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“Other Bio-fortification example – High Zinc Rice” Munirul Islam, International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDRB), Dhaka
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Zinc Biofortification of Rice in Bangladesh
Dr M Munirul Islam, MBBS, PhD
Associate Scientist, Centre for Nutrition & Food SecurityConsultant Physician, Clinical Nutrition Unit
International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR, B)
In collaboration withUniversity of California, Davis and HarvestPlus
Background
Zinc is essential for normal growth and immune function
Zinc supplementation enhances growth in children
Decreases morbidity and mortality from diarrhoea and pneumonia
Although zinc supplementation has been proven effective, coverage of zinc supplementation programs is low
Zinc supplementation at a national scale is a formidable task
Sustainable methods of increasing zinc intakes should be explored
Plant breeding of staple crops, such as rice, to increase the zinc concentration is a promising approach to increase zinc intakes of populations in developing countries
Background
Indicator Information
FAO Food Balance Sheet 70% energy from rice; 3.6% ASF7.4 mg zinc available/person/d
P:Z = 2850% at risk of inadequate intake
Why zinc biofortified rice in Bangladesh?
Indicator Information
FAO Food Balance Sheet 70% energy from rice; 3.6% ASF7.4 mg zinc available/person/d
P:Z = 2850% at risk of inadequate intake
Prevalence stunting, children <5 yr 43%(BDHS, 2007)
Why zinc biofortified rice in Bangladesh?
Indicator Information
FAO Food Balance Sheet 70% energy from rice; 3.6% ASF7.4 mg zinc available/person/d
P:Z = 2850% at risk of inadequate intake
Prevalence stunting, children <5 yr 43%(BDHS, 2007)
Prevalence low serum zinc conc. (<65 µg/dL)
45% infants (Baqui, 2005)59% children (Kongsbak, 2006)
Why zinc biofortified rice in Bangladesh?
Indicator Information
FAO Food Balance Sheet 70% energy from rice; 3.6% ASF7.4 mg zinc available/person/d
P:Z = 2850% at risk of inadequate intake
Prevalence stunting, children <5 yr 43%(BDHS, 2007)
Prevalence low serum zinc conc. (<65 µg/dL)
45% infants (Baqui, 2005)59% children (Kongsbak, 2006)
Response to supplementation + morbidity (Baqui,2002)+ morbidity (Brooks, 2005) + growth (Larsen, 2010)
Why zinc biofortified rice in Bangladesh?
Currently there is a serious lack of recommendation for policy and programmes to prevent zinc deficiency at population levels
Introduction of a rice biofortified with zinc can be an option for such preventive strategy
We anticipate that the additional absorbed zinc will be equivalent to ~40% of the daily absorbed zinc requirement, which is the current minimal target level for zinc biofortified rice
Background
Overview of rice zinc-biofortification project in Bangladesh
Collaboration among plant scientists at BRRI and IRRI and nutrition scientists at ICDDR,B and UC Davis; support provided by HarvestPlus, IAEA
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
Zinc absorption from local diets containing conventional and zinc-biofortified rice measured in young children
Measure impact on zinc status and function of population
Study design – dietary studies
PirgachaTrishal
Cross-sectional survey in two sites, with 2-stage cluster sampling
24 clusters per site, 10 HH percluster
Total 480 children ages 24-48 mo
Methods Dietary intake by direct observation/food weighing in homes
2 non-consecutive days within one week
12-hr breastmilk intake by test weighing, extrapolated to 24 hr
MethodsWeight and height
Serum zinc concentrations and infection status indicators (CRP/AGP)
Rice and lentil samples were analyzed for mineral and phytate content
Child Characteristics
Trishaln=239
Pirgachan=240
Age, mo mean ± SD 35.5 ± 7.0 35.5 ± 7.1Males % 56.7 56.3Breastfeeding % 50.2 50.8Underweight (<-2 WAZ) % 43.8 43.0Stunted (<-2 HAZ) % 64.3 48.3Wasted (<-2 WHZ) % 11.2 12.3
Data from Arsenault et al, J Nutr, 2010
Adjusted serum zinc concentrations
Trishaln=143
Pirgachan=136
Serum zinc (µg/dL) mean ±SD 69 ±11 79 ±12
<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
Data from Arsenault et al, J Nutr, 2010
Usual rice and zinc intake distributionsTrishaln=226
Median (25th, 75th)
Pirgachan=237
Median (25th, 75th)
Rice, raw (g/d) 145(112, 180)
125(90, 164)
Zinc (mg/d) 2.4(2.0, 2.9)
2.5(2.1, 3.0)
Animal source zinc (mg/d) 0.39(0.23, 0.61)
0.67(0.46, 0.95)
Data from Arsenault et al, J Nutr, 2010
Food sources of zinc (%)Trishal Pirgacha
1 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
Data from Arsenault et al, J Nutr, 2010
Zinc biofortified rice simulations Current rice zinc content ~ 0.9 mg/100 g uncooked rice
Selective rice breeding estimated to increase the zinc content by ~ 0.8 mg per 100 g
Random samples of 35% and 70% of the children were selected to simulate different levels of adoption of zinc biofortified rice
Data from Arsenault et al, J Nutr, 2010
Current and simulated prevalence of inadequate zinc intakes
Adequacy level is EAR of 2 mg zinc for 1-3 y old children (IZiNCG)
0
5
10
15
20
25
30
Current 35% 70%
%
TrishalPirgacha
Data from Arsenault et al, J Nutr, 2010
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
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
J. Nutr. 140: 1683–1690, 2010
Will increased zinc intake improve zinc status and health outcomes?
Absorption of zinc from mixed diets containing conventional or zinc-biofortified Bangladeshi rice among young children in a
peri-urban community
Specific Aim To estimate the amount of zinc absorbed (bioavailability)
from zinc-biofortified rice compared with conventional rice, using a triple stable isotope tracer ratio technique in young children in Bangladesh
Study design
Controlled clinical study – within-child, cross-over design
Zinc absorption measured in children:
Zinc-biofortified rice-based diet (Diet-ZnBfR) vs conventional rice-based diet (Diet-CR)
Methods
Study participants
22 children aged 36-59 mo, either sex, from peri-urban community
WHZ and HAZ: >-2 Z
No H/O diarrhoea or zinc supplements in past 14 days
Anti-helminthics provided if not received in past 3 months
Methods
Subject recruiting site: Nandipara
10 km away from Centre
Rice samples
Zinc Biofortified Rice (ZnBfR)
Conventional Rice(CR)
Planned amounts of dietary components and zinc contents
Diet Component CR diet ZnBfR diet
Amt Zinc Amt ZincBR-28 (CR) 150 2.02 - -
IR-68144 (ZnBfR) - - 150 3.90
Lentils (as soup) 30 1.09 30 1.09
Fried green papaya 100 0.17 100 0.17
Zinc tracer 0.33 mg 70Zn
1.00 1.00 mg 67Zn
1.00
Total Zinc 4.28 6.16
Diets provided energy: 841 kcal/d; protein 18.6 g/d, and dietary phytate: zinc ratio=41 (CR) or 43 (ZnBfR)
Baseline fasting blood and urines
Admit to study ward
Study days 1 2 3 4 5 6 7 8 9 10
Absorption study protocol
1. Diet-ZnBfR + 67ZnOR
2. Diet-CR + 70Zn
Baseline fasting blood and urines
Admit to study ward
Study days 1 2 3 4 5 6 7 8 9 10
Absorption study protocol
1. Diet-ZnBfR + 67ZnOR
2. Diet-CR + 70Zn
Baseline fasting blood and urines
1. Diet-CR + 70ZnOR
2. Diet-ZnBfR + 67Zn
Admit to study ward
Study days 1 2 3 4 5 6 7 8 9 10
Absorption study protocol
1. Diet-ZnBfR + 67ZnOR
2. Diet-CR + 70Zn
Baseline fasting blood and urines
1. Diet-CR + 70ZnOR
2. Diet-ZnBfR + 67Zn
Admit to study ward
IV 68Zn infusion, 4 hours after dinner
Study days 1 2 3 4 5 6 7 8 9 10
Absorption study protocol
1. Diet-ZnBfR + 67ZnOR
2. Diet-CR + 70Zn
Baseline fasting blood and urines
1. Diet-CR + 70ZnOR
2. Diet-ZnBfR + 67Zn
Admit to study ward
IV 68Zn infusion, 4 hours after dinner
Spot urines for Zn Isotope Ratios
Study days 1 2 3 4 5 6 7 8 9 10
Absorption study protocol
Discharge from study ward
Diet Preparation
Feeding
MethodsTracer protocol for zinc absorption studies:
Triple isotope tracer ratio method
Isotope (68Zn) was given as an intra-venous dose
Isotope (67Zn) was added to the diet when receiving Zinc biofortified rice diet (ZnBfR), 1 mg/d
Isotope (70Zn) was added when receiving control rice (CR), 0.33 mg/d + 0.67 mg/d unenriched zinc
Oral tracers were served as a flavored drink at the end of each meal
MethodsTracer protocol for zinc absorption studies:
Administration of oral isotope
Methods
On day 3, after 4 hours following the dinner time, under all aseptic and universal precautions, 1 mg of 68ZnCl2was infused very slowly to the children mixed with 2 ml normal saline over 10 minutes
Tracer protocol for zinc absorption studies:
MethodsTracer protocol for zinc absorption studies:Administration of intra-venous isotope
MethodsTracer protocol for zinc absorption studies:Administration of intra-venous isotope
MethodsSample collection:
Blood was collected on day 2: Blood Hb%, serum zinc, serum ferritin, serum C-Reactive Protein (CRP), and serum α-1 acid glycoprotein (AGP)
Urine samples: on day 2 at the study ward and 6, 7, 8, 9 and 10 from respective homes of the study subjects
Methods
Urine sample processing
MethodsEstimation and calculation of zinc absorption from ZnBfR (67Zn oral tracer, 68Zn IV tracer):
Zinc isotopic ratios measured in chromatography-purified urine samples, by using ICP- MS (USDA WHNRC)
FZA = (67Zn tracer : tracee ratio / 68Zn tracer : tracee ratio) X (68Zn dose given IV / 67Zn dose given orally)
Total absorbed zinc (TAZ) for each child calculated as:TAZ (mg/d) = TDZ (mg/d) X FZA (%)
Results
Variables (n=22)
Age (mo) 46.2 ± 6.1
SexMaleFemale
148
Mother’s age (year) 25.5 ± 4.6
Maternal education (school year)* 5 (0, 6.3)
Father’s education (school year)* 3.7 (1.5, 8.3)
Family income (US$/mo) 83 ± 40
* Median (25th, 75th )
Socio-Demographic Characteristics
Anthropometry
Variables (n=22)
Body weight (kg) 13.76 ± 1.5
Length (cm) 97.0 ± 4.2
Weight-for-Height (Z-score)* 0.71 (-1.21, -0.16)
Height-for-Age (Z-score)* -1.3 (-1.72, -0.59)
* Median (25th, 75th )
Results
Biochemical parameters
Variables (n=21)
Hemoglobin (g/dl) 11.98 ± 1.03
Plasma zinc (µg/dL) 80 ± 9
Serum ferritin (ng/ml) 36.65 ± 18.6
C-reactive protein (mg/L)* 0.5 (0.3, 1.4)
Alpha1-Glycoprotein (mg/dl) 84.88 ± 29.7
* Median (25th, 75th )
Results
Total Dietary Zinc (TDZ) by dietary sources and dietary period (n=21)
Total Dietary Zinc (TDZ), mg/d Conventional Rice
Biofortified Rice
Composite diet (mg/d) 2.640 3.634Banana, ad libitum (mg/d) 0.162 0.182Tracer and unenriched zinc (mg/d) 1.014 1.000
Total 3.816 4.816
Estimated P:Z molar ratio 27 25
Results
Zinc Intakes and Absorption by dietary period (n=21)
Conventional Rice
Biofortified Rice P value
Total Dietary Zinc (TDZ) Intake (mg/d)
3.816 4.816 -
Fractional Zinc Absorption (FZA) (%)
25.2 ± 1.3 19.6 ± 1.6 <0.0001
Total Absorbed Zinc (TAZ) (mg/d)
0.961 ± 0.16 0.943 ± 0.16 0.984
Results
Conclusions
Zinc intake from ZnBfR diet ~1 mg/d greater than from CR among children consuming 150 g rice/d (dry weight)
FZA was greater for CR than ZnBfR, probably due to higher zinc intake with ZnBfR and similar P:Z; no detectable difference in TAZ
Plant breeders may need to increase zinc content of ZnBfR (and/or decrease phytate content) to increase total absorbed zinc by young children
Next steps
Repeat tracer studies with different cultivar(s) of ZnBfR
Community-based efficacy trial when greater TAZ can be confirmed
Consider studies in women?
Kenneth H Brown, Leslie R Woodhouse. UC Davis, WHNRCBakhtiar Hossain, Tahmeed Ahmed, Nazmul Huda, TanveerAhmed. ICDDR,BChristine Hotz, Erick Boy. HarvestPlus
Co-Investigators
Agencies and technical partners
HarvestPlus Challenge Program, HarvestPlusInternational Atomic Energy Agency (IAEA), Vienna, AustriaBangladesh Rice Research Institute (BRRI)
ICDDR, B staff and Residents of the community
Acknowledgments
Research Team
Thank you