Fang Ye

Date of Award


Document Type


Degree Name

Master of Science (MS)




The FDA estimates that 35% of Americans regularly consume aspartame, an artificial sweetener used in diet drinks and other sugar-free food items. Some anecdotal reports indicate the substance has been associated with health, behavioral, and cognitive concerns. The FDA and other regulatory agencies indicate it is safe for use up to 50mg/kg/day. They further advise individuals with metabolic phenylalanine disorders not to consume this product. This conflicting advice has caused confusion for consumers and practioners. Therefore, the purpose of this study was to examine the effects of aspartame consumption on cognitive functioning of healthy adults.

Orem's theory of Self-Care guided this descriptive, clinical study. The effect of dietary aspartame consumption on cognitive function of study participants was monitored and analyzed for participants consuming weighed food intakes for 16 days.

This study tested the hypothesis that cognitive functioning is poorer when participants' dietary intake of aspartame is higher. The sample population was comprised of 180 randomly selected ethnically-diverse 18 to 40 year old healthy adults recruited through a midwestern university. Instruments used for measurement included a Demographic Questionnaire, Weighed Food Intakes, Kearney and Fleischer's Exercise of Self-care (alpha= .80), the Sternberg Item Recognition Test (r =.95), and the Vandenberg Mental Rotation Test (KR- 20=.88).

Depending on the cognitive task (the Vandenberg Mental Rotation Test), results indicated that cognitve function was significantly better (p=.03) when participants consumed less aspartame (<1000mg/day) than those who consumed more (>1000mg/day).

The relevance of these results is that healthcare professionals need to be aware of dietary factors that can maximize cognitive function and promote quality of life for their clients.