Iron biofortification interventions to improve iron status and functional outcomes

Systematic review of 3 randomized efficacy trials with 633 participants pooled across active arms. Participants were adolescents and adults at risk of iron deficiency, including adult religious sisters in the Philippines, adolescents in hostels in India, and iron-depleted female university students in Rwanda.

Iron-biofortified staple crops were tested as daily oral food-based interventions: biofortified rice for 9 months in the Philippines, biofortified pearl millet for 6 months in India, and biofortified beans twice daily for 128 days in Rwanda. Comparator crops were conventional varieties with lower iron content.

Iron-biofortified crops improved cognitive performance in attention and memory domains compared with conventional crops. Overall, however, they did not show significant effects on anaemia or iron deficiency. In the rice trial, ferritin increased in non-anaemic participants (P = 0.02) and total body iron increased (P = 0.05) versus conventional rice, but cognitive outcomes were not reported there. Evidence for physical performance and other functional outcomes remains limited.

Evidence came from only 3 randomized efficacy trials with different crops, populations, and durations, limiting certainty and generalizability. Outcomes were incomplete across trials, physical performance evidence was sparse, and several key results were available only for specific subgroups rather than the full pooled population.