What question did this study set out to answer?

This research aims to compare total absorbed zinc in children consuming different rice varieties and zinc fortificants.

February 21, 2026Open Access

Absorption of zinc from mixed diets containing conventional Bangladeshi rice, zinc-biofortified Bangladeshi rice, or conventional Bangladeshi rice with added zinc among young children from a peri-urban community in Bangladesh.

Key Points

This research aims to compare total absorbed zinc in children consuming different rice varieties and zinc fortificants.
Cross-over study design involving 47 children aged 36-59 months.
Children received diets containing either low-zinc conventional rice, zinc-fortified conventional rice, or zinc-biofortified rice.
Zinc absorption was measured using a triple-isotope tracer technique.
Total zinc intake was highest with zinc-biofortified rice and lowest with low-zinc conventional rice.
Mean fractional zinc absorption was significantly greater for zinc-biofortified rice compared to the other diets.
Zinc-biofortified rice satisfied a higher percentage of the daily zinc requirement for young children compared to low-zinc rice.

Abstract

Previous studies showed total absorbed zinc (TAZ) was comparable in diets containing a higher zinc rice variety or conventional rice variety (Lo-Zn CR). This study compared TAZ in a polished zinc-biofortified rice (Hi-Zn BfR) compared to Lo-Zn CR. Measure the amount of TAZ by young Bangladeshi children from Hi-Zn BfR, Lo-Zn CR, or CR plus sufficient exogenous zinc fortificant (Lo-Zn CR+Zn) matching the zinc content of Hi-Zn BfR. 47 children 36-59 mo old were enrolled in a cross-over study. On the day 1, children received a Lo-Zn CR diet. On days 2 and 4, group A (n=23) received 150 g of Lo-Zn CR and group B (n=24) received 150g of Lo-Zn CR+Zn as part of a mixed diet. On days 3 and 5, both groups received 150 g of Hi-Zn BfR. Fractional zinc absorption (FZA) was measured in all diet periods using a triple-isotope tracer (oral 67-Zn and 70-Zn; intravenous 68-Zn) ratio technique; TAZ was calculated as product of zinc intake (TDZ) and FZA. TDZ was 4.88, 6.14, and 6.70 mg/day when fed Lo-Zn CR-, Lo-Zn CR+Zn- and Hi-Zn BfR- containing diets, respectively. Mean FZA: 0.23 ± 0.041, 0.169 ± 0.035 and 0.212 ± 0.048 for respective diets (Lo-Zn CR vs Hi-Zn BfR: p=0.26; Lo-Zn CR+Zn vs Hi-Zn BfR: p <0.001; and Lo-Zn CR vs. Lo-Zn CR+Zn: p <0.001). Mean TAZ from respective diets were 1.13 ± 0.23, 1.04 ± 0.20 and 1.40 ± 0.33mg/day. TAZ was not significantly different between Lo-Zn CR and Lo-Zn CR+Zn diets (p =0.52) but was significantly more in Hi-Zn BfR when compared with other two diets (p <0.001 for both). A single day ration (150 g total) in 3 equally divided servings of Hi-Zn BfR could satisfy 47% of the recommended daily requirement of zinc (3 mg/day) for children 1-3 years old and 28% for children 4-8 years old (5 mg/day) compared to 37% and 23% from Lo-Zn CR for the same age groups, respectively. Hi-Zn BfR is a meaningful component of preventative option for childhood zinc deficiency where rice is staple. The study is registered with https://www.ClinicalTrials.gov as Clinical Trial identifier # NCT04099849.

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