Tuesday Dec 9, 2013 (foodconsumer.org) --Aspartame controversy again.  A new study in Drug and Chemical Toxicology suggests that high intake of an artificial sweetener that is commonly used in diet soda can cause antioxidant imbalance in the brain and mild vascular congestion.

R. Harikumaran Nair, School of Biosciences, Mahatma Gandhi University in Kottayam, India and colleagues conducted the study and found rats fed aspartame daily in a dose of 1000 mg per kg body weight for 180 days lowered reduced glutathione (GSH) and the activity of glutathione reductase in their brains while daily ingestion of aspartame in a dose of 500 mg/kg only significantly reduced GSH concentration.

Reduced glutathione and glutathione reductase are important for reducing oxidative stress, which is believed to be associated with a myriad of chronic diseases.

The study also found daily ingestion of aspartame in a dose of 1,000 mg/kg bw caused mild vascular congestion.

The study concluded "The results of this experiment indicate that long-term consumption of aspartame leads to an imbalance in the antioxidant/pro-oxidant status in the brain, mainly through the mechanism involving the glutathione-dependent system."

 In the United States, one can of diet soda (355 ml) contains 180 mg of aspartame.    And the Food and Drug Administration allows daily intake of 50 mg of aspartame per kg body weight for adults.  This means an adult would need to drink 21 cans to surpass the FDA's ADI. 

The study suggests that an adult with 75 kg body weight would need to drink 417 cans of diet soda to have the negative effect on the antioxidant status and vascular congestion.

Early long term studies found long term consumption of aspartame was associated with cancer development.  But short term studies did not find the association.  Also the industry says that the dose of aspartame used to generate the side effects was much higher than what people can ingest through their foods and beverages. (David Liu)