The common admonishment for children to eat their fruits and vegetables may have more truth behind it than most common food adages. A new study from researchers at the Harvard School of Public Health has partially confirmed the saying, linking fruits to a lowered risk of type 2 diabetes.

The study, published in the British Medical Journal, looked at the fruit consumption habits of 187,382 people from a variety of studies conducted between 1984 and 2008. Researchers found that participants who ate more whole fruits such as grapes, apples, and blueberries were at a lower risk for developing type 2 diabetes than those who ate less whole fruits. The study also found that fruit juice alone was associated with a greater risk for type 2 diabetes.

“While fruits are recommended as a measure for diabetes prevention, previous studies have found mixed results for total fruit consumption,” said Qi Sun, a co-author of the study and a nutrition professor at the Harvard School of Public Health. “Our findings provide novel evidence suggesting that certain fruits may be especially beneficial for lowering diabetes risk.”

The study found that those who ate at least two servings of whole fruits per week reduced their diabetes risk by up to 23% over those who ate only one serving of whole fruit per month or less. Those who drank one or more servings of fruit juice per day had an increased type 2 diabetes risk of up to 21%.

Researchers stated that the high sugar content of fruit juice could explain its association with diabetes. However, of the whole fruits studied (grapes, grapefruit, oranges, strawberries, blueberries, peaches, plums, pears, apples, bananas, apricots, and cantaloupe) sugar content was not significantly associated with diabetes.

“Our data further endorse current recommendations on increasing whole fruits, but not fruit juice, as a measure for diabetes prevention,” said Isao Muraki, lead author of the study and a nutrition research fellow at Harvard. “And our novel findings may help refine this recommendation to facilitate diabetes prevention.”