bodymetabolizable

Bodymetabolizable is a term used to describe the portion of a substance that the body can metabolize to yield energy or synthesize tissues, after digestion and absorption. It is a concept used in nutrition science to distinguish the metabolizable fraction from the total or gross content of a compound. In practice, researchers typically discuss metabolizable energy (ME) or metabolizable protein (MP), while “bodymetabolizable” may be used informally to indicate the biologically usable portion of a nutrient.

The concept depends on several steps: digestion in the gastrointestinal tract, absorption of digestion products into the bloodstream, and cellular metabolism. Substances with high metabolizability contribute measurable energy or essential nutrients, whereas components that resist digestion, are not absorbed, or are excreted without metabolism are less bodymetabolizable.

Measurement methods include controlled feeding trials that compare gross energy intake with losses in feces and urine to estimate metabolizable energy, or analyses of amino acid digestibility and absorption for MP. In human nutrition, ME is less commonly reported; instead, net energy and digestible energy may be used. In some animals, the productive use of metabolites is tracked with balance studies or isotopic tracers.

Factors influencing bodymetabolizable fraction include chemical form (e.g., starch versus resistant starch), degree of processing, presence of anti-nutrients, gut microbiota composition, health status, and the body’s metabolic state. The term is less standardized than ME or MP, and its precise meaning may vary by context.

Use of the term is mainly theoretical or informal. When precision is required, scientists prefer established metrics such as metabolizable energy, digestible energy, digestibility, or metabolizable protein to convey the usable portion of nutrients.