Dose and food matrix effects on selenium retention in mouse tissues from selenium-rich vegetables and rice:...

Selenium (Se) deficiency is a widespread health issue. Investigating the differences in Se bioavailability in agricultural products can provide valuable insights into prioritizing food choices for Se biofortification strategies. This study investigated the effects of food matrix (rice and vegetables) and Se dose on Se retention in tissue by administering SeMet, SeCys₂, MeSeCys, and Se-rich rice and vegetables to mice at varying doses. Results showed that following ingestion of vegetables and rice, Se accumulation in mouse liver and kidneys exhibited non-linear increases with Se doses. Additionally, by giving mice celery, rice, SeMet, SeCys₂, and MeSeCys with different Se doses, Se concentration in liver and kidneys of both male and female mice increased non-linearly with dose, plateauing at higher dose levels, suggesting relative lower retention when doses were higher. This was not due to lower Se absorption in the intestine at higher Se doses, as Se fecal elimination factors (FEFs) in both female and male mice were stable across SeMet doses. However, higher Se doses caused increased urinary excretion, as evidenced by urinary Se excretion factors (UEFs) rising with escalating SeMet doses, leading to lower increases in Se tissue retention under higher Se doses. Further comparing Se tissue retention from rice and celery with same concentrations and species, celery consumption resulted in significantly lower Se accumulation and higher FEFs, suggesting lower Se bioavailability for celery than rice. Our findings demonstrate that Se dose and food matrix collectively shape Se bioavailability, offering a framework to address global deficiencies while balancing efficacy and safety.