Sodas and Other Sweet Drinks Raise the Risk of Diabetes

People who down a couple of sugary drinks each day do more than quench their thirst — they run the risk of developing type 2 diabetes.

According to a new study, men and women who toss back one or two sugar-sweetened drinks a day — including soft drinks, sweet tea, energy drinks and fruit drinks (but not fruit juice) — are 26 percent more likely to develop type 2 diabetes and 20 percent more likely to develop metabolic syndrome than those who drink no more than one a month or none at all. Metabolic syndrome is a cluster of conditions that increase the risk of diabetes and heart disease; they include high blood pressure, belly fat and high blood sugar.

Drinking just one 12-ounce serving a day is associated with a 15 percent higher rate of diabetes.

Researchers at the Harvard School of Public Health analyzed 11 studies. Eight of them, with a total of more than 300,000 participants, looked for a link between sugary drinks and diabetes. Three studies, with more than 19,000 participants, sought a connection with metabolic syndrome.

The weight gain that goes hand in hand with excess calories may partially explain the link with metabolic syndrome and diabetes. After all, a typical 12-ounce can of soda or bottle of sweetened iced tea packs a hefty 150 calories and the equivalent of 10 packets of sugar. But the researchers found this relationship persisted even after adjusting for calories, which led them to conclude that sugary drinks are a risk factor for both conditions independent of weight gain.

The tactic of substituting artificially sweetened drinks for sugary ones seems to make sense, but chances are it may backfire. One study revealed an association between drinking artificially sweetened beverages and gaining weight, which raises the bothersome question of whether these drinks might be fueling rather than fighting the accumulation of unwanted pounds.

In addition, "Not many studies have looked at the long-term health effects of artificial sweeteners," says epidemiologist Frank Hu, M.D., lead author of the Harvard study, "so I don't think they're the best replacements for regular soda." Hu suggests giving plain water a chance. If you don't like it straight from the tap, try chilled sparkling water with a slice of lemon or lime.

"Although the number of studies included in this analysis is small, the results emphasize the kind of common-sense position we should take," says endocrinologist Robert Eckel, M.D., of the University of Colorado Hospital. "An occasional sugar-sweetened soda or juice drink is OK but drinking them to excess contributes to obesity, which in turn can lead to both diabetes and heart disease." Eckel, past president of the American Heart Association, was not involved in the study.

The study is in the November issue of the journal Diabetes Care.

Nissa Simon, who lives in New Haven, Conn., writes about nutrition and medical issues.