Interactive effects of neonatal exposure to monosodium glutamate and aspartame on glucose homeostasis

Abstract

BackgroundRecent evidence suggests that the effects of certain food additives may be synergistic or additive. Aspartame (ASP) and Monosodium Glutamate (MSG) are ubiquitous food additives with a common moiety: both contain acidic amino acids which can act as neurotransmitters, interacting with NMDA receptors concentrated in areas of the Central Nervous System regulating energy expenditure and conservation. MSG has been shown to promote a neuroendocrine dysfunction when large quantities are administered to mammals during the neonatal period. ASP is a low-calorie dipeptide sweetener found in a wide variety of diet beverages and foods. However, recent reports suggest that ASP may promote weight gain and hyperglycemia in a zebrafish nutritional model.MethodsWe investigated the effects of ASP, MSG or a combination of both on glucose and insulin homeostasis, weight change and adiposity, in C57BL/6 J mice chronically exposed to these food additives commencing in-utero, compared to an additive-free diet. Pearson correlation analysis was used to investigate the associations between body characteristics and variables in glucose and insulin homeostasis.ResultsASP alone (50 mg/Kgbw/day) caused an increase in fasting blood glucose of 1.6-fold, together with reduced insulin sensitivity during an Insulin Tolerance Test (ITT) P < 0.05. Conversely MSG alone decreased blood triglyceride and total cholesterol (T-CHOL) levels. The combination of MSG (120 mg/Kgbw/day) and ASP elevated body weight, and caused a further increase in fasting blood glucose of 2.3-fold compared to Controls (prediabetic levels); together with evidence of insulin resistance during the ITT (P < 0.05). T-CHOL levels were reduced in both ASP-containing diets in both genders. Further analysis showed a strong correlation between body weight at 6 weeks, and body weight and fasting blood glucose levels at 17 weeks, suggesting that early body weight may be a predictor of glucose homeostasis in later life.ConclusionsAspartame exposure may promote hyperglycemia and insulin intolerance. MSG may interact with aspartame to further impair glucose homeostasis. This is the first study to ascertain the hyperglycemic effects of chronic exposure to a combination of these commonly consumed food additives; however these observations are limited to a C57BL/6 J mouse model. Caution should be applied in extrapolating these findings to other species.

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“…An increment in the body weight, transitory increases in the blood pressure and in plasma values of glucose and triglycerides alongside a transitory reduction in plasma urea was also reported after aspartame consumption [8]. Alteration of Glucose homeostasis by aspartame ingestion was also well documented a decade before [25]. Aspartame had the capacity to alter the normal antioxidant enzyme pool in many organs like liver and kidney [30].…”

“…Reduction in mean placental and maternal-fetal weights, in umbilical cord length and kariometric parameters in fetal hepatocyte nuclei majority of kariometric parameters of the hepatocytes were also well documented after aspartame treatment in rats [6]. In utero exposure of aspartame may affect spatial cognition and glucose homeostasis in mice, particularly in males [25]. An increment in the body weight, transitory increases in the blood pressure and in plasma values of glucose and triglycerides alongside a transitory reduction in plasma urea was also reported after aspartame consumption [8].…”

“…Aspartame was found to have association with the progression of many clinical disorders including hepatotoxicity, nephrotoxicity, neurotransmitter imbalance, and cognitive abnormalities. It was observed that males were more susceptible than females in many cases [25][26][27][28]. High level of the naturally occurring essential amino acid phenylalanine is a health hazard to those born with phenylketonuria (PKU) a rare inherited disease.…”

Aspartame: Effects and Awareness

“…It was observed that males were more susceptible than females in many cases. [25][26][27][28] High level of the naturally occurring essential amino acid phenylalanine is a health hazard to those born with phenylketonuria (PKU) a rare inherited disease. So the patients of phenylketonuria should not consume aspartame.…”

“…6 In utero exposure of aspartame may affect spatial cognition and glucose homeostasis in mice, particularly in males. 25 An increment in the body weight, transitory increases in the blood pressure and in plasma values of glucose and triglycerides alongside a transitory reduction in plasma urea was also reported after aspartame consumption.…”