Background: Type 2 diabetes is a major health concern worldwide. Whole grains and cereal fiber may offer protective effects on type 2 diabetes risk. However, few studies have been conducted in cohorts with detailed information on whole-grain cereal intakes and product types and with wide ranges of intake.
Objective: We investigated the associations between whole-grain intake, including intakes of different cereal types and products, and the risk of type 2 diabetes in a population with wide and diverse whole-grain intake.
Methods: We used data from the Danish Diet, Cancer, and Health cohort including 55,465 participants aged 50-65 y at baseline. Of these, 7417 participants were diagnosed with type 2 diabetes during follow-up (median: 15 y). Detailed information on the intake of whole-grain products was available from a food-frequency questionnaire, and total whole-grain intake and whole-grain cereal types (wheat, rye, oats) were calculated in grams per day. Associations were examined by using Cox proportional hazards models with adjustment for potential confounders.
Results: Whole-grain intake was associated with an 11% and 7% lower risk of type 2 diabetes per whole-grain serving (16 g) per day for men and women, respectively [HR (95% CI)-men: 0.89 (0.87, 0.91); women: 0.93 (0.91, 0.96)]. For men, the intake of all whole-grain cereal types investigated (wheat, rye, oats) was significantly associated with a lower risk of type 2 diabetes, but only wheat and oats intake was significantly associated for women. Among the different whole-grain products, rye bread, whole-grain bread, and oatmeal/muesli were significantly associated with a lower risk of type 2 diabetes for both men and women.
Conclusions: In this cohort study, we found consistent associations between high whole-grain intake and lower risk of type 2 diabetes. Overall, an association was found for all different cereals and whole-grain products tested.