The memorandum released in 1997 points to a significant problem with aspartame consumption. Yet, the FDA considers this a safe product for human consumption.
The Departments of Toxicology and Narcotics, and Medical Biochemistry, National Research Centre in Egypt released their dose dependent aspartame research in December of 2012. The study suggests that repeated aspartme administration resulted in impaired memory performance and increased brain oxidative stress.
Abdel-Salam OM, Salem NA, El-Shamarka ME, Hussein JS, Ahmed NA, El-Nagar ME. Eur Rev Med Pharmacol Sci. 2012 Dec;16(15):2092-101. Studies on the effects of aspartame on memory and oxidative stress in brain of mice.