Diet Rendah Karbohidrat dan Risiko Penyakit Jantung Koroner untuk Wanita

Diet rendah karbohidrat (low carb) banyak digunakan untuk menurunkan berat badan dan mencegah obesitas. Bagaimana efek diet low carb terhadap risiko penyakit jantung koroner (PJK)?

Penelitian yang melibatkan >82 ribu subyek dan difollow-up selama 20 tahun, menyimpulkan terhadap risiko terjadinya PJK, diet low carb ataupun diet low fat ternyata tidak berbeda. Kedua jenis diet - low carb maupun low fat - mempunyai kelebihan dan kekurangan masing2.

Temuan terpenting adalah bahwa dengan memperbanyak sayuran dalam diet (sebagai sumber protein nabati dan lemak nabati) risiko PJK dapat diturunkan sebesar 30%. Sebaliknya konsumsi karbohidrat ber-indeks glisemik rendah (misalnya gula) akan meningkatkan risiko PJK.

New England Journal of Medicine number 19, Volume 355:1991-2002. Low-Carbohydrate-Diet Score and the Risk of Coronary Heart Disease in Women. Thomas L. Halton, Sc.D., Walter C. Willett, M.D., Dr.P.H., Simin Liu, M.D., Sc.D., JoAnn E. Manson, M.D., Dr.P.H., Christine M. Albert, M.D., M.P.H., Kathryn Rexrode, M.D., and Frank B. Hu, M.D., Ph.D.

ABSTRACT

Background Low-carbohydrate diets have been advocated for weight loss and to prevent obesity, but the long-term safety of these diets has not been determined. Methods We evaluated data on 82,802 women in the Nurses' Health Study who had completed a validated food-frequency questionnaire. Data from the questionnaire were used to calculate a low-carbohydrate-diet score, which was based on the percentage of energy as carbohydrate, fat, and protein (a higher score reflects a higher intake of fat and protein and a lower intake of carbohydrate). The association between the low-carbohydrate-diet score and the risk of coronary heart disease was examined. Results During 20 years of follow-up, we documented 1994 new cases of coronary heart disease. After multivariate adjustment, the relative risk of coronary heart disease comparing highest and lowest deciles of the low-carbohydrate-diet score was 0.94 (95% confidence interval [CI], 0.76 to 1.18; P for trend=0.19). The relative risk comparing highest and lowest deciles of a low-carbohydrate-diet score on the basis of the percentage of energy from carbohydrate, animal protein, and animal fat was 0.94 (95% CI, 0.74 to 1.19; P for trend=0.52), whereas the relative risk on the basis of the percentage of energy from intake of carbohydrates, vegetable protein, and vegetable fat was 0.70 (95% CI, 0.56 to 0.88; P for trend=0.002). A higher glycemic load was strongly associated with an increased risk of coronary heart disease (relative risk comparing highest and lowest deciles, 1.90; 95% CI, 1.15 to 3.15; P for trend=0.003).

Conclusions Our findings suggest that diets lower in carbohydrate and higher in protein and fat are not associated with increased risk of coronary heart disease in women. When vegetable sources of fat and protein are chosen, these diets may moderately reduce the risk of coronary heart disease.

Source Information From the Departments of Nutrition (T.L.H., W.C.W., F.B.H.) and Epidemiology (W.C.W., J.E.M., F.B.H.), Harvard School of Public Health, Boston; the Department of Epidemiology, University of California, Los Angeles, School of Public Health, Los Angeles (S.L.); and the Division of Preventive Medicine (J.E.M., C.M.A., K.R.), the Channing Laboratory (W.C.W., J.E.M., K.R., F.B.H.), and the Cardiovascular Division (C.M.A.), Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston.

Untung Rugi Konsumsi Seafood

Para peneliti dari Harvard ingin mengetahui keuntungan dan kerugian konsumsi seafood.

Ternyata konsumsi seafood (terutama ikan yang kaya asam lemak omega-3 berupa DHA maupun EPA) sebanyak 1-2 porsi tiap minggu dapat menurunkan angka kematian penyakit jantung koroner sebesar 36%.

DHA mendukung perkembangan awal sel2 saraf, sehingga ibu hamil dan menyusui dianjurkan untuk konsumsi seafood 2 porsi tiap minggu. Kontaminasi metil-merkuri sebaliknya menghambat perkembangan sel2 saraf, namun pengaruh metil-merkuri untuk orang dewasa kurang nyata.

Dianjurkan mengkonsumsi beragam jenis seafood.

Kadar kontaminasi dioxin dan polychlorinated biphenyls terdeteksi rendah, sehingga potensi karsinogeniknya juga rendah.

Disimpulkan bahwa keuntungan konsumsi beragam seafood lebih besar dibanding efek negatifnya, termasuk untuk kelompok wanita usia subur.

Catatan untuk seafood dari perairan dengan tingkat kontaminasi lebih tinggi, kesimpulan di atas mungkin tidak berlaku.

Abstract

JAMA <http://jama.ama-assn.org/cgi/content/abstract/296/15/1885?etoc><http://jama .ama-assn.org/cgi/content/abstract/296/15/1885?etoc> 2006;296:1885-1899. Vol. 296 No. 15, October 18, 2006 © 2006 American Medical Association. Fish Intake, Contaminants, and Human Health: Evaluating the Risks and the Benefits. Dariush Mozaffarian, Eric B. Rimm.

Context Fish (finfish or shellfish) may have health benefits and also contain contaminants, resulting in confusion over the role of fish consumption in a healthy diet. Evidence Acquisition We searched MEDLINE, governmental reports, and meta-analyses, supplemented by hand reviews of references and direct investigator contacts, to identify reports published through April 2006 evaluating (1) intake of fish or fish oil and cardiovascular risk, (2) effects of methylmercury and fish oil on early neurodevelopment, (3) risks of methylmercury for cardiovascular and neurologic outcomes in adults, and (4) health risks of dioxins and polychlorinated biphenyls in fish. We concentrated on studies evaluating risk in humans, focusing on evidence, when available, from randomized trials and large prospective studies. When possible, meta-analyses were performed to characterize benefits and risks most precisely. Evidence Synthesis Modest consumption of fish (eg, 1-2 servings/wk), especially species higher in the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), reduces risk of coronary death by 36% (95% confidence interval, 20%-50%; P<.001) and total mortality by 17% (95% confidence interval, 0%-32%; P = .046) and may favorably affect other clinical outcomes. Intake of 250 mg/d of EPA and DHA appears sufficient for primary prevention. DHA appears beneficial for, and low-level methylmercury may adversely affect, early neurodevelopment. Women of childbearing age and nursing mothers should consume 2 seafood servings/wk, limiting intake of selected species. Health effects of low-level methylmercury in adults are not clearly established; methylmercury may modestly decrease the cardiovascular benefits of fish intake. A variety of seafood should be consumed; individuals with very high consumption (5 servings/wk) should limit intake of species highest in mercury levels. Levels of dioxins and polychlorinated biphenyls in fish are low, and potential carcinogenic and other effects are outweighed by potential benefits of fish intake and should have little impact on choices or consumption of seafood (women of childbearing age should consult regional advisories for locally caught freshwater fish). Conclusions For major health outcomes among adults, based on both the strength of the evidence and the potential magnitudes of effect, the benefits of fish intake exceed the potential risks. For women of childbearing age, benefits of modest fish intake, excepting a few selected species, also outweigh risks.

Author Affiliations: Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School; and Departments of Epidemiology and Nutrition, Harvard School of Public Health, Boston, Mass.

Kopi, diabetes dan berat badan

Beberapa penelitian epidemiologi menyimpulkan bahwa kopi (baik caffeinated maupun decaffeinated) dapat mengurangi risiko diabetes. Ini mungkin berhubungan dengan penurunan berat badan. Penurunan berat badan diduga berhubungan dengan kandungan kafein dan zat2 lain dalam kopi (chlorogenic acid dan quinides). Namun kopi dapat menyebabkan kenaikan tekanan darah akut sehingga ditakutkan akan meningkatkan risiko penyakit kardiovaskuler. Satu penelitian singkat menyimpulkan bahwa kopi decaffeinated tidak menaikan tekanan darah. Dengan demikian konsumsi kopi decaffeinated lebih aman dan tetap dapat mengurangi risiko diabetes.

Abstract

American Journal of Clinical Nutrition, Vol. 84, No. 4, 682-693, October 2006 © 2006 American Society for Nutrition. Coffee, diabetes, and weight control. James A Greenberg, Carol N Boozer and Allan Geliebter. From the Department of Health and Nutrition Sciences, Brooklyn College, City University of New York, New York NY (JAB), and the Department of Medicine, Columbia University and New York Obesity Research Center, St Luke's-Roosevelt Hospital Center, New York, NY (NB and AG) Several prospective epidemiologic studies over the past 4 y concluded that ingestion of caffeinated and decaffeinated coffee can reduce the risk of diabetes. This finding is at odds with the results of trials in humans showing that glucose tolerance is reduced shortly after ingestion of caffeine or caffeinated coffee and suggesting that coffee consumption could increase the risk of diabetes. This review discusses epidemiologic and laboratory studies of the effects of coffee and its constituents, with a focus on diabetes risk. Weight loss may be an explanatory factor, because one prospective epidemiologic study found that consumption of coffee was followed by lower diabetes risk but only in participants who had lost weight. A second such study found that both caffeine and coffee intakes were modestly and inversely associated with weight gain. It is possible that caffeine and other constituents of coffee, such as chlorogenic acid and quinides, are involved in causing weight loss. Caffeine and caffeinated coffee have been shown to acutely increase blood pressure and thereby to pose a health threat to persons with cardiovascular disease risk. One short-term study found that ground decaffeinated coffee did not increase blood pressure. Decaffeinated coffee, therefore, may be the type of coffee that can safely help persons decrease diabetes risk. However, the ability of decaffeinated coffee to achieve these effects is based on a limited number of studies, and the underlying biological mechanisms have yet to be elucidated.