Sunday Feb. 15, 2015 (foodconsumer.org) -- A. K. Choudhary AK and Devi R. Sheela Devi at University of Madras in Tamilnadu, India published a study to suggest that aspartame can increase oxidative stress and alter immune functions.

Aspartame is an artificial non-caloric sweetener and has been used in diet and low calorie products and also other foods, drugs and hygiene products.  Some studies found long term consumption of high amounts of aspartame caused tumors in rodents.

Aspartame is known to be metabolized by esterases and peptidases in the gut to three chemicals, aspartic acid, and phenylalanine and methanol.  Methanol can be metabolized further to form more toxic chemical called formaldehyde. 

In the current study, Wistar Albino rats were fed either 40 mg of aspartame per kg of body weight or placebo per day for 90 days or three months.  At the end of the treatment, researchers tested a range of parameters including "corticosterone, lipid peroxidation, antioxidant activity, nitric oxide, reduced glutathione and cytokines (interleukin 2, interleukin 4, tumor necrosis factor-α and interferon-γ)."

The researchers found a significant increase in serum corticosterone, lipid peroxidation, interleukin 4, and nitric oxide concentrations and a decrease in enzymatic and non-enzymatic antioxidants and interleukin 2, tumor necrosis factor-α and interferon-γ.

The findings indicate that aspartame acts as a chemical stressor to increase corticosterone, lipid oxidation and nitric oxide and induce free radicals in the blood that explain the change in cytokines and altered immune function.

 The researchers speculate that the toxicity of aspartame may be due to the aspartame metabolite methanol or formaldehyde.  (David Liu, PHD)

Choudhary AK, Sheela Devi R.  Longer period of oral administration of aspartame on cytokine response in Wistar albino rats. Endocrinol Nutr. 2015 Feb 10.