In vitro bioaccessibility and bioavailability of selenium in agronomic biofortified wheat

Selenium is an important mineral for humans, and it is often necessary to supplement it in the human diet, not only due to low intake but also mainly because ingested selenium is not effectively absorbed and used by the body in its vital functions. Considering the high global consumption of wheat and the efficiency demonstrated by wheat in biofortification studies, the evaluation of bioaccessible and bioavailable Se fractions in (5, 10 and 20 g ha−1) agromomic biofortified wheat grains was performed. For the bioaccessibility experiments, in vitro simulation of digestion in the oral, gastric and intestinal phases was used, whereas bioavailability was evaluated using a cellular model with Caco-2 cells. The bioaccessible fraction of Se enhances with the increase of Se in wheat grains and represented, on average, 63.6–93.8% of the total fraction. However, the bioavailability experiments showed that approximately 65 % of Se is not taken up the cells and that only about 19.6 % is absorbed by the human body, for all the doses investigated. The results of this study show that the nutritional contents of biofortified foods should take into account the fractions absorbed by the body and not only the total contents as established by law.