1.
Intake of vegetables rich in carotenoids and risk of coronary heart disease in men: The Physicians' Health Study.
Liu, S, Lee, IM, Ajani, U, Cole, SR, Buring, JE, Manson, JE, ,
International journal of epidemiology. 2001;(1):130-5
Abstract
BACKGROUND Previous studies of diet and coronary heart disease (CHD) have focused on intake of nutrients rather than whole foods. Because of the findings that dietary fibre, folate and antioxidants may be protective for CHD, increased intake of vegetables has been recommended. However, due to the chemical and physical complexity of vegetables, the effects of individual nutrients may differ if eaten as whole foods. Moreover, little is known about the direct association between vegetable intake and risk of CHD. METHODS We prospectively evaluated the relation between vegetable intake and CHD risk in the Physicians' Health Study, a randomized trial of aspirin and beta-carotene among 22 071 US male physicians aged 40-84 years in 1982. In this analysis, we included 15 220 men without heart disease, stroke or cancer at baseline who provided information on their vegetable intake at baseline, and in the 2nd, 4th and 6th years of follow-up using a simple semiquantitative food frequency questionnaire including eight vegetables. We confirmed 1148 incident cases of CHD (387 incident cases of myocardial infarction and 761 incident cases of coronary artery bypass grafting or percutaneous transluminal coronary angioplasty) during 12 years of follow-up. RESULTS After adjusting for age, randomized treatment, body mass index (BMI), smoking, alcohol intake, physical activity, history of diabetes, history of hypertension, history of high cholesterol, and use of multivitamins, men who consumed at least 2.5 servings/day of vegetables had a relative risk (RR) of 0.77 (95% CI : 0.60-0.98) for CHD, compared with men in the lowest category (<1 serving/day). Adjusting for the same covariates in an analysis of the overall trend that considered intake of vegetables as a continuous variable, we found a RR of 0.83 (95% CI : 0.71-0.98) for risk of CHD for each additional serving/day of vegetables. The inverse relation between vegetable intake and CHD risk was more evident among men with a BMI > or =25 (RR = 0.71, 95% CI : 0.51-0.99) or current smokers (RR = 0.40, 95% CI : 0.18-0.86) comparing highest to the lowest categories of intake. CONCLUSIONS Our results suggest an inverse association between vegetable intake and risk of CHD. These prospective data support current dietary guidelines to increase vegetable intake for the prevention of CHD.
2.
Dietary carbohydrates, physical inactivity, obesity, and the 'metabolic syndrome' as predictors of coronary heart disease.
Liu, S, Manson, JE
Current opinion in lipidology. 2001;(4):395-404
Abstract
Several decades of epidemiological and clinical research have identified physical inactivity, excessive calorie consumption, and excess weight as common risk factors for both type 2 diabetes mellitus and coronary heart disease. This trio forms the environmental substrate for a now well-recognized metabolic phenotype called the insulin resistance syndrome. Recent data suggest that a high intake of rapidly absorbed carbohydrates, which is characterized by a high glycemic load (a measure of carbohydrate quality and quantity), may increase the risk of coronary heart disease by aggravating glucose intolerance and dyslipidemia. These data also suggest that individuals who are obese and insulin resistant are particularly prone to the adverse effects of a high dietary glycemic load. In addition, data continue to accumulate suggesting the important beneficial effects of physical activity, even at moderate levels, and weight reduction on improving insulin sensitivity and reducing the risk of coronary heart disease. Future metabolic studies should continue to quantify the physiological impact of different foods on serum glucose and insulin, and such information should routinely be incorporated into large-scale and long-term prospective studies, in which the possible interaction effects between diet and other metabolic determinants such as physical activity and obesity can be examined. Until more definitive data are available, replacing refined grain products and potatoes with minimally processed plant-based foods such as whole grains, fruits, and vegetables, and reducing the intake of high glycemic load beverages may offer a simple strategy for reducing the incidence of coronary heart disease.