Bacteria

Bacteria are a type of microorganism with different shapes and structures. In bacteriology, they are mainly classified into two main types, gram-negative and gram-positive, based on the physical and chemical properties of the cell wall.

Many bacteria live naturally in and on the human body, with the gastrointestinal tract containing a particularly diverse microbial community. These microorganisms can interact with dietary components and contribute to processes such as nutrient metabolism, fermentation, and the production of certain microbial metabolites. The composition and activity of gut bacteria can vary according to diet, lifestyle, medications, and other factors, making the microbiome an important area of nutritional research.

From a nutritional psychology perspective, gut bacteria are relevant to the gut-brain axis, a network of communication involving the gastrointestinal tract, nervous system, immune system, and microbial environment. Research is examining how microbial activity may relate to mood, stress responses, and cognitive processes. However, these relationships are complex, and individual bacterial species or dietary changes should not be assumed to directly cause specific mental health outcomes.