Sugary drinks linked to type 2 diabetes regardless of obesity: Meta analysis
Reviewing 17 independent studies, researchers led by Fumiaki Imamura from the University of Cambridge, estimated that a daily serving of one sugar-sweetened beverage was associated with an 18% increase in diabetes. This fell to 13% once obesity, a possible confounding factor, had been taken into account.
For artificially sweetened beverages they calculated an 8% increase and 7% for fruit juice. Although admitting the findings for artificially-sweetened rinks and fruit juice may be weak due to publication bias, the researchers nonetheless said there was little evidence for the benefits of these drinks as healthy alternatives.
“Our findings have strong public health implications, they wrote. “Despite the limitations of this review, the current consumption of sugar sweetened beverages was estimated to cause approximately two million excess events of type 2 diabetes in the USA and 80 000 in the UK over 10 years. This could cost nearly £12.0bn in the USA and £206m in the UK.”
The authors admitted their findings were limited by the observational nature of the studies under review, ruling out any definite causal conclusions.
'No strong evidence'
The findings, published in the British Medical Journal, have also been questioned by other scientists.
Dr Alasdair Rankin, director of research at Diabetes UK, said that while the study added to evidence that sugary drinks were bad for health and could increase the risk of type 2 diabetes, it did not provide strong evidence about whether this was because of the calories they contained or because of “something else going on in the body that was leading to an increase in risk.”
Tom Sanders, professor emeritus of nutrition and dietetics at King’s College London, said the findings – based on soft drink consumption in the years preceding a diabetes diagnosis – did not prove a causal effect because people tend to drink more in the early stages of type 2 diabetes.
“It is important to stress that this study does not prove a cause-effect relationship and there are no trials as yet showing that reducing sugar sweetened beverages decreases the incidence of type 2 diabetes."
The main risk factors remained age, obesity and physical inactivity, he said.
Nonetheless, Kawther Hashem, nutritionist at Action on Sugar said that this study added to the increasing evidence of the alarming impact of sugary drinks on public health.
“It’s therefore imperative that reformulation, a duty on sugary drinks and protecting children from the industry's aggressive marketing of such products are key components of David Cameron’s obesity strategy,” she said.
The findings come as the UK government’s SACN report ditched a 10% upper limit on free sugar intake last week, instead recommending that people get no more than 5% of daily energy from free sugars.
Source: British Medical Journal
Published online 21 July 2015, doi: 10.1136/bmj.h3576
“Consumption of sugar sweetened beverages, artificially sweetened beverages, and fruit juice and incidence of type 2 diabetes: systematic review, meta-analysis, and estimation of population attributable fraction”
Authors: Fumiaki Imamura et al.