Eating Whole Fruits Lowers Risk for Type 2 Diabetes

If you want to reduce your risk for type 2 diabetes, think about adding apples, grapes and blueberries to your grocery list. You also might want to limit the number of fruit juices in your shopping cart.

This recommendation is the result of research done through the Harvard School of Public Health. Researchers looked at data obtained from 187,382 participants in three long-term studies that ran from 1984 to 2008.

The Fruits of the Harvard Study

The findings of this study were recently published in the British Medical Journal.

1. People who enjoyed a minimum of two servings per week of specific whole fruits – particularly grapes, blueberries and apples – lowered their risk of developing type 2 diabetes by up to 23 percent, compared to those who had less than one serving each month.
2. Those who drank one or more fruit juice servings per day raised their type 2 diabetes risk up to 21 percent.
3. By swapping three fruit juice servings each week for whole fruits, individuals lowered their diabetes risk 7 percent.

Fruit juices are more quickly absorbed into the body than are fiber-rich whole fruits; this might explain why diabetes risk increases with juice consumption.

The researchers also theorize that berries and grapes may owe some of their beneficial effects to an anthocyanin component. Anthocyanins have been associated with reduced heart attack risk, and may have something to do with lowering the risk for diabetes; more research is naturally required.

How The Study Was Conducted

Research subjects with a reported diagnosis of cardiovascular disease, cancer or diabetes at the time of their study enrollment were excluded from the Harvard study. Of the individuals remaining, 12,198 (6.5 percent) developed diabetes as their study progressed.

The Harvard sleuths examined participants' overall intake of fruit and made note of the specific fruits they ate. These fruits included peaches, plums, grapes or raisins, apricots, prunes, cantaloupe, bananas, pears or apples, grapefruit, oranges, blueberries and strawberries. Participants’ consumption of fruit juice was also scrutinized.

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

Source: Harvard School of Public Health

Photo of pears and plums by John Nyboer