Fruits and the Risk of Type 2 Diabetes: The Korean Genome and Epidemiology Study Cohort.

Background: To determine the association between type 2 diabetes mellitus and the consumption of various fruits.

Methods: The Korean Genome And Epidemiology Study is an ongoing prospective longitudinal cohort study of community dwellers and participants (men and women, aged 40-69 years) recruited from the national health examinee registry of Korea. Their individual consumption habits for 12 different fruit types were recorded using food frequency questionnaires. The fruits were then divided into three groups according to their glycemic indexes and glycemic loads. Participants with extreme caloric intakes, pre-existing type 2 diabetes mellitus, chronic kidney diseases, chronic liver diseases, and ongoing cancer treatments were excluded. The incidence of type 2 diabetes in the cohort was identified through self-reporting and supplemented by glycated hemoglobin and fasting blood glucose levels.

Results: A total of 2,549 cases of type 2 diabetes were documented during 283,033.8 person-years of follow-up. After adjusting for personal, lifestyle, and dietary risk factors for diabetes, the pooled hazard ratio of type 2 diabetes for every serving per week of total whole fruit consumption was 1.02 (95% confidence interval [CI], 0.99-1.06; P=0.2). With mutual adjustment of individual fruits, the pooled hazard ratios of type 2 diabetes for every serving per week were 0.94 (95% CI, 0.88-1.00; P=0.039) for bananas, and 0.90 (95% CI, 0.84-0.96; P<0.001) for grapes.

Conclusion: Our findings suggest associations between the consumption of certain fruits and the risk of developing type 2 diabetes. A greater consumption of grapes was significantly associated with a lower risk of type 2 diabetes in our cohort, but the total amount of fruit consumption was not associated with a reduced risk.