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Nutrition intervention strategies to combat zinc deficiency in developing countries

Published online by Cambridge University Press:  14 December 2007

Rosalind S. Gibson  and
Elaine L. Ferguson
Rosalind S. Gibson
Affiliation:
Department of Human Nutrition, University of Otago, Dunedin, New Zealand
Elaine L. Ferguson
Affiliation:
Department of Human Nutrition, University of Otago, Dunedin, New Zealand
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Abstract

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Widespread zinc deficiency is likely to exist in developing countries where staple diets are predominantly plant based and intakes of animal tissues are low. The severe negative consequences of zinc deficiency on human health in developing countries, however, have only recently been recognized. An integrated approach employing targeted supplementation, fortification and dietary strategies must be used to maximize the likelihood of eliminating zinc deficiency at a national level in developing countries. Supplementation is appropriate only for populations whose zinc status must be improved over a relatively short time period, and when requirements cannot be met from habitual dietary sources. As well, the health system must be capable of providing consistent supply, distribution, delivery and consumption of the zinc supplement to the targeted groups. Uncertainties still exist about the type, frequency, and level of supplemental zinc required for prevention and treatment of zinc deficiency. Salts that are readily absorbed and at levels that will not induce antagonistic nutrient interactions must be used. At a national level, fortification with multiple micronutrients could be a cost effective method for improving micronutrient status, including zinc, provided that a suitable food vehicle which is centrally processed is available. Alternatively, fortification could be targeted for certain high risk groups (e.g. complementary foods for infants). Efforts should be made to develop protected fortificants for zinc, so that potent inhibitors of zinc absorption (e.g. phytate) present either in the food vehicle and/or indigenous meals do not compromise zinc absorption. Fortification does not require any changes in the existing food beliefs and practices for the consumer and, unlike supplementation, does not impose a burden on the health sector. A quality assurance programme is required, however, to ensure the quality of the fortified food product from production to consumption. In the future, dietary modification/diversification, although long term, may be the preferred strategy because it is more sustainable, economically feasible, culturally acceptable, and equitable, and can be used to alleviate several micronutrient deficiencies simultaneously, without danger of inducing antagonistic micronutrient interactions. Appropriate dietary strategies include consumption of zinc-dense foods and those known to enhance zinc absorption, reducing the phytic acid content of plant based staples via enzymic hydrolysis induced by germination/fermentation or nonenzymic hydrolysis by soaking or thermal processing. All the strategies outlined above should be integrated with ongoing national food, nutrition and health education programmes, to enhance their effectiveness and sustainability, and implemented using nutrition education and social marketing techniques. Ultimately the success of any approach for combating zinc deficiency depends on strong advocacy, top level commitment, a stable infrastructure, long term financial support and the capacity to control quality and monitor and enforce compliance at the national or regional level. To be cost effective, costs for these strategies must be shared by industry, government, donors and consumers.

Type
Research Article
Information
Nutrition Research Reviews , Volume 11 , Issue 1 , June 1998 , pp. 115 - 131
Copyright
Copyright © The Nutrition Society 1998

References

Aggett, P. J. & Comerford, J. G. (1995). Zinc and human health. Nutrition Reviews 53, S16–S22.Google ScholarPubMed
Amoa, B. & Muller, H.G. (1975). Studies on Kenkey with particular reference to calcium and phytic acid. Cereal Chemistry 53, 365–375.Google Scholar
Barrie, S. A., Wright, J. V., Pizzorno, J. E., Kutter, E. & Barron, P. C. (1987). Comparative absorption of zinc picolinate, zinc citrate, and zinc gluconate in humans. Agents and Actions 21, 223–228.CrossRefGoogle ScholarPubMed
Bates, C. J., Evans, P. H., Dardenne, M., Prentice, A., Lunn, P. G., Northrop-Clewes, C. A., Hoare, S., Cole, T. J., Horan, S. J., Longman, S. C., Stirling, D. & Aggett, P. J. (1993). A trial of zinc supplementation in young rural Gambian children. British Journal of Nutrition 69, 243–255.CrossRefGoogle ScholarPubMed
Beaton, G. H. (1995). Fortification of Foods for Refugee Feeding; Final Report. Hull, QC, Canada: Canadian International Development Agency (CIDA).Google Scholar
Black, M. R., Medeiros, D. M., Brunett, E. & Welke, R. (1988). Zinc supplements and serum lipids in young adult white males. American Journal of Clinical Nutrition 47, 970–975.CrossRefGoogle ScholarPubMed
Bressani, R. (1972). The importance of maize for human nutrition in Latin America and other countries. In Nutritional Improvement of Maize (INCAP publication L-4), pp. 5–29. Guatemala: INCAP.Google Scholar
Brown, K., Dewey, K. G. & Allen, L. H. (1997). Complementary feeding of young children in developing countries, a review of scientific knowledge (In Press).Google Scholar
Cavan, K. R., Gibson, R. S., Grazioso, C. F., Isalgue, A. M., Ruz, M. & Solomons, N. W. (1993). Growth and body composition of periurban Guatemalan children in relation to zinc status: a cross-sectional study. American Journal of Clinical Nutrition 57, 334–343.CrossRefGoogle ScholarPubMed
Chandra, R.K. (1984). Excessive intake of zinc impairs immune responses. JAMA (Journal of the American Medical Association) 252, 1443–1446.CrossRefGoogle ScholarPubMed
Chang, R., Schwimmer, S. & Burr, H. K. (1977). Phytate: removal from whole dry beans by enzymatic hydrolysis and diffusion. Journal of Food Science 42, 1098–1101.CrossRefGoogle Scholar
Chavan, J. K. & Kadam, S. S. (1989). Nutritional improvement of cereals by fermentation. Critical Reviews in Food Science and Nutrition 28, 349–400.CrossRefGoogle ScholarPubMed
Cheryan, M. (1980). Phytic acid interactions in food systems. Critical Reviews in Food Science and Nutrition 13, 297–335.CrossRefGoogle ScholarPubMed
Combs, G. R., Dexter, P. B., Horton, S. E. & Buescher, R. (1994). Micronutrient Fortification and Enrichment of P.L. 480 Title II Commodities: Recommendations for Improvement. A Technical Review Paper. Opportunities for Micronutrient Interventions.Google Scholar
CEC (1994). Reference Nutrient Intakes for the European Community (CS/RDA 15). Brussels: Commission of the European Communities. Scientific Committee for Food (III/C/I).Google Scholar
COMA (Committee on Medical Aspects of Food Policy) (1991). Dietary Reference Values for Food Energy and Nutrients for the United Kingdom; Report on Health and Social Subjects 41. London: HMSO.Google Scholar
Cook, J. D., Dassenko, S. A. & Whittaker, P. (1991). Calcium supplementation: effect on iron absorption. American Journal of Clinical Nutrition 53, 106–111.CrossRefGoogle ScholarPubMed
Crofton, R. W., Gvozdanovic, D., Gvozdanovic, S, Khin, C. C., Brunt, P. W., Mowat, N. A. G. & Aggett, P. J. (1989). Inorganic zinc and the intestinal absorption of ferrous iron. American Journal of Clinical Nutrition 50, 141–144.CrossRefGoogle ScholarPubMed
Davidsson, L., Kastenmayer, P. & Hurrell, R. F. (1994). Sodium iron EDTA [NaFe (III) EDTA] as a food fortificant: the effect on the absorption and retention of zinc and calcium in women. American Journal of Clinical Nutrition 60, 231–237.CrossRefGoogle ScholarPubMed
De Boland, A. R, Garner, G. B. & O'Dell, B. L. (1975). Identification and properties of “phytate” in cereal grains and oil-seed products. Journal of Agricultural and Food Chemistry 23, 1186–1189.CrossRefGoogle Scholar
Desrosiers, T., & Clydesdale, F.M. (1989). Effectiveness of organic chelators in solubilizing calcium and zinc in fortified cereals under simulated gastrointestinal pH conditions. Journal of Food Processing and Preservation 13, 307–319.CrossRefGoogle Scholar
Fischer, P. W. F., Giroux, A. & L'Abbé, M. R. (1984). Effect of zinc supplementation on copper status in adult men. American Journal of Clinical Nutrition 40, 743–746.CrossRefGoogle Scholar
FitzGerald, S. (1997). Fortification Rapid Assessment Guidelines & Tool (FRAT). Ottawa: Path Canada.Google Scholar
FAO/WHO (1988). Requirements of Vitamin A, Iron, Folate and Vitamin B12; FAO Nutrition Series No. 23. Rome: Food and Agricultural Organization of the United Nations.Google Scholar
FAO/WHO (1993). Joint FAO/WHO Expert Committee on Food Additives 41st report; WHO Technical Report Series 837. Geneva: World Health Organization.Google Scholar
Fosmire, G. J. (1990). Zinc toxicity. American Journal of Clinical Nutrition 51, 225–227.CrossRefGoogle ScholarPubMed
Freeland-Graves, J. H., Friedman, B. J., Han, W.-H., Shorey, R. L. & Young, R. (1982). Effect of zinc supplementation on plasma high-density lipoprotein cholesterol and zinc. American Journal of Clinical Nutrition 35, 988–992.CrossRefGoogle ScholarPubMed
Galloway, R. & McGuire, J. (1994). Determinants of compliance with iron supplementation: supplies, side effects, and psychology? Social Science & Medicine 39, 381–390.CrossRefGoogle Scholar
Gibson, R. S. (1994). Zinc nutrition in developing countries. Nutrition Research Reviews 7, 151–173.CrossRefGoogle ScholarPubMed
Gibson, R. S., Koepf, J., Bettger, W. J., Lehrfeld, J. & Ferguson, E. L. (1997). Dietary strategies to combat trace mineral deficiencies in weanlings from Subsaharan Africa. In Proceedings of the Ninth International Symposium on Trace Elements in Man and Animals, pp. 451–454 [Fischer, P.W.F., L'Abbé, M.R.L., Cockell, K.A. and Gibson, R.S., editors]. Ottawa: NRC Research Press.Google Scholar
Gibson, R. S., Smit Vanderkooy, P. D., MacDonald, A. C., Goldman, A., Ryan, B. A & Berry, M. 1989. A growth-limiting, mild zinc-deficiency syndrome in some Southern Ontario boys with low height percentiles. American Journal of Clinical Nutrition 49, 1266–1273.CrossRefGoogle ScholarPubMed
Gillespie, S., Kevany, J. & Mason, J. (1991). Controlling Iron Deficiency; ACC/SCN State-of-the-Art Series Nutrition Policy Discussion Paper No. 9. Geneva: United Nations Administrative Committee on Coordination/Subcommittee on Nutrition.Google Scholar
Golden, M. H. N., Briend, A. & Grellety, Y. (1995). Meeting Report: Report of meeting on supplementary feeding prgrammes with particular reference to refugee populations. European Journal of Clinical Nutrition 49, 137–145.Google Scholar
Goldenberg, R. L., Tamura, T., Neggers, Y., Copper, R. L., Johnston, K., DuBard, M. B. & Hauth, J. C. (1995). The effect of zinc supplementation on pregnancy outcome. JAMA (Journal of the American Medical Association) 274, 463–468.CrossRefGoogle ScholarPubMed
Gopaldas, T., Mehta, P., Patil, A. & Gandhi, H. (1986). Studies on reduction in viscosity of thick rice gruels with small quantities of an amylase-rich cereal malt. Food and Nutrition Bulletin 8, 42–47.CrossRefGoogle Scholar
Graham, R. D., Ascher, J. S. & Hynes, S. C. (1992). Selecting zinc-efficient cereal genotypes for soils of low zinc status. Plant and Soil 146, 241–250.CrossRefGoogle Scholar
Hallberg, L. (1992). Iron balance in pregnancy and lactation. In Nutritional Anaemias, Nestlé Nutrition Workshop Series 30, pp. 13–28 [Fomon, A. J., and Zlotkin, S., editors]. Vevey: Nestlé Ltd.Google Scholar
Hambidge, K. M. (1997). Zinc deficiency in young children. American Journal of Clinical Nutrition 65, 160–161.CrossRefGoogle ScholarPubMed
Henderson, L. M., Brewer, G. J., Dressman, J. B., Swidan, S. Z., DuRoss, D. J., Adair, C. H., Barnett, J. L. & Berardi, R. R. (1995). Effect of intragastric pH on the absorption of oral zinc acetate and zinc oxide in young healthy volunteers. Journal of Parenteral and Enteral Nutrition 19, 393–397.CrossRefGoogle ScholarPubMed
Hooper, P. L., Visconti, L., Garry, P. J. & Johnson, G. E. (1980). Zinc lowers high-density lipoprotein-cholesterol levels. Journal of the American Medical Association 244, 1960–1961.CrossRefGoogle ScholarPubMed
House, W. A., Van Campen, D. R. & Welch, R. M. (1996). Influence of dietary sulfur-containing amino acids on the bioavailability to rats of zinc in corn kernels. Nutrition Research 16, 225–235.CrossRefGoogle Scholar
Hurrell, R. F. (1997). Preventing iron deficiency through food fortification. Nutrition Reviews 55, 210–222.CrossRefGoogle ScholarPubMed
INACG (1993). Iron EDTA for Food Fortification; a Report of the International Nutritional Anemia Consultative Group. Washington, DC: The Nutrition Foundation/ILSI.Google Scholar
ISGPD (International Study Group on Persistent Diarrhea) (1996). Evaluation of an algorithm for the treatment of diarrhea: a multi-centre study. Bulletin of the World Health Organization 74, 479–488.Google Scholar
Lehrfeld, J. (1989). High-performance liquid chromatography analysis of phytic acid on a pH-stable, macroporous polymer column. Cereal Chemistry 66, 510–515.Google Scholar
Lolas, G.M. & Markakis, P. (1977). The phytase content of navy beans (Phaseolus vulgaris). Journal of Food Science 42, 1094–1097.CrossRefGoogle Scholar
Lönnerdal, B., Sandberg, A-S., Sandström, B. & Kunz, C. (1989). Inhibitory effects of phytic acid and other inositol phosphates on zinc and calcium absorption in suckling rats. Journal of Nutrition 119, 211–214.CrossRefGoogle ScholarPubMed
Lorenz, K. (1980). Cereal sprouts: composition, nutritive value, food applications. Critical Reviews in Food Science and Nutrition 13, 353–385.CrossRefGoogle ScholarPubMed
Lotfi, M., Mannar, V., Merx, R. J. H. M. & Naber-van den Heuvel, P. (1996). Micronutrient Fortification of Foods. Current Practices, Research, and Opportunities. The Micronutrient Initiative, c/o International Development Research Centre/International Agriculture Centre.Google Scholar
Mensah, P. P. A., Drasar, B. S., Harrison, T. J. & Tomkins, A. M. (1991). Fermented cereal gruels: towards a solution of the weanling's dilemma. Food and Nutrition Bulletin 13, 50–57.CrossRefGoogle Scholar
Momciloviç, B. (1995). Coupling of zinc dose to frequency in a regularly recurrent pattern shows a limited capacity of excessive dietary zinc to compensate for a previously deficient intake. Journal of Nutrition 125, 2687–2699.Google Scholar
Mosha, A. C. & Svanberg, U. (1990). The acceptance and intake of bulk-reduced weaning foods: the Luganga village study. Food and Nutrition Bulletin 12, 69–74.CrossRefGoogle Scholar
NAS (National Academy of Sciences). (1991). Nutrition during Lactation. Washington, DC: National Academy Press.Google Scholar
Nout, M. J. R. (1993). Processed weaning foods for tropical climates. International Journal of Food Sciences and Nutrition 43, 213–221.CrossRefGoogle Scholar
O'Dell, B. L., de Bowland, A. R. & Koirtyohann, S. R. (1972). Distribution of phytate and nutritionally important elements among the morphological components of cereal grains. Journal of Agricultural and Food Chemistry 20, 718–721.CrossRefGoogle Scholar
Oelshlegel, F. J. & Brewer, G. J. (1977). Absorption of pharmacological doses of zinc. In Zinc Metabolism: Current Aspects in Health and Disease, pp. 299–316 [Brewer, G.J. and Prasad, A.S. editors]. New York: Alan R. Liss.Google Scholar
Prasad, A. S., Beck, F. W. J. & Nowak, J. (1993). Comparison of absorption of five zinc preparations in humans using oral zinc tolerance test. Journal of Trace Elements and Electrolytes in Health and Disease 6, 109–115.Google Scholar
Prasad, A. S., Brewer, G. J., Schoomaker, E. B. & Rabbani, P. (1978). Hypocupremia induced by zinc therapy in adults. Journal of the American Medical Association 240, 2166–2168.CrossRefGoogle ScholarPubMed
Prasad, A. S., Miale, A., Farid, Z., Sandstead, H. H. & Schulert, A. R. (1963). Zinc metabolism in patients with syndrome of iron deficiency anemia, hepatosplenomegaly, dwarfism, and hypogonadism. Journal of Laboratory and Clinical Medicine 61, 537–549.Google Scholar
Rosado, J. L., López, P., Muñoz, E., Martinez, H. & Allen, L. H. (1997). Zinc supplementation reduced morbidity, but neither zinc nor iron supplementation affected growth or body composition of Mexican preschoolers. American Journal of Clinical Nutrition 65, 13–19.CrossRefGoogle ScholarPubMed
Rosado, J. L., Muñoz, E., López, P. & Allen, L. H. (1993). Absorption of zinc sulfate, methionine, and polyascorbate in the presence and absence of a plant-based rural Mexican diet. Nutrition Research 13, 1141–1151.CrossRefGoogle Scholar
Roy, S. K., Behrens, R. H., Haider, R., Akramuzzaman, S. M., Mahalanabis, D., Wahed, M. A. & Tomkins, A. M. (1992). Impact of zinc supplementation on intestinal permeability in Bangladeshi children with acute diarrhoea and persistent diarrhoea syndrome. Journal of Pediatric Gastroenterology and Nutrition 15, 289–296.Google ScholarPubMed
Sachdev, H. P. S., Mittal, N. K & Yadav, H. S. (1990). Oral zinc supplementation in persistent diarrhoea in infants. Annals of Tropical Paediatrics 10, 63–69.CrossRefGoogle ScholarPubMed
Sandberg, A-S. & Andersson, H. (1988). Effect of dietary phytase on the digestion of phytate in the stomach and small intestine of humans. Journal of Nutrition 118, 469–473.CrossRefGoogle ScholarPubMed
Sandberg, A-S, Rossander Hulthen, L. & Turk, M. (1996). Dietary Aspergillus niger phytase increases iron absorption in humans. Journal of Nutrition 126, 476–480.CrossRefGoogle ScholarPubMed
Sandström, B., Almgren, A., Kivistö, B. & Cederblad, Å. (1989). Effect of protein level and protein source on zinc absorption in humans. Journal of Nutrition 119, 48–53.CrossRefGoogle ScholarPubMed
Sandström, B., Arvidsson, B., Cederblad, Å. & Björn-Rasmussen, E. (1980). Zinc absorption from composite meals. 1. The significance of wheat extraction rate, zinc, calcium, and protein content in meals based on bread. American Journal of Clinical Nutrition 33, 739–745.CrossRefGoogle Scholar
Sandström, B., Davidson, L., Cederblad, Å. & Lönnerdal, B. (1985). Oral iron, dietary ligands and zinc absorption. Journal of Nutrition 115, 411–414.CrossRefGoogle ScholarPubMed
Sazawal, S., Black, R. E., Bhan, M. K., Bhandari, N., Sinha, A. & Jalla, S. (1995). Zinc supplementation in young children with acute diarrhea in India. New England Journal of Medicine 333, 839–844.CrossRefGoogle ScholarPubMed
Schölmerich, J., Freudemann, A., Köttgen, E., Wietholz, H., Steiert, B., Löhle, B., Häussinger, D. & Gerok, W. (1987). Bioavailability of zinc from zinc-histidine complexes. 1. Comparison with zinc sulfate in healthy men. American Journal of Clinical Nutrition 45, 1480–1486.CrossRefGoogle ScholarPubMed
Scott, M. L. & Zeigler, T. R. (1963). Evidence for natural chelates which aid in the utilization of zinc by chicks. Journal of Agricultural and Food Chemistry 11, 123–125.CrossRefGoogle Scholar
Smith, C. J. (1994). Comparison of reference dose with recommended dietary allowances for zinc: methodologies and levels. In Risk Assessment of Essential Elements, pp. 127–143 [Mertz, W., Abernathy, C. O. and Olin, S. S., editors]. Washington, DC: ILSI Press.Google Scholar
Snedeker, S. M. & Greger, J. L. (1983). Metabolism of zinc, copper, and iron as affected by dietary protein, cysteine and histidine. Journal of Nutrition 113, 644–652.CrossRefGoogle ScholarPubMed
Solomons, N. W. (1986). Competitive interaction of iron and zinc in the diet: consequences for human nutrition. Journal of Nutrition 116, 927–935.CrossRefGoogle ScholarPubMed
Stoltzfus, R. J., Dreyfuss, M. L., Chwaya, H. M. & Albonico, M. (1997). Hookworm control as a strategy to prevent iron deficiency. Nutrition Reviews 55, 223–232.CrossRefGoogle ScholarPubMed
Sturniolo, G. C., Montino, C., Rossetto, L., Martin, A., D'Inca, R., D'Odorico, A. & Naccarato, R. (1991). Inhibition of gastric acid secretion reduces zinc absorption in man. Journal of the American College of Nutrition 10, 372–375.CrossRefGoogle ScholarPubMed
Svanberg, U. & Sandberg, A-S. (1988). Improved iron availability in weaning foods through the use of germination and fermentation. In Improving Young Child Feeding in Eastern and Southern Africa; Household Level Food Technology, pp. 366–373 [Alnwick, D. Moses, S. and Schmidt, O.G., editors]. Nairobi: International Development Research Center.Google Scholar
Svanberg, U., Lorri, W. & Sandberg, A-S. (1993). Lactic fermentation of non-tannin and high-tannin cereals: effects on in vitro estimation of iron availability and phytate hydrolysis. Journal of Food Science 58, 408–412.CrossRefGoogle Scholar
Swanson, C. A. & King, J. C. (1987). Zinc and pregnancy outcome. American Journal of Clinical Nutrition 46, 763–771.CrossRefGoogle ScholarPubMed
Tabekhia, M. M. & Luh, B. S. (1980). Effect of germination, cooking, and canning on phosphorus and phytate retention in dry beans. Journal of Food Science 45, 406–408.CrossRefGoogle Scholar
Tamura, T. & Goldenberg, R. L. (1996). Zinc nutriture and pregnancy outcome. Nutrition Research 16, 139–181.CrossRefGoogle Scholar
Tomkins, A., Behrens, R. & Roy, S. (1993). The role of zinc and vitamin A deficiency in diarrhoeal syndromes in developing countries. Proceedings of the Nutrition Society 52, 131–142.CrossRefGoogle ScholarPubMed
Turk, M. & Sandberg, A.-S. (1992). Phytate degradation during breadmaking: effect of phytase addition. Journal of Cereal Science 15, 281–294.CrossRefGoogle Scholar
Udomkesmalee, E., Dhanamitta, S., Yhoung-Aree, J., Rojroongwasinkul, N. & Smith, J. C. (1990). Biochemical evidence suggestive of suboptimal zinc and vitamin A status in schoolchildren in Northeast Thailand. American Journal of Clinical Nutrition 52, 564–567.CrossRefGoogle ScholarPubMed
U.S. EPA (Environmental Protection Agency) (1992). Reference dose (Rfd): description and use in health risk assessments, IRIS, online. Cincinnati, OH: Environmental Criteria and Assessment Office,.Google Scholar
United Nations (1991). Some options for improving nutrition in the 1990s. SCN News no. 7, Suppl. 16–18.Google Scholar
Valberg, L. S., Flanagan, P. R. & Chamberlain, M. J. (1984). Effects of iron, tin and copper on zinc absorption in humans. American Journal of Clinical Nutrition 40, 536–541.CrossRefGoogle ScholarPubMed
Viteri, F. E., Alvarez, E., Batres, R., Torún, B., Pineda, O., Mejía, L. A. & Sylvi, J. (1995). Fortification of sugar with iron sodium ethylenedaminotetraacetate (FeNaEDTA) improves iron status in semirural Guatemalan populations. American Journal of Clinical Nutrition 61, 1153–1163.CrossRefGoogle ScholarPubMed
Walsh, C. T., Sandstead, H. H., Prasad, A. S., Newberne, P. M. & Fraker, P. J. (1994). Zinc: health effects and research priorities for the 1990s. Environmental Health Perspectives 102 (Suppl. 2), 5–46.Google ScholarPubMed
Wedekind, K. J. & Baker, D. H. (1990). Zinc bioavailability in feed-grade sources of zinc. Journal of Animal Science 68, 684–689.CrossRefGoogle ScholarPubMed
Williams, G. & Naraqi, S. (1979). Severe anaemia in Port Moresby. A review of 101 adult melanesian patients with haemoglobin level of 4g/100ml or less. Papua New Guinea Medical Journal 22, 129–136.Google ScholarPubMed
Wolfe, S. A., Gibson, R. S., Gadowsky, S. L. & O'Connor, D. L. (1994). Zinc status of a group of pregnant adolescents at 36-weeks gestation living in Southern Ontario. Journal of the American College of Nutrition 13, 154–164.CrossRefGoogle ScholarPubMed
Wood, R. J. & Zheng, J. J. (1997). High dietary calcium intakes reduce zinc absorption and balance in humans. American Journal of Clinical Nutrition 65, 1803–1809.CrossRefGoogle ScholarPubMed
WHO (1996). Trace Elements in Human Nutrition and Health. Geneva: World Health Organization.Google Scholar
Xu, P., Price, J. & Aggett, P. J. (1992). Recent advances in methodology for analysis of phytate and inositol phosphates in foods. Progress in Food and Nutrition Science 16, 245–262.Google ScholarPubMed
Yadrick, M. K., Kenney, M. A & Winterfeldt, E. A. (1989). Iron, copper and zinc status: response to supplementation with zinc or zinc and iron in adult females. American Journal of Clinical Nutrition 49, 145–150.CrossRefGoogle ScholarPubMed