Lower Diabetes Risk With Whole Fruits Rather Than Fruit Juice
August 30, 2013

Lower Diabetes Risk With Whole Fruits Rather Than Fruit Juice

Michael Harper for redOrbit.com - Your Universe Online

Those looking to squeeze every ounce of health benefits from fruit may want to skip the juice, according to a study led by the Harvard School of Public Health.

Those who ate whole fruit saw their risk of Type 2 diabetes decrease, while those who drank their fruits instead saw their risk of the disease rise. Fruits like bananas, grapes, pears and prunes were all specifically mentioned in this study, but whole blueberries reduced a person’s risk of developing Type 2 the most, cutting their chances by 33 percent.

The researchers now say switching to whole fruit from juice is just another change people can make to decrease their Type 2 risk and live an overall healthier life. The resulting paper is published in the British Medical Journal.

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

The research team borrowed data from three, long-running American studies that gathered information from volunteers between 1984 and 2008. After excluding those volunteers who had already been diagnosed with cancer, cardiovascular disease or diabetes, the team was left with a total of 12,918 participants to study. They were particularly interested in what kinds of fruits these people ate and in what quantity. Apples, apricots, cantaloupes, oranges and strawberries were all listed as fruits the volunteers would eat whole. They also listed the types of fruit juice they liked to drink, such as apple, orange, grapefruit or some other kind of juice.

Those who reported eating only two servings of whole fruit each week were 23 percent less likely to be diagnosed with Type 2 than their peers who only took one serving of whole fruit each month. Those who took their fruits in juice form, however, saw their Type 2 risk increase by as much as 21 percent. Simply swapping three servings of juice each week with solid whole fruits could decrease a person’s diabetes risk by seven percent.

The researchers believe whole fruits have more of a health advantage because they pass through the digestive system more slowly. Fruit juice has a high glycemic index -- the amount a food can boost a person’s blood sugar levels -- but the researchers also say a fruit which has been juiced loses some essential nutrients which would otherwise be absorbed by the body.

"Fluids pass through the stomach to the intestine more rapidly than solids even if nutritional content is similar. For example, fruit juices lead to more rapid and larger changes in serum levels of glucose and insulin than whole fruits," wrote the authors, according to The Guardian.

When it comes to specific fruits, blueberries had the greatest effect on lowering the risk of Type 2 diabetes. Next in line were grapes and raisins. Those who reported eating these fruits instead of taking grape juice were 19 percent less likely to be diagnosed with Type 2. Switching from Apple juice to whole apples and pears could reduce the risk of diabetes by 14 percent. Finally, switching to either bananas or whole grapefruit could reduce the risk by 13 and 12 percent, respectively.

Though the researchers say further studies could be done, they’re confident in saying whole fruits can decrease Type 2 risk while fruit juice can increase the risk.

Recently, an Italian study found a Mediterranean diet can also decrease one’s diabetes risk. The researchers believe the monosaturated fats in olive oil, a central ingredient in the Mediterranean diet, could be the key to lowering insulin levels and therefore reducing diabetes risk.