other bio-fortification example – high zinc rice

Zinc Biofortification of Rice in Bangladesh

Dr M Munirul Islam, MBBS, PhD

Associate Scientist, Centre for Nutrition & Food SecurityConsultant Physician, Clinical Nutrition Unit

[email protected]

International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR, B)

In collaboration withUniversity of California, Davis and HarvestPlus

mailto:[email protected]

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?




Prevalence stunting, children <5 yr 43%(BDHS, 2007)






Prevalence low serum zinc conc. (<65 µg/dL)

45% infants (Baqui, 2005)59% children (Kongsbak, 2006)






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)


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


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)


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


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


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


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


Admit to study ward

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



2. Diet-CR + 70Zn


1. Diet-CR + 70ZnOR

2. Diet-ZnBfR + 67Zn

Admit to study ward

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



2. Diet-CR + 70Zn


1. Diet-CR + 70ZnOR


Admit to study ward

IV 68Zn infusion, 4 hours after dinner

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



2. Diet-CR + 70Zn


1. Diet-CR + 70ZnOR


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


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

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)


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


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

other bio-fortification example – high zinc rice

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