Blueberries, grapes, and apples can lower the risk of developing type 2 diabetes, but you'll need to eat the whole fruit - rather than drinking fruit juice - to get their benefits, according to new research from the Harvard School of Public Health. The investigation was the first to look at the influence of specific fruits on the risk of the disease. The study team looked at total fruit consumption and at the influence of eating a variety of fruits including grapes or raisins; peaches, plums, or apricots; prunes; bananas; cantaloupe; apples or pears; oranges; grapefruit; strawberries; and blueberries. They also considered consumption of orange, grapefruit and apple juices as well as other fruit juices. The data they analyzed came from more than 187,000 health care professionals participating in three long-running studies. None of the participants had any type of major chronic disease when they enrolled in the studies. The Harvard team found that the risk of developing type 2 diabetes among individuals who ate at least two weekly servings of blueberries, grapes and apples was 23 percent lower than it was in study participants who ate less than one serving of fruit per month. Those who drank one or more servings of fruit juice daily had a 21 percent increased risk of developing type 2 diabetes.
My take? There’s a big difference between fruit and fruit juice. Fruit juice is a concentrated sugar source that can promote insulin resistance and obesity, especially when consumed in quantity, so I’m not surprised by the new study’s findings. Interestingly, the report also showed that switching from fruit juice to whole fruit lowers the risk of type 2 diabetes by at least seven percent. Another effective strategy to lower your risk is to avoid carbohydrate foods high on the glycemic index, the measure of how rapidly the body converts them into glucose, provoking an insulin response. Reducing or eliminating your intake of alcoholic beverages will also help. The body burns calories from alcohol immediately, increasing the likelihood that those from the food you eat along with alcoholic drinks will be stored as fat.
Qi Sun and Isao Muraki et al, “Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies,“ BMJ, online August 29, 2013