Beyond nutrient density: linking rapid food composition assessment to human nutritional adequacy and bioavailability

Nutrient density serves as a core criterion for identifying foods supportive of healthy and sustainable dietary patterns, yet it is conventionally quantified as the concentration of a defined set of nutrients per unit energy. Nutrient-profiling models typically combine nutrients to encourage, such as protein, dietary fiber, vitamins A, C and E, calcium, iron, magnesium and potassium, with nutrients to limit, namely saturated fat, added sugars and sodium. Such concentration-based metrics offer limited insight into the critical physiological processes governing nutrient utilization, including digestive release, intestinal absorption, and tissue-level bioavailability. This limitation has grown increasingly relevant amid the diversification of food systems toward plant-based alternatives, novel foods, climate-resilient crops, and reformulated products, where measured chemical composition frequently diverges substantially from delivered nutritional value. Advanced rapid analytical platforms, which include near-infrared and mid-infrared spectroscopy, Raman spectroscopy, hyperspectral imaging, miniaturized portable devices, and machine learning-enabled prediction, now enable high-throughput, non-destructive compositional characterization with high accuracy. Untargeted metabolomics is considered alongside these platforms, although it is not rapid in the same operational sense: extraction, sample preparation, chromatographic separation and spectral annotation remain time-consuming, costly and labor-intensive relative to near-infrared or Raman measurement. However, these techniques alone do not determine biological availability, which is modulated by food matrix structure, processing history, nutrient–nutrient and nutrient–antinutrient interactions, digestion kinetics, and interindividual physiological variation. This review frames rapid compositional assessment as an entry point rather than a definitive endpoint of nutritional evaluation, proposing an integrated continuum spanning measured composition, matrix characterization, in vitro digestion, bioaccessibility, bioavailability, dietary contribution, and overall nutritional adequacy. Key nutrient classes, including proteins and indispensable amino acids, minerals, vitamins, lipids, carbohydrates and dietary fiber, and bioactive compounds, are evaluated across each stage of this continuum, with emphasis on conditions under which rapid analytical methods reliably predict physiological outcomes. The review further explores the integration of compositional data with bioavailability estimates in nutrition surveillance, food product formulation, and food system policy, and outlines essential validation requirements relative to human nutritional outcome data.