No Effect of Sugar Sweetened or Diet Beverages on Performance of a Battery of Cognitive Assessment Tests

Abstract

IntroductionDietary sugar has been alleged to contribute to the obesity epidemic. As a primary source of sugar in the American diet Sugar Sweetened Beverages (SSB) have been specifically targeted for caution. It has been argued that it is not just an issue of calories or metabolic products, but also sweetness of beverages as both SSB and diet beverages which may produce changes in cerebral activity and associated cognitive impairment under experimental conditions. However, few data exists on how typical consumption of these beverages may affect cognitive function.MethodsFor six months all participants followed the ADA Exchange Diet, individually tailored according to each participant's caloric needs. Participants were required to incorporate 2 servings (12oz) per day of a Sugar Sweetened Beverage (SSB) or Diet Beverage (Diet), both caffeine free. A third group who drank only water were also included as a control. Before and after the intervention participants were assessed on a battery of tests that measure a wide variety of cognitive functions (CANTAB). The tests used were: Spatial Working Memory (SWM), Intra‐Extra Dimensional Set Shift (IED), Stop Signal Task (SST), Delayed Matching to Sample (DMS), Paired Associates Learning (PAL), and Rapid Visual Information Processing (RVP). In additional participants also performed the Iowa Gambling Test (IGT). Data presented are means ± SD.ResultsNone of the groups gained a significant amount of weight in the combined study population (161. ± 24 vs 162 ± 23.9 lbs, p=0.075), nor were there any differences among groups (interaction p=0.899). There was a decrease in the strategy score for SWM in the pooled study population (32.5 ± 5.7 vs 30.8 ± 6.5, p<0.05), yet this coincided with a decrease in SWM errors (26.0 ±20.2 vs 21.3 ± 16.0, p<0.01). RVP A’ also increased (0.90 ± 0.06 vs 0.92 ± 0.5, p<0.05). Diet showed a greater improvement in memory in PAL relative to the water group (respectively 19.9 ±3.9 vs 21.8 ± 2.8 and 21.9 ± 3.2 vs 20.0 ± 4.6, p<0.05). No other measures changed from pre to post intervention and none other than PAL Memory were affected by group assignment (p>0.05).ConclusionThese data do not support the theory that regular consumption of sweet beverages, either SSB or diet, cause cognitive changes that have previously been associated with the development of obesity.Support or Funding InformationSupported by an unrestricted grant from The Coca Cola Company