Enteral formulations: Nutritional contribution, bioavailability, and implications for human health

Enteral formulas are essential nutritional source for individuals unable to receive oral nutrition, playing a critical role in the prevention of malnutrition. In this study, renal, diabetic, healing, pediatric, high-calorie, and standard formulations - with and without fiber - were evaluated. The inorganic profile (Al, As, Ca, Cd, Cr, Cu, Fe, K, Mn, Na, P, Pb, and Zn) was determined by inductively coupled plasma optical emission spectrometry (ICP OES) and graphite furnace atomic absorption spectrometry (GFAAS). The element's bioaccessibility was assessed by applying the standardized INFOGEST 2.0 in vitro digestion protocol, and the bioavailability was evaluated by the Caco-2 cell model. Bioaccessibility values (% w/w) were higher for Cu (64-107), P (60-109), and Al (43-101), intermediate for Ca (38-76), Fe (30-93), and Mn (34-95), and lower for Cr (1-41), K (29-57), and Zn (13-58). Bioavailability (% w/w) revealed limited transport for Fe (3-19) and Mn (6-14), whereas Cu, P, and Zn showed higher absorption ranges (13-30, 24-40, and 18-29). Pediatric formulas exhibited the highest Fe and Mn bioavailability, whereas diabetic formulas presented the lowest values. Toxic elements (As, Cd, and Pb) remained below the limit of detection in all studied samples. This study shows that elements delivery from enteral formulas is strongly matrix-dependent and cannot be inferred from only total elemental content. The combined evaluation of bioaccessibility and Caco-2 bioavailability provides new insights into their effective nutritional contribution and supports evidence-based formulation strategies.