Consuming Fruit and Its Effect on Diabetes Risk

Certain whole fruits lower the risk of type 2 diabetes as compared to other fruit sources….

The prospective longitudinal cohort study researchers drew from data on 66,105 women from the Nurses’ Health Study, 85,104 women from the Nurses’ Health Study II, and 36,173 men from the Health Professionals Follow-up Study. The participants did not present with any major chronic diseases at baseline in any of these studies.

The endpoint of the study was to determine the number of incident cases of type 2 diabetes, recognized through self-reports and then verified by additional questionnaires.

During follow-up on these participants, researchers found that 12,198 had developed type 2 diabetes. After all participants were adjusted for variable risk factors of diabetes, results found that the "hazard ratio of type 2 diabetes for every three servings/week of total whole fruit consumption was 0.98 (95% confidence interval 0.96 to 0.99)." Regarding the different types of fruit, the pooled hazard ratios of type 2 diabetes for every three servings/week were highest for cantaloupe (HR = 1.10) and lowest for blueberries (HR= 0.74). Every fruit was associated with a different risk of type 2 diabetes, some being higher and some being lower. Fruit juice consumption among the participants was associated with a hazard ratio of 1.08.

The authors commented that the difference in risk associated with each individual fruit may be due to the difference in fiber, antioxidant, and phytochemical content among the fruits.

The authors concluded that intake of "specific whole fruits," such as blueberries, grapes, and apples, is associated with a significantly lower risk of type 2 diabetes when compared to the intake of fruit juice or cantaloupe. Limitations of this study included its self-reported nature, which may have caused some misclassification of information as well as recall bias and residual confounding.

Muraki I, et al "Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies" BMJ 2013;347:f5001.