Chronic exposure to food additives: Monosodium glutamate and tartrazine dysregulate gut-brain axis in zebrafish model

The commonly used food additives to enhance color and flavor are Monosodium glutamate and Tartrazine. The effects of both were investigated on chronic exposure of over 30 days to adult zebrafish, in four groups: control, tartazine (31,844 ppm), monosodium glutamate (10.9 × 10³ ppm), and a combined exposure group (monosodium glutamate+tartazine = 5450 ppm + 15,922 ppm), with 10 fish per group in triplicates. Neurobehavioral tests, acetylcholinesterase (AChE) activity, metabolic enzyme assays, and quantification of serotonin and cortisol levels were performed. DNA was extracted from zebrafish gut samples for gut microbiota analysis. Zebrafish exposed to monosodium glutamate and tartazine showed a statistically significant reduction in social interaction, mirror biting, and preference for familiar and novel objects. The combined exposure group showed increased anxiety, spent more time in light zones, and increased transition movements. Tartazine exposure elevated AChE activity and serotonin levels, and monosodium glutamate exposure increased cortisol. Disruptions in cortisol and serotonin levels, with increased AChE activity, were linked to stress, mood swings, memory deficits, and cognitive impairment. Gut microbiota analysis revealed a higher abundance of Actinobacteria, and increased Enterobacter indicates inflammation in the gut of treatment groups. Chronic consumption of monosodium glutamate and tartazine may disrupt metabolic processes, induce obesity, and impair cognitive functions, indicating potential health risks associated with these additives.