Folates from metabolically engineered rice: a long-term study in rats.

Scope The biological impact of folates from folate rice, a metabolically engineered (biofortified) rice line, rich in folates, was investigated. Its consumption may be helpful to fight folate deficiency. Our objective was to investigate the potential of folate rice to supply the organism with folates and evaluate its biological effectiveness using a rat model. Methods and results Five groups of 12 Wistar rats were monitored during a 7/12-wk depletion/repletion trial. Animals receiving folate-free diet (0 μg/rat/day) and those additionally receiving wild-type rice (on average 0.11 μg/rat/day) suffered from decreased hematocrit and lower folate concentrations in both plasma and RBCs. This resulted in serious morbidity and even lethality during the trial. In contrast, all animals receiving a daily supplement of folate rice or folic acid fortified rice (on average 3.00 μg/rat/day and 3.12 μg/rat/day, respectively) and those receiving a positive control diet (11.4 to 25.0 μg/rat/day), survived. In these groups, the hematocrit normalized, plasma and RBC folate concentrations increased and pronounced hyperhomocysteinemia was countered. Conclusion Using an animal model, we demonstrated that biofortified folate rice is a valuable source of dietary folate, as evidenced by folate determination in plasma and RBCs, the alleviation of anemia and counteraction of pronounced hyperhomocysteinemia.