Medscape Medical News  Omega-3 Fatty Acids Improve Systemic Arterial Compliance Laurie Barclay, MD Medscape Medical News 2002. © 2002 Medscape July 26, 2002 — Two omega-3 fatty acids contained in fish, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), significantly improve systemic arterial compliance, according to the results of a double-blind, placebo-controlled trial reported in the August issue of the American Journal of Clinical Nutrition. As a result, systolic and pulse pressure and total vascular resistance tended to decrease, while triglyceride levels dropped significantly. "Substantial epidemiologic and other evidence shows that eating fish may benefit people at high risk for ischemic heart disease (IHD), [and] sudden cardiac deaths occur less frequently in individuals who habitually [eat] fish," write Paul Nestel, from Baker Medical Research Institute in Melbourne, Australia, and colleagues. "Because of increasing evidence linking heightened pulse pressure, a reflection of increased arterial stiffness, to increased coronary risk, interventions that improve arterial compliance are thought likely to reduce risk for IHD." During a seven-week dietary intervention, 38 middle-aged men and women with elevated plasma total cholesterol were randomized to treatment with an EPA supplement (3 g/day), a DHA supplement (3 g/day), or placebo. Systemic arterial compliance was unchanged in the placebo group, rose 36% in the EPA group and 27% in the DHA group (P=.043), and there was a trend toward reduced systolic and pulse pressure in the omega-3 fatty acid groups. Plasma total and very low density lipoprotein triacylglycerol concentrations were significantly lower in the treatment groups than in the placebo group (P=.026 and .006, respectively). "EPA and DHA increase systemic arterial compliance and tend to reduce pulse pressure and total vascular resistance, effects that may reduce the risk of adverse cardiovascular events," the authors write. Am J Clin Nutr. 2002;76:326-330 Reviewed by Gary D. Vogin, MD Laurie Barclay, MD, is a staff writer with WebMD. Medscape Medical News is edited by Deborah Flapan, an associate editor at Medscape. Please send press releases and comments to news@webmd.net.

Fish Oil Reduces Body Fat Mass Obesity is not only widespread in world populations, but has been designated by the World Health Organization as an important risk factor for heart disease, diabetes, certain cancers and a number of other disorders. As a result, many scientists are currently focusing on ways to combat this growing problem. New research, as reported in the March 1998 issue of PUFA Newsletter, suggests that omega-3 fatty acid supplementation may reduce body fat mass. Data from animal studies has indicated that omega-3 fatty acids, which are found in fish and fish oil, may modulate the balance between the proportion of fat that is burned up as energy and the amount that is stored. For example, feeding rodents fish oil reduces weight gain and the deposit of body fat. In a recent study at Bretonneau Hospital, Tours, in France, a group of six healthy volunteers (five men and one woman) were given tests with two types of diet. First, they spent three weeks on a conventional French diet, with no restrictions on quantity, eating meals prepared by a dietitian and comprising 52 per cent carbohydrates, 16 per cent protein and 32 per cent fat. Then, between 10 and 12 weeks later, the volunteers ate the same diet for a further three weeks except that 6 g of fat (such as butter, olive oil and sunflower oil) was replaced by 6 g of fish oil each day. The latter was administered as capsules containing 1.8 g per day of fish oil, which, depending on the species, is equivalent to between 100 and 200 g of fish. At various times the researchers measured energy intake, physical activity, weight, metabolic rate, and other indicators including body composition. Substituting fish oil for the same amount of visible fat appeared to stimulate the resting metabolic rate by some four per cent, reports Dr C. Couet, who led the investigation. Over the three weeks, subjects eating the control diet showed a 0.30 kg reduction in body fat. However, while eating the fish oil diet the decrease in body fat almost tripled to 0.88 kg, even though there was no change in weight. The absence of weight loss may have been due to the very short period of the tests. The number of participants in the study was too small to draw conclusions about the usefulness of fish oil supplements in management of obesity, the investigators noted. However, further research with larger numbers and including obese patients is now envisaged.