Zinc fortification of cereal flours: current recommendations and research needs

2. Zinc fortification of cereal flours:current recommendations and research needs Zinc Working Group Kenneth H Brown, K Michael Hambidge, Peter Ranum, Vilma Tyler, Robert E Black, Quentin Johnson (Ibrahim Parvanta, Omar Dary) Second Technical Workshop on Flour Fortification, Atlanta, GA; March 30-April 3, 2008

3. Overview of presentation Background Zinc and human health Assessment of population zinc status Epidemiology of zinc deficiency Impact of zinc fortification Tracer studies Efficacy trials Effectiveness trial Appropriate levels and forms of zinc fortification Simulations of effects on TAZ Upper levels of fortification Chemical form of zinc Potential adverse effects Sensory trials Mineral absorption Summary of recommendations Research needs

4. Zinc and human health Multiple zinc-containing enzymes with broad range of physiological effects Required for normal immune function, physical growth, pregnancy outcome Deficiency results in increased diarrhea, pneumonia, and possibly malaria and other infections; reduced weight gain and linear growth

5. Global deaths and disability-adjusted life-years (DALY)among children <5 yrs attributed to MN deficiencies

6. Assessment of population zinc status New recommendations by WHO / UNICEF / IAEA / IZiNCG: Serum zinc concentration:  best biomarker Dietary assessment:  risk of inadequate intake,  identification of vehicles for fortification Childhood stunting:  best functional indicator

8. Global prevalence of zinc deficiency Little information available based on biomarkers of zinc status Current estimates based of prevalence of child stunting Assessments should be added to all planned nutritional status surveys in countries with an elevated risk of zinc deficiency!

10. Current status of zinc fortification programs 4 countries require zinc fortification, and 9 countries include zinc in voluntary fortification guidelines for wheat flour 5 countries proposing new programs that would include zinc 4 countries include zinc in maize flour fortification standards Current fortification standards range from 14 to 33 ppm All countries use zinc oxide Current cost of zinc (as zinc oxide) is ~$0.25/MT to fortify at level of 30 mg zinc/kg flour

11. FAZ and total absorbed zinc by amount of zinc intake from fortified foods

12. Effect of zinc fortificationon total absorbed zinc (TAZ)

13. Conflicting evidence of effect on serum zinc concentration in young children and schoolchildren, possibly related to age, vehicle, and dose

14. Impact of zinc fortification of wheat flour* on mean serum zinc conc (China)

15. The roles of zinc transporters in maintainingintracellular zinc concentration

16. Quantity of Zinc Absorbed: Saturation Response Model

19. Selected prediction curves for constant dietary phytate

24. I used the same graph for all four slides so the lines and numbers would not move. This is about as good as I can get it (with the time I want to spend). The jumps between movements is very slight. You can play with the speed of the movement later. I set the color of the lines so they won't change with new color schemes but the curves are not a set color. The only irritation is that you have to go back and remove the lines around the text (numbers) after changing the line colors. I did not group the text boxes (other than the numbers) to the rest. So you have the background, the graph box, the curve and the text legends in separate sets. Do NOT group the curve to the rest or you'll lose the animation. If you want the whole graph shorter, move the curve out of the way, ungroup the graph, shorten each line then shorten the background, then regroup the graph and move the curve back on. This will not mess up the sideways movement of the curve as long as you start the curve back on the center/medianI used the same graph for all four slides so the lines and numbers would not move. This is about as good as I can get it (with the time I want to spend). The jumps between movements is very slight. You can play with the speed of the movement later. I set the color of the lines so they won't change with new color schemes but the curves are not a set color. The only irritation is that you have to go back and remove the lines around the text (numbers) after changing the line colors. I did not group the text boxes (other than the numbers) to the rest. So you have the background, the graph box, the curve and the text legends in separate sets. Do NOT group the curve to the rest or you'll lose the animation. If you want the whole graph shorter, move the curve out of the way, ungroup the graph, shorten each line then shorten the background, then regroup the graph and move the curve back on. This will not mess up the sideways movement of the curve as long as you start the curve back on the center/median

25. Simulations of effects of zinc fortification Flour intakes from 50-800 g/d Zinc and phytate contents of 80% and 95% extraction wheat flour (courtesy of H+) Assumed Zn and phytate intakes from non-wheat sources Level of zinc fortification “TAZ UL”

26. Recommended level of zinc fortification of wheat flour (mg/kg), by amount of flour intake (80% extraction)*

27. Recommended level of zinc fortification of wheat flour (mg/kg), by amount of flour intake (95% extraction)*

28. Effect of differences in zinc and phytate intake from other sources on recommended level of zinc fortification, 80% extraction

31. Zinc fortificant compounds

32. Fractional absorption of zinc (FAZ) from foods fortified with ZnO or ZnSO4

33. Potential adverse effects of zinc fortificants Absorption of other minerals Sensory properties

34. Effect of zinc fortification on sensory properties of bread Ranhotra GS (Cereal Chem 54:496, 1977): Leavened bread prepared with or without 22 mg Zn/kg, as oxide, sulfate, stearate, or acetate) No effect on bread quality Khalil MM (Nahrung/Food 6:389, 2002): Leavened bread prepared with or without 1000 mg Zn/kg, as Zn sulfate* No differences in crust color, crumb color, crumb texture, flavor, or overall quality

35. Effect of zinc fortification on sensory properties of wheat products Bread and noodles prepared from flour fortified with 60 or 90 mg zinc/kg flour, as either zinc oxide or zinc sulfate Flavor, texture and overall degree of liking (DOL) evaluated with 9-point hedonic scale (adult volunteers) No difference in DOL of breads; small differences with noodles

36. Effect of zinc fortification on sensory properties of wheat noodles

37. Mean consumption of cereal porridge,by study group

38. Conclusions

39. Conclusions

40. Conclusions, continued Implies need for information on usual dietary intakes of cereal flours, zinc, and phytate by individuals Best practices working group(s) for assessing dietary intake and nutritional impact in the context of food fortification programs

41. Tables of recommended levels of fortification*

42. Tables of recommended levels of fortification

43. Potential impact of flour fortification on young children

45. Research needs Prediction model for zinc absorption in young children, and expansion of range of existing model for adults Reassessment of EAR & UL, adjusting for dietary phytate (flour extraction) Efficacy and effectiveness of zinc fortification programs in high risk sub-groups of population (children, adolescents, PLW, elderly) Possible roles of enhancers of zinc absorption (phytase, EDTA) Evaluation of potential indicators of individual and population zinc status and impact of zinc fortification programs

46. Discussion points Available data on dietary zinc and phytate intakes, levels of wheat flour extraction and zinc and phytate contents, by region Review recommendations for levels of fortification Zinc, phytate composition of maize Selection of countries for zinc fortification Establish “technical UL” Impact evaluation Indicators Population segment(s) Timing