Effect of aspartame on lipid peroxidation and membrane bound enzymes in immune organs of rats

Abstract

Objective: The artificial dipeptide sweetener aspartame (L-aspartyl-L-phenylalanine methyl ester) is present in many products especially unsweetened and sugar products. These products are frequently utilized by people trying to lose weight or patients with diabetes. Concern relating to the possible adverse effect has been raised due to aspartame’s metabolic components. Aspartame is rapidly and completely metabolized in humans and experimental animals to aspartic acid (40%), phenylalanine (50%) and methanol (10%). Methanol, a toxic metabolite, is primarily, metabolized by oxidation to formaldehyde and then to formate: these processes are accompanied by the formation of superoxide anion and hydrogen peroxide. Methods: This study focus is to understand whether the oral administration of aspartame (40 mg/kg body weight) for 90 days has any effect on lipid peroxidation, nitric oxide level, membrane bound ATPases of immune organs and differential leucocyte count of rats. Results: After 90 days of aspartame administration, there was a neutrophil and lymphocyte imbalance in normal white blood cell homeostasis, a significant increase in lipid peroxidation with nitric oxide level, and an alteration of membrane bound ATPase activities, which finally decreased the cellularity (reduction in organ weight and cell count) of immune organs. Conclusion: Aspartame metabolite methanol or formaldehyde may be the causative factors behind the changes observed. This study concludes that oral administration of aspartame for longer duration may cause oxidative stress on immune organs.