Whole Fruit—Not Juice—Lowers Diabetes Risk

A new study published in the British Medical Journal finds that regular consumption of whole fruits significantly lowers type 2 diabetes risk in adults, as compared to people who eat little fruit. The effect was not observed for fruit juices—on the contrary, the cohort study found that people who drink a lot of fruit juice have an increased risk of developing type 2 diabetes.

The findings underscore the need for whole foods in the diet, which are well known to boost fiber intake much more effectively than supplements or their pureed or juiced counterparts. Fiber, of course, is a cholesterol-lowering component of the healthiest foods, and can help curb appetite and remove fat from the body. It has also been long understood that, while fortified foods, vitamin pills, and non-whole food supplements may have their place in the diet, the nutritional value of whole, fresh foods is still the most enviable; the body is simply better at vitamin and mineral absorption when foods are fresh and consumed in minimally cooked or processed ways. Whole fruit, of course, is mostly raw.

The fruits that the researchers concluded were most effective at mitigating diabetes risk included apples, grapes, blueberries, raisins, pears, bananas, and grapefruit.

In the study, three cohorts of U.S. healthcare professionals were asked to fill out dietary questionnaires that specifically sought information on “food frequency.” The total population of subjects in the end comprised nearly 190,000 adults, all of whom were without diabetes at baseline. Over 12,000 people eventually developed type 2 diabetes. Total years of follow up were some 3.5 million person-years.

The risk for diabetes was significantly reduced with every three servings per week of blueberries (hazard ratio, 0.74), grapes and raisins (0.88), apples and pears (0.93), bananas (0.95), and grapefruit (0.95). Consumption of one or more servings daily of fruit juice, on the other hand, was associated with increased diabetes risk.

Many diabetes sufferers are reticent about consuming large amounts of whole or juiced fruit regularly; it is a food item at times associated with fixing an acute hypoglycemic reaction, when diabetes patients feel they are in need of a quick jolt of fructose. The fact that fruit, which can be high in sugar, may at times undesirably spike blood glucose levels is worth remembering. But this comprehensive cohort study should do much to allay fears that whole fruit is a bane on blood-sugar regulation for people wishing to avoid diabetes onset. On the other hand, it is a long-term dietary preventive measure that deserves more attention for its natural, simple, and inexpensive advantages.

BMJ, Aug. 2013, 347:f5001,http://www.bmj.com/content/347/bmj.f5001

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