Collaborative effort of…. Working with…. (rice) … to assess 1, 2, 3…
Here is the scheme of the nutrition research. In the development stages of the biofortified maize, the main question is by much do we need to increase the PVA levels. What is the target level? And to answer this question we need to know how much maize will people eat? How much of PVA is lost during the cooking process and how much stays in the food and how much is absorbed by the body. Then we will do an efficacy trial with to determine the impact of the PVA maize on the Vitamin A status of the study population under controlled conditions Effectiveness: when the PVA maize is made available to population to study the results on improved levels of vitA and health
This was a cross-sectional survey with 2-stage cluster sampling in 2 rural rice-growing regions of Bangladesh – Trishal and Pirgacha districts. In each site, there were 24 clusters with 10 households per cluster. The total sample size was 480 children ages 24-48 mo.
Since serum zinc is impacted by inflammatory status and the time of day of blood sampling, we adjusted the serum zinc values using estimates from a regression model that included indicators of elevated acute phase proteins (AGP and CRP) and the time of day of blood sampling. The mean serum zinc concentrations were 10 microgram per deciliter lower in Trishal than Pirgacha. Overall, 24% of children had low serum zinc concentrations, and the prevalence of low serum zinc concentrations was higher in Trishal.
These are the major food sources of zinc as a percentage of total daily zinc. Rice was the main source of zinc. There were low intakes of zinc from animal foods, especially in Trishal.
Adequacy of zinc intakes were assessed using an Estimated Average Requirement of 2 mg/d. Children in Trishal had a higher prevalence of inadequate zinc intakes – 25% vs. 18% in Pirgacha. If 35% of the children consumed zinc-biofortified rice, the prevalence of inadequacy decreased to ~ 17 and 13%; and if 70% of the children consumed zinc-biofortified rice, the prevalence of inadequacy decreased to about 8-9%.
Young children in Bangladesh have a high rate of zinc deficiency. Rice is the primary source of dietary zinc, and increasing the zinc content of rice will improve the adequacy of zinc intakes in this population. The next question is will increased zinc intakes improve zinc status and health outcomes? Future studies are underway to address these questions.
The primary aim of this study was to assess current dietary intakes of rice and zinc in rural rice-growing regions of Bangladesh as a first step in planning future studies for zinc-biofortified rice. With this baseline dietary intake data, we simulate the potential impact of increasing the zinc content of rice on the adequacy of zinc intakes of children. Specific aims were to assess anthropometric and zinc status of children, collect quantitative data on rice and total zinc intakes, assess adequacy of zinc intakes, and simulate zinc intakes if the rice zinc content were increased. In this study, the children were not consuming zinc-biofortified rice, this was a simulation exercise using the data on current rice and zinc intakes.
-The Case of Iron-Biofortified Rice Research in the Philippines .
Erick Boy - Biofortified rice for Bangladesh: Plan, Findings and Directions
Biofortified Rice for Bangladesh: Plan, Findings and Directions Erick Boy, MD, Ph.D. Nutrition Coordinator HarvestPlus April 18, 2012HarvestPlus c/o IFPRI2033 K Street, NW • Washington, DC 20006-1002 USATel: 202-862-5600 • Fax: 202-467-4439HarvestPlus@cgiar.org • www.HarvestPlus.org
Overview of rice zinc biofortification project in Bangladesh– Collaboration among plant scientists at BRRI and IRRI and nutrition scientists at ICDDRB and UC Davis– High-zinc rice cultivars back-crossed into local varieties with desirable agronomic traits– Potential impact on dietary zinc intake assessed in young children and women of reproductive age (dietary & Zn status survey)– Zinc absorption from local diets containing conventional and zinc-biofortified rice measured in young children (Zn absorption studies)– Measure impact on zinc status and function of population (efficacy trial)
Nutrition Research ConsumptionDevelopment Level Estimate the Food Retention Target Level BioavailabilityEvaluation Efficacy Trial Effectiveness Hotz & McClafferty, 2007
HarvestPlus Biofortified Rice Preliminary nutrient target assumptions for parboiled polished rice:• Target Countries: Bangladesh & India• Assumed average consumption/d: 400g (adult woman) & 200 g (child 4-6 yr)• Average baseline zinc content: 16 µg/g polished• Retention (polished rice) after cooking: 90%• Assumed absorption: 25%• Estimated contribution to Daily Requirement (EAR): 40%• Increase by plant breeding: 8 µg/g• Preliminary target: 24 µg/g
Dietary and Zn status surveyCross-sectional survey in two sites,with 2-stage cluster sampling Pirgacha Trishal24 clusters per site, 10 HHs/clusterTotal 480 children ages 24-48 mo • Weight, Height, serum zinc • Food (rice & zinc) intake • Zn & phytate in rice and lentils from homes
Indicators of Zinc deficiency in Children (%) 25% low serum zincPrevalence Trishal Pirgacha n=143 n=136Stunted (< -2 64.3 48.3HAZ)Deficient 36 11(<65 µg/dL) Plasma zinc values adjusted using estimates from a regression model that included indicators of elevated acute phase proteins and the time of day of blood sampling
Food sources of zinc (%) Trishal Pirgacha1 Rice 58.9 Rice 40.72 Fish 6.9 Dairy 7.23 Lentils 6.7 Egg 6.94 Dairy 5.0 Potato 4.75 Vegetables1 3.9 Fish 4.46 Egg 2.4 Lentils 4.47 Biscuit/cookie 2.2 Beef 4.48 Spices 1.8 Other legumes 3.69 Potato 1.8 Biscuit/cookie 3.210 Breastmilk 1.7 Vegetables1 3.2 1 vegetables other than potatoes or green leafy vegetables
Current and simulated prevalence of inadequate zinc intakes 30 25.2 25% 20 18 17 13.4 Trishal 15 Pirgacha 9.4 10 7.9 5 0 Current 35% 70% Biofortified Rice Adoption (%) Adequacy level is EAR of 3 mg zinc for 4-6 y old children (IZiNCG) Data from Arsenault et al, J Nutr, 2010
Conclusions – dietary studiesYoung children in Bangladesh have a high prevalence of zinc deficiencyRice is the primary source of dietary zincIncreasing zinc content of rice will improve the adequacy of zinc intakes in this populationWill increased zinc intake improve zinc status and health outcomes?
Zinc absorption studiesObjective: - Assess zinc absorption from local Bangladeshi diets containing conventional or biofortified rice among young, non-breast fed childrenMeasurements: - Fractional zinc absorption (FZA), using triple isotope ratio method - Total zinc absorption (TZA) = dietary zinc * FZA• Pilot study with IRRI elite line: • Definitive study with BR Zinc biofortified Line: 2013
Pilot Study Methods – ICDDR,B and University of California-Davis• Within-child, cross-over design• 42 children, 36-59 mo, WHZ>-2• Conventional vs Biofortified vs Fortified 1.35 mg Zn/100 g unwashed, 2.40 mg Zn/100 g unwashed, milled, raw (1.2 ppm washed) milled, raw (2.2 ppm washed)
IR68144: a serendipitous finding of the mid 1990s IRRI elite line IR68144-3B-2-2-3, or IR68144 for short -- the cross between cultivars IR72 and Zawa Bonday, selected for their agronomic suitability for “cold elevated areas” and aromatic quality. East Asian Science, Technology and Society: An International Journal (2011) 5:173–188 IR68144-3B-2-2-3, IRRI, Los Baños. Copyright: Michael Rubinstein,International Food Policy Research Institute, 2003
Total dietary zinc (TDZ) by dietary source and dietary period Zn Intake by GroupDietary component CR ZnBfR CR +ZnComposite diet (mg/d)* 2.84 3.81 2.85Zinc tracer + non- enriched 1.01 1.00 3.18zinc (mg/d)*Total measured zinc intake 3.81 4.81 6.03(mg/d)Estimated phytate : zinc 20 22 13molar ratio
Total dietary zinc intake and fractional and total zinc absorption from rice CR ZnBfR CR +Zn p- (n=20) value*Total dietary zinc 3.81 4.81 6.03intake (mg/d)Fractional zinc 25.1 ± 4.1a 20.7 ± 4.2b 18.8 ± 3.4c <0.001absorption (%)Total absorbed 0.96 ±0.16a 1.0 ± 0.2a 1.13 ± <0.001zinc (mg/d) 0.20b *p-value for ANOVA comparing three dietary periods (two ZnBfR periods combined). Dietary periods with different superscripts are significantly different, p<0.05.
Absorption from Pearl Millet Test Meals Fractional Group Absorption of Zn Absorbed Zn, Age, mo (%) mg/d Hi Iron/Zn 28 + 4 17.1 + 8.1 0.95 + 0.47 Low iron/Zn 29 + 3 20.2 + 4.2 0.67 + 0.24P value 0.32 0.15 0.03Personal communication. Hambidge M, B. Kodkani. 2012A: 87 ug Zn/g millet; 9.4 mg phytate/g milletB: 44 ug zn/g millet; 9.8 mg phytate/g millet
Next steps2013: Conduct stable isotope tracer studies with different cultivar(s) of ZnBfR (> 2 mg dietary Zn difference, phytate constant) Direct analyses of zinc & phytate in food components before/during Zn absorption trial. Laboratory capacity strengthening ICDDR,B (phytate analysis)2013-14: Conduct community-based efficacy trial when greater Total Absorbed Zinc from ZnBfR is confirmed
Study protocol Baseline fasting blood and urines Group A 1. Diet-ZnBfR + 67Zn OR 2. Diet-CR + 70Zn Group A 1. Diet-CR + 70Zn OR 2. Diet-ZnBfR + 67ZnAdmit to IV 68Zn infusion, 4 hoursstudy ward after dinner Discharge from study ward Study days 1 2 3 4 5 6 7 8 9 10 Spot urines for Zn Isotope Ratios