Devil is in the details
To look at potential connections between eating fruit and type 2 diabetes risk, researchers collected information on diet, physical activity, height, weight, cigarette smoking, and history of heart disease, diabetes, or cancer from 187,382 middle-aged men and women. Each participant was followed for between 18 and 24 years, and the study authors noted which people developed type 2 diabetes.
Compared with people eating less fruit, those who ate three or more weekly servings of apples and pears, bananas, blueberries, grapefruit, grapes and raisins, or total fruit were significantly less likely to develop type 2 diabetes. Certain types of fruit seemed to reduce risk particularly well when consumed at least three times weekly, including
blueberries, which reduced risk by 26%,
grapes and raisins, which reduced risk by 12%,
apples and pears, which reduced risk by 7%, and
bananas and grapefruit, which each reduced risk by 5%.
Factoring in fruit to manage diabetes risk
While this study is observational, and therefore cannot prove cause and effect, it provides useful ideas about which fruit may be particularly beneficial for fending off type 2 diabetes, and it gives us a window into why previous studies, which only considered total fruit, have yielded conflicting results. While this study suggests that total fruit may reduce risk, it is possible that specific types of fruit have a more powerful effect than others.
Still, according to study author Qi Sun, epidemiologist and professor in the Department of Nutrition at Harvard's School of Public Health, "We don't want to leave the impression that there's any magical fruit," because this study only shows associations, not proof that certain fruits are the silver bullet for type 2 diabetes. To protect your health, a multifaceted approach is best:
- Put family first. Type 2 diabetes runs in families, so if you have a family history of the disease, talk to your doctor about how to best manage your increased risk.
- Fruit up. Nutritionists have long advised people to choose whole fruit over fruit juice, and this makes sense. Juice lacks the fiber of whole fruit, and fiber plays a role in keeping glucose levels stable and reducing caloric intake.
- Move muscle. When you move your body, your muscles use insulin more efficiently. Even if you don't lose a pound, you're still improving your odds of avoiding type 2 diabetes. Try 20 to 30 minutes of brisk walking, biking, or most any other aerobic activity daily to improve glucose control.
- Vegetate. Vegetables may be even more beneficial than fruit, because they pack many of the same nutrients--and more--without even close to the amount of simple sugar found in fruit.
- Berry on. Berries are chock full of nutrients known to have beneficial effects on health, so eat blueberries, blackberries and raspberries in season (picking fruit with kids is a fun outdoor activity) and opt for frozen when fresh is not available.
(BMJ 2013;347:f5001 doi: 10.1136/bmj.f5001)