Soft drink with ice

Drinking water or unsweetened tea or coffee in place of one sugary drink per day can reduce the risk of type 2 diabetes, according to research published today in the journal Diabetologia.

Our study adds further important evidence to the recommendation from the World Health Organization to limit the intake of free sugars in our diet

Nita Forouhi

The study indicates that for each 5% increase of a person’s total energy intake provided by sweet drinks including soft drinks, the risk of developing type 2 diabetes may increase by as much as 18%.

The research is based on the EPIC-Norfolk study, which included more than 25,000 men and women aged 40–79 years living in Norfolk, UK. Study participants recorded everything that they ate and drank for seven consecutive days covering weekdays and weekend days, with particular attention to type, amount and frequency of consumption, and whether sugar was added by the participants. During approximately 11 years of follow-up, 847 study participants were diagnosed with new-onset type 2 diabetes.

Dr Nita Forouhi, of the Medical Research Council (MRC) Epidemiology Unit, University of Cambridge, who led the study, says: “By using this detailed dietary assessment with a food diary, we were able to study several different types of sugary beverages as well as artificially sweetened beverages – such as diet soft drinks – and fruit juice, and to examine what would happen if water, unsweetened tea or coffee or artificially sweetened beverages were substituted for sugary drinks.”

In an analysis that accounted for a range of important factors including total energy intake, the researchers found that there was an approximately 22% increased risk of developing type 2 diabetes per extra serving per day habitually of each of soft drinks, sweetened milk beverages and artificially sweetened beverages consumed, but that consumption of fruit juice and sweetened tea or coffee was not related to diabetes. After further accounting for body mass index and waist girth as markers of obesity, there remained a higher risk of diabetes associated with consumption of both soft drinks and sweetened milk drinks, but the link with artificially sweetened beverages consumption no longer remained, likely explained by their greater consumption by those who were already overweight or obese.

This new research adds to previous research published in Diabetologia, which collected information from food frequency questionnaires across eight European countries. That previous work indicated that habitual daily consumption of sugar sweetened beverages was linked with higher risk of type 2 diabetes, consistent with the current new findings.

In the new study, the authors also found that if study participants had replaced a habitual daily serving of soft drinks with a serving of water or unsweetened tea or coffee, the risk of diabetes could have been cut by 14%, and by replacing a habitual serving of sweetened milk beverage with water or unsweetened tea or coffee, that reduction could have been 20%–25%. However, consuming artificially sweetened beverages instead of any sugar-sweetened drink was not associated with a statistically significant reduction in type 2 diabetes, when accounting for baseline obesity and total energy intake.

Dr Forouhi adds: “The good news is that our study provides evidence that replacing a habitual daily serving of a sugary soft drink or sugary milk drink with water or unsweetened tea or coffee can help to cut the risk of diabetes, offering practical suggestions for healthy alternative drinks for the prevention of diabetes. This adds further important evidence to the recommendation from the World Health Organization to limit the intake of free sugars in our diet.”

The authors acknowledge limitations of dietary research which relies on asking people what they eat, but their sample size was large with long follow-up and had detailed assessment of diet that was collected in real-time as people consumed the food/drinks, rather than relying on memory.

The research was supported by the Medical Research Council and Cancer Research UK.

Adapted from a press release from Diabetologia.

O’Connor, L et al. Prospective associations and population impact of sweet beverage intake and type 2 diabetes, and effects of substitutions with alternative beverages. Diabetologia; 30 April 2015


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