It is well established that consumption of soft drinks containing sugar increases future risk of obesity, metabolic syndrome and type 2 diabetes. This is concerning because in the United States between 1997 and 2001 consumption of soft drinks increased by 135% and by 2004 represented 7% of total energy intake. These changes parallel the increase in cases of obesity and type 2 diabetes. Interestingly, some evidence also suggests that sugar free artificially sweetened soft drinks are associated with increased risk of type 2 diabetes. The recommendation to replace sugar containing foods with sugar free alternatives may therefore need to be further assessed. The risk of type 2 diabetes with consumption of sugar sweetened soft drinks is thought to increase due to the fructose and sucrose content, but it is unclear why sugar free versions would have a similar effect if they are devoid of these sugars.
The association between soft drink consumption and type 2 diabetes has been investigated by researchers1 in a prospective study of 40 389 healthy men. Researchers analysed intakes of both sugar free and sugar sweetened beverages from food-frequency questionnaires and tested association with type 2 diabetes. In the 20 year follow-up there were 2680 case of diabetes and after adjustment for age comparison of the top quintile with the bottom quintile for sugar sweetened beverages produced a hazard ratio of 1.25. This ratio remained relatively unchanged even after adjustment for other know risk factors for diabetes. In addition, intake of artificially sweetened soft drink was associated with an increased risk of type 2 diabetes with a hazard ratio of 1.91 between the top and bottom intake quintiles. However, adjustments for other know risk factors in the multivariate analysis removed the significance of the results.
Interestingly, the authors reported that replacement of one serving of sugar sweetened beverage with a cup of coffee (≈237mL) was able to reduce the risk of developing type 2 diabetes by 17%. In fact coffee consumption as a whole was inversely associated with type 2 diabetes, as has been reported previously. The risk of diabetes increased with consumption of artificially sweetened beverages before multivariate analysis. It is known that artificially sweetened foods stimulate appetite and it is possible that consumption increased energy intake as a whole. However, it is more likely that individuals consuming artificially sweetened beverages had a greater chance of already being overweight and at risk of developing diabetes, and were consuming the drinks in order to control weight. The underlying health of the individuals may therefore be the confounding variable. Adjustment for established risk factors in multivariate analysis removing the significance of the association supports this viewpoint.
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