Drinking soda increases risk of diabetes, metabolic syndrome

A large study published in Diabetes Care found that people who had a soda or two a day, compared to people who one sugary drink a month, had a 26 percent increased risk of diabetes, and a 20 percent increased risk of metabolic syndrome.

When researchers adjusted for body mass, those numbers fell – but only by about half, which means even slim people can get diabetes if they regularly consume sugary drinks: soda, sweetened tea, sports drinks, “juice” drinks, vitamin waters, and “energy” drinks.

In fact, drinking just one 12-ounce serving of soda per day increased a person's risk for type 2 diabetes by about 15%.

The meta-analysis pooled data from 11 studies that involved more than 300,000 participants with 15,043 cases of type 2 diabetes and 19,431 participants with 5,803 cases of metabolic syndrome. Participants were followed from four to 20 years.

“What’s really important is a very clear, significant positive association with the risk of type 2 diabetes,” said researcher Vasanti Malik, ScD, a fellow in the nutrition department at the Harvard School of Public Health. “There are a lot of factors that contribute to type 2 diabetes, but this is one modifiable factor that would be very easy for people to change.”

The kinds of drinks or the kinds of sugar - sucrose, high-fructose corn syrup, or fruit juice concentrates – were not studied separately, but the authors say their metabolic effects are essentially the same. A 100 percent juice drink is not considered sugar-sweetened.

The American Beverage Association disputed the study’s results. “It is overly simplistic, and simply misleading, to suggest that reducing or eliminating sugar-sweetened beverages from the diet will uniquely lower incidence of serious health conditions such as diabetes or metabolic syndrome,” Dr. Maureen Storey, senior vice president for science policy for the American Beverage Association, said. “There is a critical flaw in the design of this meta-analysis in that the authors focus solely on the impact of one calorie source – sugar-sweetened beverages – on weight, rather than looking at all sources of calories.”

Malik said the individual studies accounted for known differences between the two groups of people that might explain the different rates of type 2 diabetes and metabolic syndrome.

“Sure, people who drink soda tend to be less physically active, they might eat more saturated fat,” she said. But even after the researchers accounted for weight differences, the association between sweetened drinks and diabetes persisted, she said.

Dr. Grout’s comment:

Liquid sugar, as these beverages are often called, causes blood sugar levels to rollercoaster with quick spikes and rapid falls. If for years you eat more sugar than is needed by the muscles for exercise, you strain the pancreas, asking it to make excess insulin constantly to lower your blood sugar level. When the pancreas starts to lose control – you have a fasting blood sugar levels of 110 mg/dL or greater – you have metabolic syndrome. Eventually, the pancreas cannot make enough insulin, and the blood sugar level remains chronically high – a fasting blood glucose level of 126 mg/dl or higher. At this point, the patient is diagnosed with diabetes.

The researchers are not saying sugary drinks are the only factor associated with diabetes, but it’s one that can really make an impact if it’s reduced.