The terms “micro” and “biome” are derived from Ancient Greek, where “micro” means small and “biome” means life (Berg et al., 2020). The microbiome refers to microorganisms, their genes, and the surrounding environmental conditions (e.g., pH, oxygen and substrate availability, and moisture level) (Marchesi & Ravel, 2015). Module 2 of NP 120 Part I introduces the microbiome in great detail.

Microbiota refers to all of the microorganisms (e.g., bacteria, viruses, and fungi) found in a specific environment, and its diversity (i.e., variety) differs from person to person (Ursell et al., 2012; Marchesi & Ravel, 2015). In this course, we will focus on the microbiota (primarily bacteria) that live in the large intestine of the GIT.

The microbiota-gut-brain axis (MGBA) is a network of interconnected biological systems that facilitates bidirectional communication between the GIT and the brain (Morais et al., 2020). MGBA is essential for maintaining gastrointestinal and microbial ecosystem homeostasis and causing physiological changes in the brain that influence mood and behavior (Morais et al., 2020; Generoso et al., 2021),.

The network of interconnected biological systems within the body that facilitate the bidirectional communication between the gastrointestinal tract and the brain influences all elements of the Diet-mental health relationship (DMHR) within nutritional psychology, including the psychological, behavioral, cognitive, interoceptive, sensory-perceptual, and psychosocial elements.

Microbiota-derived metabolites are the byproducts of gut microbiota that act as signaling molecules and are released during the digestion and fermentation of non-absorbable and non-digestible dietary fibers, e.g., SCFAs.

The microbiota-gut-brain axis (MGBA) is a complex bidirectional communication network involving neural, immune, and biochemical pathways connecting the gut microbiota to the brain. It significantly influences our physiological state and mental well-being.

A bidirectional communication network linking the gut microbiota, gastrointestinal system, and central nervous system through neural, endocrine, immune, and metabolic pathways. This axis influences mood, cognition, behavior, and appetite regulation.

Microglia are specialized immune cells in the central nervous system (CNS) that function as the primary resident macrophages. They play a crucial role in immune defense in the brain and maintain tissue homeostasis.

Micronutrients are essential nutrients that the body needs in smaller quantities than macronutrients (i.e., carbohydrates, proteins, and fats). These include vitamins and minerals crucial for various physiological functions, including metabolism, growth, and overall health.

Mindful eating is an approach to food consumption that involves paying full attention to the sensory experience of eating and being present in the moment without judgment. It emphasizes awareness of hunger and satiety cues, the taste and texture of food, and the overall eating experience.