Aspartame, tobacco, alcohol, and caffeine as predictors of age-related memory decline

Abstract

The food additive aspartame, commonly known by its trademark name NutraSweet, is used worldwide in over 6000 food and beverages. Since its release, the long-term cognitive effects of NutraSweet have been studied in adults and children. The present study examined the relationships among self-reported aspartame use, short-term memory performance, and self-perceived memory in an elderly population. In addition, the interactions among aspartame and several other dietary/lifestyle factors including tobacco, alcohol, and caffeine were examined. Sixty-nine elderly subjects (mean age of 74.6 years) completed a dietary questionnaire, a battery of short-term memory tests, and the Everyday Memory Questionnaire (EMQ). The multiple regression results determined that overall, age, education, and gender were the best predictors of scores on the short-term memory tests. Years of aspartame use was a significant predictor of scores on the Memory for Four Words test, and individuals who reported using aspartame over many years received higher scores on this delayed verbal recall test. Years of caffeine use were associated with improvements in the Paired-Learned Associates test. The MANCOVA results found a significant main effect for aspartame use. Follow-up analyses determined present aspartame use was associated with improvements in delayed verbal recall and individuals who reported never using aspartame showed worse self-reported memory on the EMQ. No other group differences for nicotine, alcohol, or caffeine, or interactions among the products, were significant. Although normal aging typically worsens memory in most individuals, the influence of long-term aspartame use might have altered the rate of memory decline. The present experiment suggests that aspartame does not impair short-term memory, and may even enhance memory on certain tasks. With further research, the relationship between long-term aspartame use and memory performance in the elderly will be established and the safety of aspartame will be confirmed.