Mercury, fish oil, and risk of heart disease. (Scientific update: a review of recent scientific papers related to vegetarianism).Is it necessary to eat fish to reduce risk of heart disease? Although some groups have recommended this, recent studies raise concern about the mercury levels in fish. Fish, especially fatty fish and fish oil, are significant dietary sources of mercury, which may predispose pre·dis·pose v. To make susceptible, as to a disease. people to heart disease. Two studies examined whether the mercury content of fish counteracts the beneficial effects that the omega-3 fatty acids This is a list of omega-3 fatty acids. Common name Lipid name Chemical name α-Linolenic acid (ALA) 18:3 (n-3) octadeca-9,12,15-trienoic acid Stearidonic acid 18:4 (n-3) octadeca-6,9,12,15-tetraenoic acid found in fish have on the heart. The first study (Guallar) examined close to 700 men throughout Europe and Israel who had had a heart attack. They were compared to almost 700 men who had not had a heart attack. The toenail toenail /toe·nail/ (to´nal) the nail on any of the digits of the foot. ingrown toenail see under nail. toe·nail n. mercury level in men who had a heart attack was 15% higher than in those who had not. The level of mercury in the men was related to blood levels of DHA DHA docosahexaenoic acid. DHA, n.pr See acid, docosahexaenoic. , a fatty acid fatty acid, any of the organic carboxylic acids present in fats and oils as esters of glycerol. Molecular weights of fatty acids vary over a wide range. The carbon skeleton of any fatty acid is unbranched. Some fatty acids are saturated, i.e. found mainly in fish. This suggests that high levels of mercury were due to higher fish consumption. A beneficial effect of higher blood levels of DHA was not seen unless mercury levels were controlled for. This suggests that the high mercury content of some fish may markedly reduce any beneficial effects of fish oil on risk of heart disease. The second study (Yoshzawa) was smaller but may have had similar results if only a large number of dentists had not been included. Dentists would be expected to have higher levels of mercury due to their exposure to mercury in their practice. However, this form of mercury is different from the methylmercury found in fish and may have a different effect on the risk of heart disease. These studies suggest that there should be some rethinking of recommendations to eat fish for your heart. (For more information about recommendations related to fish consumption, see Vegetarian Journal Sept/Oct 2001, American Heart Association American Heart Association (AHA), n.pr a national voluntary health agency that has the goal of increasing public and medical awareness of cardiovascular diseases and stroke, and thereby reducing the number of associated deaths and disabilities. Calls for Eating Fish Twice Per Week--What's a Vegetarian To Do? This article is on the web at <www. vrg.org/journal/vj2001sep/2001sepomega3.htm>.) Guallar E, Sanz-Gallardo I, Van't Veer P, et al. 2002. Mercury, fish oils, and the risk of myocardial infarction. N Engl J Med 347:1747-54. Yoshzawa K, Rimm EB, Morris JS, et al. 2002. Mercury and the risk of coronary heart disease coronary heart disease: see coronary artery disease. coronary heart disease or ischemic heart disease Progressive reduction of blood supply to the heart muscle due to narrowing or blocking of a coronary artery (see atherosclerosis). in men. N Engl J Med 347:1755-60. |
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