One type of bacteria commonly found in a healthy gut microbiome is Bacteroidetes. Other common phyla include Firmicutes, Actinobacteria, Proteobacteria, and Verrucomicrobia. These bacteria play important roles in extracting nutrients from food, synthesizing vitamins and amino acids, maintaining homeostasis, and protecting against pathogens. A high-fiber diet, including fruits, vegetables, and cruciferous vegetables, is positively correlated with increased diversity of bacteria in the microbiome.