September 2013

Blueberries, Apples, Grapes May Reduce Diabetes Risk

A new study suggests that eating more fruit, particularly blueberries, grapes and apples, but not drinking fruit juice, may reduce diabetes risk.

Fruit add a variety of necessary vitamins and minerals to the diet. All fruits vary in nutritional value and some may be more beneficial for certain conditions than others. Blueberries have high antioxidant levels due to the presence of anthocyanins, which are the pigments many plants produce to attract the birds and insects necessary for pollination. Limited research suggests that blueberries may be useful in lowering glucose (blood sugar) or modifying other factors associated with diabetes. Grapes have been shown to possess antioxidant, blood clot-preventing, and cholesterol-lowering properties. Additionally, some studies suggest that apples may help slow cancer development and manage diabetes. Fruit juice may not be beneficial substitutes for eating whole fruits as they are often high in added sugars.

In a recent study, researchers evaluated data on 151,209 healthy women from the Nurses' Health Study and the Nurses' Health Study II, as well as data on 36,173 healthy men from the Health Professionals Follow-up Study to assess the potential association between fruit consumption and diabetes risk. Throughout the 3,464,641 person years follow-up period, 12,198 participants developed diabetes.

After adjusting the data for various factors, the researchers found that for every three weekly servings of blueberries, grapes, and apples diabetes risk reduced by 26 percent, 12 percent and seven percent, respectively. The authors noted that the risk for diabetes differed significantly for individual fruits. General fruit consumption was linked to an overall two percent reduced risk of diabetes. Conversely, drinking fruit juice was linked to an eight percent increased risk.

The authors concluded that some fruits may be more beneficial than others for reducing diabetes risk, and that drinking fruit juice may actually result in an increased risk. Further research is warranted in this area.

In addition to blueberries, apples and grapes, there is also evidence that suggests guar gum may be effective in reducing blood sugar levels in people with types 1 and 2 diabetes. However, results are not consistent, and more research is needed before further conclusions can be made.

For more information about integrative therapies for diabetes, please visit Natural Standard's Comparative Effectiveness Database.

For more information about blueberries, apples or grapes, please visit Natural Standard's Foods, Herbs & Supplements Database.

To comment on this story, please visit Natural Standard's blog.


  1. Muraki I, Imamura F, Manson JE, et al. Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies. BMJ. 2013 Aug 28;347:f5001. 
  2. Natural Standard: The Authority on Integrative Medicine. 

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