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Other Bio-fortification example – High Zinc Rice

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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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Other Bio-fortification example – High Zinc Rice

  1. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 21. Will increased zinc intake improve zinc status and health outcomes?
  22. 22. Absorption of zinc from mixed diets containing conventional or zinc-biofortified Bangladeshi rice among young children in a peri-urban community
  23. 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. 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. 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. 26. Subject recruiting site: Nandipara 10 km away from Centre
  27. 27. Rice samples Zinc Biofortified Rice (ZnBfR) Conventional Rice (CR)
  28. 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. 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. 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. 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. 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. 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. 34. Diet Preparation
  35. 35. Feeding
  36. 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. 37. Methods Tracer protocol for zinc absorption studies: Administration of oral isotope
  38. 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. 39. Methods Tracer protocol for zinc absorption studies: Administration of intra-venous isotope
  40. 40. Methods Tracer protocol for zinc absorption studies: Administration of intra-venous isotope
  41. 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. 42. Methods Urine sample processing
  43. 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. 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. 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. 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. 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. 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. 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. 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. 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. 52. Research Team
  53. 53. Thank you

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