Effect of a Millet-based Diet on Micronutrient Status in Adults: A Randomized Pilot Controlled Trial from Delhi, India

Abstract

Background: India faces a high burden of micronutrient deficiencies, specifically vitamin B12, vitamin D, and iron, driven largely by low dietary diversity and the decline of traditional nutrient-rich grains like millets. Aim: This pilot Randomized Controlled Trial (RCT) aimed to assess the current micronutrient status and evaluate the effect of a millet-based diet, alongside oral supplements, on residential adults at the National Association of the Blind (NAB) in Delhi. Methods: Fifty-four participants (aged 18-45) were randomized into two groups for a 60-day intervention: a control group receiving prophylactic oral supplements (vitamin D, vitamin B12, and a multivitamin) and an intervention group receiving the same supplements plus a millet-based diet. Venous blood samples were collected at baseline and endline to measure serum iron, vitamin B12, vitamin D, and haemoglobin. Results: Significant improvements in micronutrient status were primarily observed in female participants. The intervention group showed significantly higher increases compared to the control group in both serum B12 (median change 302 vs. 78 pg/mL; p=0.035) and Vitamin D (49.9 vs. 31.7 ng/mL; p<0.001). While haemoglobin significantly improved within the female intervention group (p=0.009), no significant between-group difference was observed for serum iron. Baseline TSH levels were within the normal reference range, ruling out thyroid-related confounding. Among male participants, changes in vitamin B12 (p= 0.109), vitamin D (p= 0.055) and serum iron (p= 0.87) between the control and intervention group did not reach statistical significance, likely due to a small subgroup sample size. Conclusion: Integrating millets into institutional menus is a feasible and effective strategy to address "hidden hunger" alongside standard supplementation. While oral supplements were the primary drivers for Vitamin D and B12 repletion, the millet diet provided additive benefits, potentially through enhanced absorption or improved adherence, though larger, long-term studies are needed to isolate specific biological mechanisms.