High cereal fibre but not total fibre is associated with a lower risk of type 2 diabetes: Evidence from Melbourne Collaborative Cohort Study.

AIM: With growing evidence on the roles of fibre from different food sources on health, we aimed to assess the associations of total dietary and fibre from different food sources (i.e., cereal, fruit, and vegetable) with the risk of diabetes.

MATERIALS AND METHODS: The Melbourne Collaborative Cohort Study (MCCS) enrolled 41 513 participants 40-69 years of age from 1990 to 1994. The first and second follow-ups were conducted in 1994-1998 and 2003-2007, respectively. Self-reported diabetes incidence was recorded at both follow-ups. We analyzed data from 39 185 participants with a mean of 13.8 years follow-up. The relationships between dietary fibre intake (total, fruit, vegetable, and cereal fibre) and the incidence of diabetes were assessed using modified Poisson regression, adjusted for dietary, lifestyle, obesity, socioeconomic and other possible confounders. Fibre intake was categorized into quintiles.

RESULTS: At total of 1989 incident cases were identified over both follow-up surveys. Total fibre intake was not associated with diabetes risk. Higher intake of cereal fibre (p for trend = 0.003, but not fruit (p for trend = 0.3) and vegetable (p for trend =0.5) fibre, was protective against diabetes. For cereal fibre, quintile 5 versus quintile 1 showed a 25 % reduction in diabetes risk (Incidence risk ratio (IRR) =0.75 (95% CI: 0.63-0.88)). For fruit fibre, only quintile 2 versus quintile 1 showed a 16% risk reduction (IRR = 0.84 [95% CI: 0.73-0.96]). Adjustment for BMI and WHR eliminated the association and mediation analysis showed, BMI mediated 36% of the relationship between fibre and diabetes.

CONCLUSION: Intake of cereal fibre and, to a lesser extent, fruit fibre may reduce the risk of diabetes, while total fibre showed no association. Our data suggest that specific recommendations regarding dietary fibre intake may be needed to prevent diabetes. This article is protected by copyright. All rights reserved.