Vitamin A-fortified rice increases total body vitamin A stores in lactating Thai women measured by retinol isotope dilution: a double-blind, randomized, controlled trial.

BACKGROUND: Lactating women are at increased risk for vitamin A (VA) deficiency due to demands for breast milk content and limited hepatic stores for women in some countries. Previously, consumption of triple-fortified rice, which included VA, iron, and zinc, successfully improved the VA status of Thai children in whom their total body VA stores (TBSs) were doubled in 2 mo. OBJECTIVE: This study assessed the efficacy of consuming VA-fortified rice, which delivered 500 µg retinol activity equivalents (RAEs)/d, on TBSs and estimated total liver VA reserves (TLRs) in Thai lactating women using the retinol isotope dilution (RID) test. METHODS: A randomized controlled trial was conducted with 70 lactating women (n = 35/group) who received either VA-fortified rice (500 µg RAEs/d) or unfortified rice for 14 wk on weekdays only. Serum retinol concentrations (SRs), C-reactive protein, and TBSs were assessed before and after the intervention. The paired 13C-RID test was used to measure TBSs. After a baseline blood sample, 2.0 µmol [14,15]-13C2-retinyl acetate was administered orally. A follow-up blood sample was drawn 14 d later. The RID test was repeated after the intervention. RESULTS: TBSs increased significantly (P < 0.05) in the intervention group from 240 (182, 316) to 331 (251, 447) [geometric means (95% CIs)] µmol retinol, and this change in TBSs was significantly higher (P < 0.05) than that in the control group [+52.9 (-74, 453) compared with -4.3 (-106, 275) µmol retinol]. Estimated TLRs indicated a high prevalence of VA deficiency among these lactating women. Initial and final SRs did not differ by group and did not change over the course of the intervention. CONCLUSION: VA-fortified rice improved the VA status of lactating women by increasing TBSs. A targeted approach to disseminate VA interventions among vulnerable groups should be considered in some contexts. This trial was registered at clinicaltrials.gov as NCT03056625.

Triple-fortified rice containing vitamin A reduced marginal vitamin A deficiency and increased vitamin A liver stores in school-aged Thai children.

Vitamin A (VA)-fortified rice is a potential intervention strategy to prevent VA deficiency in at-risk populations. Hot-extruded, triple-fortified rice grains with added VA, zinc, and iron were produced by hot extrusion technology and their ability to improve VA status was tested in Thai schoolchildren. The fortification levels were 10 mg of iron, 9 mg of zinc, and 1.05 mg of VA/g extruded rice. A paired stable isotope dilution technique with labeled ¹³C2-retinyl acetate (¹³C-RID) was used to quantify VA pool size at the beginning and end of the feeding period. Fifty healthy schoolchildren with a serum retinol (SR) concentration of >0.7 µmol/L were randomly assigned to 2 groups to receive either triple-fortified rice (n = 25) or natural rice (n = 25) for 2 mo as part of the daily school meal. The fortified grains, mixed 1:50 with regular rice, were estimated to provide an extra 890 µg of VA/d, 5 d/wk. ¹³C2-retinyl acetate (1.0 µmol) was administered orally to each child before and at the end of the feeding period to estimate total body reserves (TBRs) of VA, which increased significantly (P < 0.05) in the intervention group from 153 ± 66 µmol retinol at baseline to 269 ± 148 µmol retinol after 2 mo of feeding. There was no change in the TBRs of VA in the control group (108 ± 67 vs. 124 ± 89 µmol retinol) (P = 0.22). Serum retinol remained unchanged in both groups. We conclude that VA-fortified, hot-extruded rice is an efficacious vehicle to provide additional VA to at-risk populations, and that the efficacy of VA-fortified foods can be usefully monitored by the ¹³C-RID measurement of TBRs of VA but not by changes in SR concentration.

Extruded rice grains fortified with zinc, iron, and vitamin A increase zinc status of Thai school children when incorporated into a school lunch program.

Iron (Fe), zinc (Zn), and vitamin A (VA) deficiencies are common among children in developing countries and often occur in the same individual. Rice is widely consumed in the developing countries of Asia and the low phytate in polished rice makes it ideal for Zn and Fe fortification. Triple-fortified rice grains with Zn, Fe, and VA were produced using hot extrusion technology. The main objective of the present study was to determine the impact of triple-fortified extruded rice on Zn status in school children in Southern Thailand. Although serum zinc was the main outcome indicator, Fe and VA status were also assessed. School children with low serum zinc (n = 203) were randomized to receive either triple-fortified rice (n = 101) or natural control rice (n = 102) as a component of school lunch meals for 5 mo. Serum Zn, hemoglobin, serum ferritin, serum retinol, and C-reactive protein were measured at baseline and at the end of the study. After the intervention, serum Zn increased (P < 0.05) in both the fortification (11.3 ± 1.3 µmol/L) and control (10.6 ± 1.4 µmol/L) groups, most likely due to the proper implementation of the school lunch and school milk programs, with the increase greater in the group receiving the triple-fortified rice (P < 0.05). Because the children were not Fe or VA deficient at baseline, there was no change in Fe or VA status. We conclude that Zn fortification of extruded rice grains is efficacious and can be used to improve Zn status in school children.