The potential influence of food additives and contaminants on the gut microbiota: A comprehensive review

Gut microbiota (GM) is a complex consortium of diverse microbes in the gastrointestinal tract, which collectively sustains host health through various physiological processes. GM's health benefits include regulation of host immunity, neurotransmitters, intestinal epithelium, energy absorption, and short-chain fatty acids (SCFAs) production. The extensive utilization of additives and the presence of contaminants in food has raised concerns regarding the GM. Chemical compounds such as pesticides, potentially toxic elements, microplastics, antibiotics, and certain food additives (e.g., emulsifiers, sweeteners, preservatives) have been shown to disrupt the GM's composition, leading to gut dysbiosis with subsequent adverse health effects. The complex mechanisms through which these substances affect microbiota lack a thorough understanding, although animal studies have provided new insights into the dysbiosis caused by these substances in the GM. This review aims to comprehensively explore the interaction of food additives and contaminants with the equilibrium of GM, with strong emphasis on their influence on gut health. We outline these substances as causing inflammation, gastrointestinal injury, altered short-chain fatty acids and polyamines' synthesis, higher expression of pro-inflammatory cytokines, and hepatic lipid metabolic disorders. Further studies are needed to understand the mechanisms and impact of such negative effects of food additives and contaminants on GM's integrity.