An odor one is not consciously aware of.

Amino acids are the basic building blocks of proteins, consisting of a central carbon atom bonded to an amino group (-NH2), a carboxyl group (-COOH), and a unique side chain (R group) that distinguishes one amino acid from another. They play crucial roles in various biological processes, including protein synthesis, enzyme function, and as precursors to neurotransmitters and other essential molecules in the body.

The amygdala is a small, almond-shaped region deep within the brain that plays a central role in processing emotions, particularly fear and anxiety. It also contributes to assessing the emotional significance of experiences, including those related to food and dietary choices.

Anhedonia is the inability to experience pleasure from usually pleasurable situations, and it is a primary symptom of depression, schizophrenia, and other mental disorders (Sharma et al., 2004).

Anorexia nervosa is an eating disorder characterized by self-imposed restriction of energy intake, leading to a significantly low body weight. Individuals with anorexia have an intense fear of gaining weight and exhibit a distorted perception of body image, often failing to recognize the severity of their low weight. This disorder can result in serious physical and psychological health complications, requiring a multidisciplinary approach to treatment, including nutritional support and psychotherapy.

The anorexigenic peptides are derived from the Greek words ἀν- (an-, “without”) and ὄρεξις (órexis, “appetite”), meaning “without appetite.” They are primarily produced in the stomach to suppress appetite and food intake (Sobrino Crespo et al., 2014).

The term “anorexigenic” is derived from the Greek words ἀν- (an-, “without”) and ὄρεξις (órexis, “appetite”), meaning “without appetite” and referring to “appetite-suppressing” hormones produced to suppress appetite and reduce food intake, such as GLP-1, CCK, and PYY (Sobrino Crespo et al., 2014).

The absence or failure of ovulation during a menstrual cycle resulting in the lack of egg release from the ovaries. It can result from hormonal imbalances, stress, excessive exercise, certain medical conditions, or life stages such as menopause, and is a common cause of infertility.

A region of the brain located in the medial prefrontal cortex, the ACC plays a key role in detecting cognitive conflict and errors, regulating emotional responses, monitoring ongoing performance, and signaling the need for increased cognitive control.

Antibiotic-induced microbiota depletion (AIMD) refers to the administration of one or more antibiotics that deplete the microbiota and disrupt the microbial balance, including richness and diversity. This can harm host health by increasing susceptibility to pathogen infection (Modi et al., 2014). This procedure is often used to investigate the role of gut microbiota in some pathological conditions (Patangia et al., 2022).