Aspartame may block the activity of an enzyme (IAP) produced in the small intestine.
Sarah Shireen Gul, A. Rebecca L. Hamilton, Alexander R Munoz, Tanit Phupitakphol, Liu Wei, Sanjiv K Hyoju, Konstantinos P Economopoulos, Sara Morrison, Dong Hu, Weifeng Zhang, Mohammad Hadi Gharedaghi, Haizhong Huo, Sulaiman R Hamarneh, Richard A. Hodin. Inhibition of the gut enzyme intestinal alkaline phosphatase may explain how aspartame promotes glucose intolerance and obesity in mice. Applied Physiology, Nutrition, and Metabolism, 2016; DOI: 10.1139/apnm-2016-0346
