Vetten en de kans op een beroerte*
Uit een studie onder ruim 87.000 vrouwen in de leeftijd van 50-80 jaar blijkt dat het regelmatig eten van
vetten, in het algemeen als ook transvetten een verhoogde kans geeft op een beroerte als gevolg van een verstopt bloedvat. De vrouwen werden bijna 8 jaar gevolgd en ingedeeld in groepen afhankelijk van de hoeveelheid vetinname per dag. Zij in de groep met de hoogste vetinname van gemiddeld 86 gram per dag hadden 40% meer kans op een beroerte dan zij met de laagste inname van gemiddeld 26 gram per dag. De vrouwen in de groep met de meeste transvetten, gemiddeld 7 gram per dag hadden 30% meer kans op een beroerte dan zij met de laagste inname van gemiddeld 1 gram per dag. Transvetten worden vooral gevonden in kant en klare maaltijden, fastfood en gebakken en gefrituurde voeding.
Total Fat, Trans Fat Linked To Higher Incidence Of Ischemic Stroke
Post-menopausal women who reported consuming the most daily dietary fat had a 40 percent higher incidence of clot-caused strokes compared to women who ate the least amount, according to research presented at the American Stroke Association's International Stroke Conference 2010.
The incidence of ischemic stroke also increased by 30 percent in the quartile of women consuming the highest daily amount of trans fat (average intake 7 grams per day) compared to those who consumed the least (average 1 gram/day). Two common sources of trans fat are processed foods and fried foods.
Ischemic strokes are caused by blockages in blood vessels in or leading to the
brain.
"We found positive associations between total fat intake and ischemic stroke incidence and between trans fat intake and ischemic stroke incidence," said Sirin Yaemsiri, M.S.P.H., a doctoral student in the department of epidemiology in the Gillings School of Global Public Health at the University of North Carolina in Chapel
Hill.
The study is the first to examine the associations of different fats and different subtypes of ischemic stroke in post-menopausal women, who face a higher stroke risk than men of a similar age.
Evidence from other studies shows that different types of fat have different effects on the incidence of coronary heart disease (CHD), with trans fat implicated in the development of CHD. However, studies of ischemic stroke and fat have been inconclusive, possibly because earlier studies had small numbers of ischemic stroke cases.
Before menopause, women have a lower risk of stroke compared to men of similar age, a situation that reverses after menopause, Yaemsiri
said.
The analysis included data on 87,230 post-menopausal women ages 50 to 79 who participated in the Women's Health Initiative (WHI) Observational Study, a project sponsored by the National Institutes of Health and the National Heart, Lung and Blood Institute. The women answered a food frequency questionnaire when they entered the study and were followed for an average of 7.6 years, the researchers said. During that time, 1,049 ischemic strokes occurred.
Researchers looked for links between dietary fat intake and four ischemic stroke subtypes, which were characterized by their size or point of origin. However, the data on ischemic stroke subtypes fell short of statistical significance, perhaps because strokes are difficult to characterize and 43 percent (445 cases) of the ischemic strokes in the study were of unknown type, Yaemsiri said.
Researchers divided the women into quartiles based on the amount of total dietary fat and types of fat (saturated fat, monounsaturated fat, polyunsaturated fat and trans fat) they reported consuming per
day.
Variables included age, race, smoking status, physical activity, alcohol or aspirin use, body mass index, hormone therapy, heart disease history, diabetes, systolic blood pressure and whether the women took medication for high blood pressure or to reduce cholesterol, vitamin E supplementation, fruit/vegetable intake, total calories and dietary fiber.
Women in the top quartile for total fat intake had an average intake of 86 grams of total fat per day. Those in the lowest quartile consumed an average of 26 grams a
day.
"I think our findings support the American Heart Association recommendations for keeping trans fat intake at less than 1 percent of energy," said Ka He, M.D., Sc.D., M.P.H., senior author of the study and associate professor of nutrition and epidemiology at the UNC Gillings School of Global Public
Health.
Trans fats can be found in many foods - especially in fried foods like french fries and doughnuts, and baked goods including pastries, pie crusts, biscuits, pizza dough, cookies, crackers and stick margarines and shortenings.
Co-authors are Souvik Sen, M.D., M.S.; Lesley Tinker, Ph.D., R.D.; Wayne Rosamond, Ph.D.; and Sylvia Wassertheil-Smoller, Ph.D.
The WHI program is funded by the National Heart, Lung, and Blood Institute. This study was supported by a grant funded by the National Institute of Neurological Disorders and Stroke, and Yaemsiri's work was supported by an American Heart Association Mid-Atlantic Predoctoral Fellowship. Author disclosures are on the abstract.
Source
American Heart Association (Mei 2010)
