OBJECTIVE -To examine associations between type 2 diabetes and fiber, glycemic load (GL), dietary glycemic index (GI), and fiber-rich foods.RESEARCH DESIGN AND METHODS -This was a prospective study of 36,787 men and women aged 40 -69 years without diabetes. For all self-reported cases of diabetes at 4-year follow-up, confirmation of diagnosis was sought from medical practitioners. Case subjects were those who reported diabetes at follow-up and for whom there was no evidence that they did not have type 2 diabetes. Data were analyzed with logistic regression, adjusting for country of birth, physical activity, family history of diabetes, alcohol and energy intake, education, 5-year weight change, sex, and age.RESULTS -Follow-up was completed by 31,641 (86%) participants, and 365 cases were identified. The odds ratio (OR) for the highest quartile of white bread intake compared with the lowest was 1.37 (95% CI 1.04 -1.81; P for trend ϭ 0.001). Intakes of carbohydrate (OR per 200 g/day 0.58, 0.36 -0.95), sugars (OR per 100 g/day 0.61, 0.47-0.79), and magnesium (OR per 500 mg/day 0.62, 0.43-0.90) were inversely associated with incidence of diabetes, whereas intake of starch (OR per 100 g/day 1.47, 1.06 -2.05) and dietary GI (OR per 10 units 1.32, 1.05-1.66) were positively associated with diabetes. These relationships were attenuated after adjustment for BMI and waist-to-hip ratio.CONCLUSIONS -Reducing dietary GI while maintaining a high carbohydrate intake may reduce the risk of type 2 diabetes. One way to achieve this would be to substitute white bread with low-GI breads.
Diabetes Care 27:2701-2706, 2004T he prevalence of type 2 diabetes is increasing rapidly worldwide, hence the need for widely applicable strategies to reduce incidence (1). Intensive interventions focusing on diet, physical activity, and weight loss have reduced or delayed the incidence of type 2 diabetes in high-risk individuals (2-5). Such interventions are not feasible at the population level, but the dramatic change from butter to margarine in Australia during the 1970s (6) suggests that relatively small changes from one version of a food to another may be achievable.Current Australian dietary recommendations promote the consumption of cereal products (7); however, some studies suggest that refined or high-glycemic index (GI) cereal products may increase the risk of diabetes (8 -10), and benefits from cereal products may relate only to whole grains or cereal fiber (8,9,(11)(12)(13). It is important to clarify the associations between cereals, GI, glycemic load (GL), and fiber and type 2 diabetes so that, if necessary, recommendations can be made more specific.Our aims were, therefore, to examine the associations between type 2 diabetes and fiber, GL, GI, and fiber-rich foods in a prospective study in Melbourne, Australia.RESEARCH DESIGN AND METHODS -The Melbourne Collaborative Cohort Study recruited 41,528 people (17,049 men) between 1990 and 1994. The subjects' age range was 27-75 years at baseline (99.3% were 40 -69 years of age). The study in...