In line with rigorous safety assessments of food additives, the effects of food additives on human physiology are thoroughly investigated. However, their effects on the gut microbiota are often overlooked. Recent studies suggest that preservatives can alter the composition of the microbiota, leading to either positive or negative immunomodulatory responses. Artificial sweeteners have been shown to inhibit the growth of beneficial gut bacteria and promote antibiotic resistance. Metallic nanoparticles used as colors can disrupt the balance of the gut microbiota by increasing pathogenic bacteria and reducing beneficial bacteria. Some emulsifiers disrupt the composition of the gut microbiota, increase intestinal permeability, and cause inflammation. This review provides an overview of the most recent work published in the past year (April 2023 to March 2024) on the effects of the most commonly used food additives on the gut microbiota.