Wednesday, February 29, 2012

Flax and Heart Disease

The evidence that flax protects against heart disease is clear-cut. Experimental studies in laboratory animals and humans suggest that the omega-3 fatty acid alpha-linolenic acid (found in high amounts in flax) may reduce the risk of arrhythmia. Thus, researchers from the Department of Nutrition, Harvard School of Public Health, Boston, prospectively studied the association between dietary intake of alpha-linolenic acid and risk of fatal heart disease among 76,283 women without previously diagnosed heart disease.* During 10 years of follow-up, they documented 232 cases of fatal heart disease and 597 cases of nonfatal heart attacks. After adjusting for standard heart disease risk factors, a higher intake of alpha-linolenic acid was associated with a lower relative risk of fatal heart disease.

There was a 45 percent reduction of such incidences among women with the highest intakes of alpha-linolenic acid. For nonfatal heart attacks, there was a modest trend toward reduced risk. The researchers concluded, "A higher intake of alpha-linolenic acid is protective against fatal IHD [heart disease]. Higher consumption of foods such as oil-based salad dressing that provide polyunsaturated fats, including alpha-linolenic acid, may reduce the risk of fatal IHD [heart disease]."

Meanwhile, researchers from the Department of Human Biology and Nutritional Sciences, University of Guelph, Canada, performed a placebo-controlled, double-blind trial and found that omega-3 fatty acids can benefit women receiving and not receiving hormone replacement therapy. Use of omega-3 fatty does so by reducing the concentration of clot-forming blood lipids called triacylglycerols (i.e., triglycerides). In this study, women were given fish oil capsules providing 2.4 grams of eicosapentaenoic acid (EPA) plus 1.6 grams of docosahexaenoic acid (DHA) daily, or placebo.

Supplementation with the fish oil capsules was associated with 26 percent lower serum triglyceride concentrations and highly improved ratio of triglycerides to beneficial high-density lipoprotein (HDL) cholesterol. "These results show that supplementation with a fish-oil derived concentrate can favorably influence selected cardiovascular disease risk factors, particularly by achieving marked reductions in serum triacylglycerol concentrations and triacylglycerol:HDL cholesterol in postmenopausal women receiving and not receiving HRT," say the researchers. "This approach could potentially reduce the risk of coronary heart disease by 27% in postmenopausal women."