- Zinc is essential for growth and immune function in children, and zinc supplementation has been shown to improve growth, reduce morbidity, and mortality. However, zinc supplementation programs have low coverage. - Zinc biofortification of staple crops like rice is a promising strategy to increase zinc intake in developing countries. The study assessed zinc absorption from diets containing conventional or zinc-biofortified rice in Bangladeshi children. - Using stable isotope tracers, the study found fractional zinc absorption was significantly higher from the conventional rice diet (25.2%) compared to the zinc-biofortified rice diet (19.6%), despite higher total zinc intake from the latter. This suggests zinc biofortification of

1. Zinc Biofortification of Rice in
Bangladesh
Dr M Munirul Islam, MBBS, PhD
Associate Scientist, Centre for Nutrition & Food Security
Consultant Physician, Clinical Nutrition Unit
mislam@icddrb.org
International Centre for Diarrhoeal Disease Research, Bangladesh
(ICDDR, B)
In collaboration with
University of California, Davis and HarvestPlus

2. 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

3.  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

4. Indicator Information
FAO Food Balance Sheet 70% energy from rice; 3.6% ASF
7.4 mg zinc available/person/d
P:Z = 28
50% at risk of inadequate intake
Why zinc biofortified rice in Bangladesh?

5. Indicator Information
FAO Food Balance Sheet 70% energy from rice; 3.6% ASF
7.4 mg zinc available/person/d
P:Z = 28
50% at risk of inadequate intake
Prevalence stunting, children <5 yr 43%
(BDHS, 2007)
Why zinc biofortified rice in Bangladesh?

6. Indicator Information
FAO Food Balance Sheet 70% energy from rice; 3.6% ASF
7.4 mg zinc available/person/d
P:Z = 28
50% 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?

7. Indicator Information
FAO Food Balance Sheet 70% energy from rice; 3.6% ASF
7.4 mg zinc available/person/d
P:Z = 28
50% 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?

8.  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

9. 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

10. Study design – dietary studies
Pirgacha
Trishal
 Cross-sectional survey in two
sites, with 2-stage cluster
sampling
 24 clusters per site, 10 HH per
cluster
 Total 480 children ages 24-48
mo

11. 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

12. Methods
 Weight and height
 Serum zinc concentrations and infection status
indicators (CRP/AGP)
 Rice and lentil samples were analyzed for mineral and
phytate content

13. Child Characteristics
Trishal
n=239
Pirgacha
n=240
Age, mo mean ± SD 35.5 ± 7.0 35.5 ± 7.1
Males % 56.7 56.3
Breastfeeding % 50.2 50.8
Underweight (<-2 WAZ) % 43.8 43.0
Stunted (<-2 HAZ) % 64.3 48.3
Wasted (<-2 WHZ) % 11.2 12.3
Data from Arsenault et al, J Nutr, 2010

14. Adjusted serum zinc concentrations
Trishal
n=143
Pirgacha
n=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

15. Usual rice and zinc intake distributions
Trishal
n=226
Median (25th, 75th)
Pirgacha
n=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

16. 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 4.4
8 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
Data from Arsenault et al, J Nutr, 2010

17. 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

18. 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%
%
Trishal
Pirgacha
Data from Arsenault et al, J Nutr, 2010

19. 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

20. 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

21. Will increased zinc intake improve zinc
status and health outcomes?

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

23. 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

24. 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

25. 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

26. Subject recruiting
site: Nandipara
10 km away from
Centre

27. Rice samples
Zinc Biofortified Rice
(ZnBfR)
Conventional Rice
(CR)

28. Planned amounts of dietary components
and zinc contents
Diet Component CR diet ZnBfR diet
Amt Zinc Amt Zinc
BR-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)

29. Baseline fasting blood
and urines
Admit to
study
ward
Study days 1 2 3 4 5 6 7 8 9 10
Absorption study protocol

30. 1. Diet-ZnBfR +
67
Zn
OR
2. Diet-CR +
70
Zn
Baseline fasting blood
and urines
Admit to
study
ward
Study days 1 2 3 4 5 6 7 8 9 10
Absorption study protocol

31. 1. Diet-ZnBfR +
67
Zn
OR
2. Diet-CR +
70
Zn
Baseline fasting blood
and urines
1. Diet-CR +
70
Zn
OR
2. Diet-ZnBfR +
67
Zn
Admit to
study
ward
Study days 1 2 3 4 5 6 7 8 9 10
Absorption study protocol

32. 1. Diet-ZnBfR +
67
Zn
OR
2. Diet-CR +
70
Zn
Baseline fasting blood
and urines
1. Diet-CR +
70
Zn
OR
2. Diet-ZnBfR +
67
Zn
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

33. 1. Diet-ZnBfR +
67
Zn
OR
2. Diet-CR +
70
Zn
Baseline fasting blood
and urines
1. Diet-CR +
70
Zn
OR
2. Diet-ZnBfR +
67
Zn
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

34. Diet Preparation

35. Feeding

36. Methods
Tracer 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

37. Methods
Tracer protocol for zinc absorption studies:
Administration of oral isotope

38. Methods
On day 3, after 4 hours following the dinner time, under
all aseptic and universal precautions, 1 mg of 68ZnCl2
was infused very slowly to the children mixed with 2 ml
normal saline over 10 minutes
Tracer protocol for zinc absorption studies:

39. Methods
Tracer protocol for zinc absorption studies:
Administration of intra-venous isotope

40. Methods
Tracer protocol for zinc absorption studies:
Administration of intra-venous isotope

41. Methods
Sample 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

42. Methods
Urine sample processing

43. Methods
Estimation 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 (%)

44. Results
Variables (n=22)
Age (mo) 46.2 ± 6.1
Sex
Male
Female
14
8
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

45. 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

46. 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

47. 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 3.634
Banana, ad libitum (mg/d) 0.162 0.182
Tracer and unenriched zinc (mg/d) 1.014 1.000
Total 3.816 4.816
Estimated P:Z molar ratio 27 25
Results

48. 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

49. 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

50. 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?

51. Kenneth H Brown, Leslie R Woodhouse. UC Davis, WHNRC
Bakhtiar Hossain, Tahmeed Ahmed, Nazmul Huda, Tanveer
Ahmed. ICDDR,B
Christine Hotz, Erick Boy. HarvestPlus
Co-Investigators
Agencies and technical partners
HarvestPlus Challenge Program, HarvestPlus
International Atomic Energy Agency (IAEA), Vienna, Austria
Bangladesh Rice Research Institute (BRRI)
ICDDR, B staff and Residents of the community
Acknowledgments

52. Research
Team

53. Thank you