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Biofortified Rice for Bangladesh: Plan, Findings and Directions

Erick Boy, MD, Ph.D. Nutrition CoordinatorHarvestPlus

April 18, 2012

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

Estimate the Target Level

Efficacy Trial

Effectiveness

Development

Evaluation

Consumption Level

Food Retention

Bioavailability

Hotz & McClafferty, 2007FNB, 28 (2), S271-79

HarvestPlus Biofortified 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

Preliminary nutrient target assumptions for parboiled polished rice:

Dietary and Zn status survey

PirgachaTrishal

Cross-sectional survey in two sites, with 2-stage cluster sampling

24 clusters per site, 10 HHs/cluster

Total 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 zinc

Prevalence Trishaln=143

Pirgachan=136

Stunted (< -2 HAZ)

64.3 48.3

Deficient(<65 µg/dL)

36 11

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 Pirgacha

1 Rice 58.9 Rice 40.7

2 Fish 6.9 Dairy 7.2

3 Lentils 6.7 Egg 6.9

4 Dairy 5.0 Potato 4.7

5 Vegetables1 3.9 Fish 4.4

6 Egg 2.4 Lentils 4.4

7 Biscuit/cookie 2.2 Beef 4.48 Spices 1.8 Other legumes 3.6

9 Potato 1.8 Biscuit/cookie 3.2

10 Breastmilk 1.7 Vegetables1 3.2

1 vegetables other than potatoes or green leafy vegetables

Current and simulated prevalence of inadequate zinc intakes

Adequacy level is EAR of 3 mg zinc for 4-6 y old children (IZiNCG)

25.2

17

9.4

1813.4

7.9

05

1015202530

Current 35% 70%

%

TrishalPirgacha

Data from Arsenault et al, J Nutr, 2010

Biofortified Rice Adoption (%)

Conclusions – dietary studies

Young children in Bangladesh have a high prevalence of zinc deficiency

Rice is the primary source of dietary zinc

Increasing zinc content of rice will improve the adequacy of zinc intakes in this population

Will increased zinc intake improve zinc status and health outcomes?

Zinc absorption studies

Objective:- Assess zinc absorption from local Bangladeshi diets containing conventional or biofortified rice among young, non-breast fed children

Measurements:- 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

• Within-child, cross-over design• 42 children, 36-59 mo, WHZ>-2• Conventional vs Biofortified vs Fortified

Pilot Study Methods – ICDDR,B and University of California-Davis

2.40 mg Zn/100 g unwashed, milled, raw (2.2 ppm washed)

1.35 mg Zn/100 g unwashed, milled, raw (1.2 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

Zn Intake by GroupDietary component CR ZnBfR CR +Zn

Composite diet (mg/d)* 2.84 3.81 2.85Zinc tracer + non- enriched zinc (mg/d)*

1.01 1.00 3.18

Total measured zinc intake (mg/d)

3.81 4.81 6.03

Estimated phytate : zinc molar ratio

20 22 13

Total dietary zinc (TDZ) by dietary source and dietary period

CR ZnBfR CR +Zn(n=20)

p-value*

Total dietary zinc intake (mg/d)

3.81 4.81 6.03

Fractional zinc absorption (%)

25.1 ± 4.1a 20.7 ± 4.2b 18.8 ± 3.4c <0.001

Total absorbed zinc (mg/d)

0.96 ±0.16a 1.0 ± 0.2a 1.13 ± 0.20b

<0.001

*p-value for ANOVA comparing three dietary periods (two ZnBfR periods combined). Dietary periods with different superscripts are significantly different, p<0.05.

Total dietary zinc intake and fractional and total zinc absorption from rice

Absorption from Pearl Millet Test Meals

GroupAge, mo

Fractional Absorption of Zn

(%)Absorbed Zn,

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 + 0.24

P value 0.32 0.15 0.03

Personal 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

ff

Next steps

2013: 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

Thank you!

Group A1. Diet-ZnBfR + 67Zn

OR2. Diet-CR + 70Zn

Baseline fasting blood and urines

Group A1. Diet-CR + 70Zn

OR2. Diet-ZnBfR + 67Zn

Admit to study ward

IV 68Zn infusion, 4 hours after dinner

Spot urines for Zn Isotope Ratios

Discharge from study ward

Study days 1 2 3 4 5 6 7 8 9 10

Study protocol