Effect of Monosodium Glutamate on Body Weight and Alanine Aminotransferase Activity in Wistar Rats

Background: In recent days, the use of seasonings to enhance the flavor of food has been increased. A variety of seasonings are produced now days and the constituents of these flavor-enhancers are unknown to ignorant consumers. The consumers were preferred to eat food with good taste without consideration the effect of additives on their health. These seasonings contain monosodium glutamate (MSG) which really spiced the food.

Aim: This study sought to investigate the effect of MSG on body weight and alanine aminotransferase activity.

Place and Duration: This research was carried out at the Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, Abia State University, Uturu, and the Department of Chemical Pathology, St. Anthony’s Hospital Ltd. Aba, both in Abia State, Nigeria in 2011.

Methods: MSG (3g/satchet containing 99% MSG) was obtained from a Grocery Store at New Market, Aba in Abia State, Nigeria. Forty Wistar rats were used for this study. Fifteen of the rats were used for acute toxicity test (LD50) and twenty-five for the experiment. The 25 Wistar rats were divided into five groups of 5 rats each. Animals in groups A, B, C, and D were respectively administered 500 mg/kg, 750 mg/kg, 1000 mg/kg and 1,250 mg/kg of MSG thoroughly mixed with standard feed for eight weeks. Animals in group E received equal amount of feeds without MSG added. This group served as the control group. At the end of 8 weeks, animals were fasted overnight and anaesthetized using diethyl ether. Blood samples were collected by cardiac puncture and ALT activity was determined using standard method.

Result: The LD50 was taken to be 500 mg/kg, which is the median of 200 mg/kg which did not kill any of the animals and 800 mg/kg that killed all its animals. MSG was observed to increase weight gain as well as ALT activity when compared with control animals.

Conclusion: The elevation of ALT activity by MSG is an indication that it can induce hepatotoxicity.