The Hindu
28 October 2010
New Delhi, India

Consumption of one–two sugary beverages like soft drinks and iced teas per day increases the risk of type 2 diabetes by 26 per cent besides putting people at a "consistently greater risk" of high blood pressure, according to a study by Harvard researchers.

Researchers at Harvard School of Public Health (HSPH) compared people who drank one to two sweetened soft drinks, fruit drinks, iced tea, energy drinks or vitamin water every day with people who had one or no sweetened beverage over the course of a month to see which group was more likely to develop type 2 diabetes or metabolic syndrome.

Metabolic syndrome is a group of risk factors, such as high blood pressure and excess body fat around the waist, that increase the risk of coronary artery disease, stroke and diabetes.

The findings showed that people who drank one to two sugary drinks per day had a 26 per cent higher risk of developing type 2 diabetes and a 20 per cent higher risk of developing metabolic syndrome as compared to those who consumed less than one sugary drink per month.

Drinking one 12–ounce (340 grams) serving per day increased the risk of type 2 diabetes by about 15 per cent.

"Many previous studies have examined the relationship between sugar–sweetened beverages and risk of diabetes and most have found positive associations but our study, which is a pooled analysis of the available studies, provides an overall picture of the magnitude of risk and the consistency of the evidence," the study’s lead author and a research fellow in the HSPH Department of Nutrition Vasanti Malik said.

The researchers, led by Ms. Malik, did a meta–analysis that pooled 11 studies that examined the association between sugar–sweetened beverages and risk of diabetes and metabolic syndrome.

The studies included more than 300,000 participants.

After follow–up ranging from four to 20 years, 15,043 people were diagnosed with type 2 diabetes and 5,803 had metabolic syndrome.

While a number of factors are at work in the development of type 2 diabetes and metabolic syndrome, sugar–sweetened beverages represent one "easily modifiable" risk factor that if reduced will likely make an important impact, the study said.

"People should limit how much sugar–sweetened beverages they drink and replace them with healthy alternatives, such as water, to reduce risk of diabetes as well as obesity, gout, tooth decay and cardiovascular disease," Ms. Malik said.

Consumption of sugary drinks, the majority of which are sodas, has increased substantially in the US and across the globe.

Previous scientific studies have shown consistent associations with weight gain and risk of obesity.

"The association that we observed between soda consumption and risk of diabetes is likely a cause–and–effect relationship because other studies have documented that sugary beverages cause weight gain, and weight gain is closely linked to the development of type 2 diabetes," senior author and professor of nutrition and epidemiology at HSPH, Frank Hu said.