"Fish and Omega-3 Fatty Acid Intake and Risk of Coronary Heart Disease in Women" Journal of the American Medical Association, Vol. 287, No. 14, April 2002, jama.ama-assn.org
"Early Protection Against Sudden Death by n-3 Polyunsaturated Fatty Acids After Myocardial Infarction" Circulation, Vol. 105, No. 16, 4/23/02, circ.ahajournals.org
"High Mercury Levels Found in Some Supermarket Fish" WBAL Television, 2/6/04, thewbalchannel.com
|
