Monosodium Glutamate Induces Changes in Hepatic and Renal Metabolic Profiles and Gut Microbiome of Wistar Rats

Abstract

The short- and long-term consumption of monosodium glutamate (MSG) increases urinary pH but the effects on the metabolic pathways in the liver, kidney and the gut microbiota remain unknown. To address this issue, we investigated adult male Wistar rats allocated to receive drinking water with or without 1 g% MSG for 2 weeks (n = 10, each). We performed a Nuclear Magnetic Resonance (NMR) spectroscopy-based metabolomic study of the jejunum, liver, and kidneys, while faecal samples were collected for bacterial DNA extraction to investigate the gut microbiota using 16S rRNA gene sequencing. We observed significant changes in the liver of MSG-treated rats compared to controls in the levels of glucose, pyridoxine, leucine, isoleucine, valine, alanine, kynurenate, and nicotinamide. Among kidney metabolites, the level of trimethylamine (TMA) was increased, and pyridoxine was decreased after MSG-treatment. Sequencing of the 16S rRNA gene revealed that MSG-treated rats had increased Firmicutes, the gut bacteria associated with TMA metabolism, along with decreased Bifidobacterium species. Our data support the impact of MSG consumption on liver and kidney metabolism. Based on the gut microbiome changes, we speculate that TMA and its metabolites such as trimethylamine-N-oxide (TMAO) may be mediators of the effects of MSG on the kidney health.

Evaluation of morphological changes of the pancreas in the conditions of experimental action of sodium glutamate

“…In our study, with increasing duration of the experimental period, we observed progressive edema, replacement of pancreatic parenchyma with connective and adipose tissues, and deviations in the histological structure of the acini in the pancreatic gland. Our findings are consistent with other studies where obesity in animals was induced by high-fat diets, resulting in pancreatic steatosis, inflammation, and fibrosis [1,7,9,10]. Thus, the experimental modeling of sodium glutamate and subsequent investigation of the structure of the pancreatic gland allowed us to identify the main pathomorphological changes.…”

Beyond Plants: The Ultra-Processing of Global Diets Is Harming the Health of People, Places, and Planet

“…Although less attention has been paid to the dietary additives captured in the NOVA classification, volumes of pre-clinical research have linked the non-nutritive components of foods (e.g., emulsifiers, flavor enhancers, and artificial colors) to non-communicable diseases, including gastrointestinal and mental disorders [143][144][145][146][147][148][149][150]. In animal models, various dietary additives, including emulsifiers and monosodium glutamate (MSG), have been shown to alter the gastrointestinal microbiome [151][152][153][154]; ultra-processed food-induced alterations to the gut microbiome might account for many of the diet's health-related consequences [155] (Figure 2). Indeed, compared to either MSG or a high-fat diet alone, the combination of MSG and a high-fat diet (i.e., characteristic of ultra-processed foods) has been noted to cause a shift in gut microbiota reflective of an obesity signature [156].…”

Salt reduction in bakery products: A critical review on the worldwide scenario, its impacts and different strategies

“…Some taste enhancers are chemical substances, such as monosodium glutamate (MSG) and hydrolyzed protein (Israr et al, 2016). Since the use of monosodium glutamate is controversial for its potential toxicity (Nahok et al, 2021) and more studies are needed to elucidate its effects on the human organism, this review will focus on clean label alternatives.…”