Iron bioaccessibility in raw and cooked foods in vitro using fecal inocula from children and adults

Iron (Fe) is essential for human health but may induce dysbiosis and inflammation when unabsorbed. This study assessed the impact of culinary techniques on Fe bioaccessibility (FeBA) using an in vitro digestion/fermentation model with fecal inocula from children and adults. FeBA in the small intestine was significantly lower in plant-based (12.2 ± 9.91 %; 1.05 ± 0.85 mg/kg) than in animal-based foods (16.8 ± 11.7 %; 1.25 ± 0.86 mg/kg) (p < 0.0001). Cooking methods such as grilling, frying, and roasting enhanced FeBA in plant foods, likely due to Maillard reaction products. In allergic children, FeBA in the large intestine (1.77 ± 2.07 %; 0.13 ± 0.17 mg/kg) was significantly higher than in healthy, celiac, and obese children (p < 0.0001), possibly linked to colonic dyshomeostasis, oxidation, and inflammation. Overall, FeBA depends on food type, preparation method, and gut health status, and is mainly driven by small intestinal absorption.