Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-23T08:22:00.227Z Has data issue: false hasContentIssue false
  • English
  • Français

Selenium and iodine intakes and status in New Zealand and Australia

Published online by Cambridge University Press:  09 March 2007

Christine D. Thomson
Christine D. Thomson*
Affiliation:
Department of Human Nutrition, University of Otago, Dunedin, New Zealand
*
*Corresponding author: Professor C. D. Thomson, fax +64 3 479 7958, email [email protected]
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Most New Zealand soils contain relatively low concentrations of the anionic trace elements F, I and Se. Some areas of Australia also have a history of I deficiency. In view of current interest in establishing nutrient reference intakes for Se and I in New Zealand and Australia, it is timely to review current understanding of the intakes and status of these two elements. In spite of a recent increase in Se status, the status of New Zealanders remains low compared with populations of many other countries and may still be considered marginal, although the clinical consequences of the marginal Se status are unclear. There are no recent reports of blood Se levels in Australia, but earlier reports indicate that they were generally greater than those of New Zealanders. Similarly, the consequences of decreasing I status in Australia and New Zealand are unclear. Mild I deficiency in New Zealand has resulted in enlarged thyroid glands indicating an increased risk of goitre. Currently there is little evidence, however, of any associated clinical disease. Public health recommendations to reduce salt intake, together with the reduction in I content of dairy products, are likely to result in further decreases in the I status of New Zealand and Australian residents. Some action is needed to prevent this decline and it may be necessary to consider other means of fortification than iodized salt. The consequences of possible interactions between Se and I in human nutrition are also unclear and no practical recommendations can be made.

Keywords

SeleniumIodineSelenium statusIodine statusNew ZealandAustralia
Type
Review article
Information
British Journal of Nutrition , Volume 91 , Issue 5 , May 2004 , pp. 661 - 672
Copyright
Copyright © The Nutrition Society 2004

References

Arthur, JR (1999) Functional indicators of iodine and selenium status. Proc Nutr Soc 58, 507–512.Google ScholarPubMed
Arthur, JR, Nicol, F, Rae, PWH & Beckett, GJ (1990) Effects of combined selenium and iodine deficiencies on the thyroid gland of the rat. J Endocrinol 124, Suppl.240.Google Scholar
Barceloux, DG (1999) Selenium. Clin Toxicol 37, 145–172.Google ScholarPubMed
Beckett, GJ, Nicol, F, Rae, PWH, Beech, S, Guo, Y & Arthur, JR (1993) Effects of combined iodine deficiency and selenium deficiency on thyroid hormone metabolism in rats. Am J Clin Nutr 57, 240S–243S.CrossRefGoogle ScholarPubMed
Bull, NL & Buss, DH (1980) Contributions of food to sodium intakes. Proc Nutr Soc 39, 30A.Google ScholarPubMed
Burk, RF & Levander, OA (1999) Selenium. In Modern Nutrition in Health and Disease, pp. 265–276 [Shils, ME, Olson, JA, Shike, M and Ross, AC, editors]. Baltimore, MD: Williams & Wilkins.Google Scholar
Clements, FW & Wishart, JW (1956) A thyroid-blocking agent in the etiology of endemic goiter. Metabolism 5, 623–639.Google ScholarPubMed
Colls, AJ (1996) Iodine and selenium status of Dunedin blood donors, MSc Thesis, University of Otago.Google Scholar
Combs, GF Jr (2001) Selenium in global food systems. Br J Nutr 85, 517–547.CrossRefGoogle ScholarPubMed
Connolly, RJ (1971) The changing iodine environment of Tasmania. Med J Aust 2, 1191–1193.CrossRefGoogle ScholarPubMed
Contempré, B, Dumont, JE, Ngo, B, Thilly, CH, Diplock, AT & Vanderpas, J (1991a) Effect of selenium supplementation in hypothyroid subjects of an iodine and selenium deficient area: the possible danger of indiscriminate supplementation of iodine-deficient subjects with selenium. J Clin Endocrinol Metab 73, 213–215.CrossRefGoogle ScholarPubMed
Contempré, B, Vanderpas, J & Dumont, J (1991b) Cretinism, thyroid hormones and selenium. Mol Cell Endocrinol 81, C193–C195.CrossRefGoogle ScholarPubMed
Cooper, GJS, Croxson, MS & Ibbertson, HK (1984) Iodine intake in an urban environment: a study of urine iodide excretion in Auckland. NZ Med J 97, 142–145.Google Scholar
Corvilain, B, Contempré, B, Longombé, A, Goyens, P, Gervy-Decoster, C, Lamy, F, Vanderpas, J & Dumont, J (1993) Selenium and the thyroid: how the relationship was established. Am J Clin Nutr 57, 244S–248S.CrossRefGoogle ScholarPubMed
Cressey, PJ & Vannoort, RW (1998) Iodine Content of New Zealand Dairy Products. Wellington: ESR.Google Scholar
Daniels, LA, Gibson, RA & Simmer, KM (2000) Indicators of selenium status in Australian infants. J Paediatr Child Health 36, 370–374.CrossRefGoogle ScholarPubMed
Darlow, BA, Inder, TE, Graham, PJ, Sluis, KB, Malpas, TJ, Taylor, BJ & Winterbourne, CC (1995) The relationship of selenium status to respiratory outcome in the very low birth weight infant. Pediatrics 96, 314–319.CrossRefGoogle ScholarPubMed
de Jong, N, Gibson, RS, Thomson, CD, Ferguson, EF, McKenzie, JE, Green, TJ & Horwath, CC (2001) Selenium and zinc status are suboptimal in a sample of older New Zealand women in a community-based study. J Nutr 131, 2677–2684.CrossRefGoogle Scholar
Department of Health (1991) Food For Health. Report of the New Zealand Nutrition Task Force. Wellington: Department of Health.Google Scholar
Department of Health and Human Services (2001) Iodine Monitoring Program DHHS-4137. Tasmania: Public and Environmental Health Service.Google Scholar
Derumeaux, H, Valeix, P, Castetbon, K, Bensimon, M, Boutron-Ruault, M-C, Arnaud, J & Hercberg, S (2003) Association of selenium with thyroid volume and echostructure in 35–60-year-old French adults. Eur J Endocrinol 148, 309–315.CrossRefGoogle Scholar
Duffield, AJ & Thomson, CD (1999) A comparison of methods of assessment of dietary selenium intakes in Otago, New Zealand. Br J Nutr 82, 131–138.CrossRefGoogle ScholarPubMed
Duffield, AJ, Thomson, CD, Hill, KE & Williams, S (1999) An estimation of selenium requirements for New Zealanders. Am J Clin Nutr 70, 896–903.CrossRefGoogle ScholarPubMed
Dunn, JT, Crutchfield, HE, Gutekunst, R & Dunn, AD (1993) Methods for Measuring Iodine in Urine. The Netherlands: ICCIDD/UNICEF/WHO.Google ScholarPubMed
Eastman, CJ (1993) The status of iodine nutrition in Australia. In Iodine Deficiency in Europe – A Continuing Concern, [Delange, F, Dunn, JT and Glinoer, D, editors]. New York: Plenum Press.Google Scholar
Eastman, CJ (1999) Where has all our iodine gone?. Med J Aust 171, 455–456.CrossRefGoogle ScholarPubMed
Fardy, JJMcOrist, GDFarrar, YJ (1989) The determination of selenium in the Australian diet using neutron activation analysis. J Radioanal Nucl Chem 133, 391–396.CrossRefGoogle Scholar
Fardy, JJ, McOrist, GD, Farrar, YJ, Bowles, CJ, Warnder, IM & Mingguang, T (1994) Application of neutron activation analysis and inductively coupled plasma mass spectrometry to the determination of toxic and essential elements in Australian Foods. In Nuclear Techniques for Toxic Elements in Foodstuffs, Report on an IAEA Co-ordination Research Programme, pp. 19–70Vienna: IAEA.Google Scholar
Food and Nutrition Board Institute of Medicine (2001) Dietary Reference Intakes for Vitamin A, Vitamin K, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press.Google Scholar
Frey, HMM, Rosenlund, B & Torgersen, JP (1978) Value of single urine specimens in estimation of 24 hour iodine excretion. Acta Endocrinol 72, 287–292.Google Scholar
Furnée, CA, van der Haar, F, West, CE & Hautvast, JGAJ (1994) A critical appraisal of goiter assessment and the ratio of urinary iodine to creatinine for evaluating iodine status. Am J Clin Nutr 59, 1415–1417.CrossRefGoogle ScholarPubMed
Gibson, HB (1995) Surveillance of iodine deficiency disorders in Tasmania 1949–1984 Department of Health Sciences Hobart.Google Scholar
Gibson, R (1990) Assessment of iodine status Principles of Nutritional Assessmen, pp. 527–532New York: Oxford University Press.Google Scholar
Goindi, G, Karmarkar, MG, Kapil, U & Jagannathan, J (1995) Estimation of losses of iodine during different cooking procedures. Asia Pac J Clin Nutr 4, 225–227.Google ScholarPubMed
Goyens, P, Golstein, J, Nsombola, B, Vis, H & Dumont, JE (1987) Selenium deficiency as a possible factor in the pathogenesis of myxoedematous endemic cretinism. Acta Endocrinol (Copenh) 114, 497–502.Google ScholarPubMed
Griffiths, NM & Thomson, CD (1974) Selenium in whole blood of New Zealand residents. NZ Med J 80, 199–202.Google ScholarPubMed
Gunton, JE, Hams, G, Fiegert, M & McElduff, A (1999) Iodine deficiency in ambulatory patients at a Sydney teaching hospital: is Australia truly iodine replete? Med J Aust 171, 467–470.CrossRefGoogle Scholar
Guttikonda, K, Burgess, JR, Hynes, K, Boyages, S, Byth, K & Parameswaran, V (2002) Recurrent iodine deficiency in Tasmania, Australia: A salutory lesson in sustainable iodine prophylaxis and its monitoring. J Clin Endocrinol Metab 87, 2809–2815.CrossRefGoogle Scholar
Hercus, CE, Benson, WN & Carter, CL (1925) Endemic goitre in New Zealand and its relation to the soil-iodine. J Hyg 24, 321–402.Google Scholar
Hetzel, BS & Dunn, JT (1989) The iodine deficiency disorders: their nature and prevention. Annu Rev Nutr 9, 21–38.CrossRefGoogle Scholar
Hynes, K (2001) Urinary Iodine Status of Tasmanian Primary School Children, pp. 44. Tasmania: Department of Health and Human Services, Tasmanian State Government.Google Scholar
Joerin, MM & Bowering, A (1972) The total iodine content of cow's milk. NZ Dairy Sci Tech 7, 155–158.Google Scholar
Judson, GJ (1987–1988) Report of the Central Veterinary Laboratories p. 7 Adelaide, SA, Australia: Department of Agriculture.Google Scholar
Kay, RG & Knight, GS (1979) Blood selenium in an adult Auckland population group. NZ Med J 90, 11–13.Google Scholar
Kidd, PS, Trowbridge, GL, Goldsby, JB & Nichman, MZ (1974) Sources of dietary iodine. J Am Diet Ass 65, 420–422.CrossRefGoogle ScholarPubMed
Knowles, SO, Lee, J & Grace, ND (1997) Metabolism of trace element in lactating cows: Perspectives of selenium and iodine in animal health and human nutrition. Proc Nutr Soc NZ 22, 174–183.Google Scholar
Kvícala, J, Zamrazil, V, Soutorová, M & Tomíska, F (1995) Correlations between parameters of body selenium status and peripheral thyroid parameters in the low selenium region. Analyst 120, 959–965.CrossRefGoogle ScholarPubMed
Li, M, Ma, G, Guttikonda, K, Boyages, SC & Eastman, CJ (2001) Re-emergence of iodine deficiency in Australia. Asia Pac J Clin Nutr 10, 200–203.CrossRefGoogle ScholarPubMed
Lyons, G, Stangoulis, J & Graham, R (2003) High-selenium wheat: biofortification for better health. Nutr Res Rev 16, 45–60.CrossRefGoogle ScholarPubMed
McElduff, A, McElduff, P, Gunton, JE, Hams, G, Wiley, V & Wicken, BM (2002) Neonatal thyroid-stimulatting hormone conentrations in northern Sydney: further indications of mild iodine deficiency. Med J Aust 176, 317–322.CrossRefGoogle Scholar
McLachlan, SK (2003) Selenium status of New Zealanders, MSc Thesis, University of Otago.Google Scholar
Marro, N (1996) The 1994 Australian Market Basket Survey. Canberra: Australia New Zealand Food Authority.Google Scholar
Melse-Boonstra, A, Rozendaal, M, Rexwinkel, H, Gerichhausen, JW, van den Briel, T, Bulux, J, Solomons, NW & West, CE (1998) Determination of discretionary salt intake in rural Guatemala and Benin to determine the iodine fortification of salt required to control iodine deficiency disorders: studies using lithium-labeled salt. Am J Clin Nutr 68, 636–641.CrossRefGoogle ScholarPubMed
Nève, J (1991) Methods in determination of selenium states. J Trace Elem Electrolytes Health Dis 5, 1–17.Google ScholarPubMed
Nève, J (1995) Human selenium supplementation as assessed by changes in blood selenium concentration and glutathione peroxidase activity. J Trace Elem Med Biol 9, 65–73.CrossRefGoogle ScholarPubMed
Nicolau, GY, Haus, E, Dumitriu, L, Plinga, L, Lakatua, DJ, Ehresman, D, Adderly, J, Sackett-Lundeen, L & Petrescu, E (1989) Circadian and seasonal variations in iodine excretion in children with and without endemic goiter. Roum Med Endocrinol 27, 73–86.Google ScholarPubMed
North, KAK & Fraser, S (1965) Iodine intake as revealed by urinary iodide excretion. NZ Med J 65, 512–513.Google Scholar
Olivieri, O, Girelli, D, Azzini, M, Stanzila, AM, Russo, C, Ferroni, M & Corrocher, R (1995) Low selenium status in the elderly influences thyroid hormones. Clin Sci 89, 637–642.CrossRefGoogle ScholarPubMed
Parnell, W, Scragg, R, Wilson, N, Schaaf, D & Fitzgerald, E (2003) NZ Food, NZ Children: Key Results of the 2002 National Children's Nutrition Survey. Wellington: Ministry of Health.Google Scholar
Patching, SG & Gardiner, PHE (1999) Recent developments in selenium metabolism and chemical speciation: A review. J Trace Elem Med Biol 13, 193–214.CrossRefGoogle ScholarPubMed
Paterson, E (2000) Selenium, oxidant stress and smoking, PhD Thesis, University of Otago.Google Scholar
Pharoah, PO, Connolly, KJ, Ekins, RD & Harding, AG (1984) Maternal thyroid hormone levels in pregnancy and the subsequent cognitive and motor performance of the children. Clin Endocrinol 21, 265–270.CrossRefGoogle ScholarPubMed
Purves, HD (1974) The aetiology and prophylaxis of endemic goitre and cretinism. The New Zealand experience. NZ Med J 80, 477–479.Google Scholar
Rasmussen, LB, Ovesen, L & Christiansen, E (1999) Day-to-day and within-day variation in urinary iodine excretion. Eur J Clin Nutr 53, 401–407.CrossRefGoogle ScholarPubMed
Rayman, MP (2000) The importance of selenium to human health. Lancet 356, 233–241.CrossRefGoogle ScholarPubMed
Rea, HM, Thomson, CD, Campbell, DR & Robinson, MF (1979) Relation between erythrocyte selenium concentrations and glutathione peroxidase ( EC 1.11.1.9) activities of New Zealand residents and visitors to New Zealand. Br J Nutr 42, 201–208.CrossRefGoogle ScholarPubMed
Reilly, C (1993) Selenium in health and disease: a review. Aust J Nutr Diet 50, 136–144.Google Scholar
Reilly, C, Barrett, JE, Patterson, CM & Tingii, U (1990) Trace element nutrition status and dietary intake of children with phenylketonuria. Am J Clin Nutr 52, 159–162.CrossRefGoogle ScholarPubMed
Reilly, C, Greaves, C, Patterson, C & Tingii, U (1991) Dietary selenium intake of Australian preschool children. In Trace Elements in Man and Animals – 7, [Momcilovic, B, editor]. Zagreb: Institute for Medical Research and Occupational Health, University of Zagreb.Google Scholar
Remer, T & Manz, F (1994) The inadequacy of the urinary iodine–creatinine ratio for the assessment of iodine status during infancy, childhood and adolescence. J Trace Elem Electr Health Dis 8, 217–219.Google ScholarPubMed
Robinson, MF (1989) Selenium in human nutrition in New Zealand. Nutr Rev 47, 99–107.CrossRefGoogle ScholarPubMed
Robinson, MF (1992) Recent investigations on trace elements, particularly selenium. In The Contribution of Nutrition to Human and Animal Health, pp. 174–183 [Widdowson, E and Mathews, J, editors]. Cambridge: Cambridge University Press.Google Scholar
Robinson, MF & Thomson, CD (1987) Status of the food supply and residents of New Zealand. In Selenium in Biology and Medicine, pp. 631–644 [Combs, GK, Spallholz, JE, Levander, OA and Oldfield, JE, editors]. New York: Van Nostrand Reinhold Company.Google Scholar
Russell, D, Parnell, W & Wilson, N (1999) NZ Food: NZ People. Key Results of the 1997 National Nutrition Survey, Wellington: Ministry of Health.Google Scholar
Sanchez-Castillo, CP, Warrender, S, Whitehead, TP & James, WPT (1987) An assessment of the sources of dietary salt in a British population. Clin Sci 72, 95–102.CrossRefGoogle Scholar
Scragg, R & Metcalf, P (2001) Pre-testing of Methodologies for the Children's Nutrition Survey, Report Four. Wellington: Ministry of Health.Google Scholar
Sheehan, TMT & Halls, DJ (1999) Measurement of selenium in clinical specimens. Ann Clin Biochem 36, 301–315.CrossRefGoogle ScholarPubMed
Simpson, FO, Thaler, BI, Paulin, JM, Phelan, EL & Cooper, GJS (1984) Iodide excretion in a salt-restriction trial. NZ Med J 97, 890–893.Google Scholar
Skeaff, SA, Ferguson, ELMcKenzie, JEValeix, P, Gibson, RS & Thomson, CD (2004) Are breast-fed infants and toddlers in New Zealand at risk of iodine deficiency? Nutrition (In the Press).CrossRefGoogle Scholar
Skeaff, S, Thomson, CD & Gibson, R (1999) Iodine Status in Schoolchildren. Wellington: Ministry of Health.Google Scholar
Skeaff, SA, Thomson, CD & Gibson, RS (2002) Mild iodine deficiency in a sample of New Zealand schoolchildren. Eur J Clin Nutr 56, 1169–1175.CrossRefGoogle Scholar
Standing Committee on the Evaluation of Dietary Reference Intakes of the Food and Nutrition Board Institute of Medicine, the National Academies and Health Canada (2000) Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium and Carotenoids Washington, DC: National Academy Press.Google Scholar
Stewart, JC, Vidor, GI, Buttfield, IH & Hetzel, BS (1971) Epidemic thyrotoxicosis in northern Tasmania. Aust NZ J Med 1, 203–211.CrossRefGoogle ScholarPubMed
Sumar, S & Ismail, H (1997) Iodine in food and health. Nutr Food Sci 5, September/October 177–183.Google Scholar
Sutcliffe, E (1990) Iodine in New Zealand milk. Food Tech NZ 7, 32–38.Google Scholar
Tasmanian Thyroid Advisory Committee (1981) Study in disease surveillance. Med J Aust 2, 234–238.Google Scholar
Thomson, CD (2002) Dietary recommendations for iodine around the world. In IDD Newsletter pp. 45–60.Google Scholar
Thomson, CD, Colls, AJ, Conaglen, JV, Macormake, M, Stiles, M & Mann, J (1997a) Iodine status of New Zealand residents as assessed by urinary iodide excretion and thyroid hormones. Br J Nutr 78, 901–912.CrossRefGoogle ScholarPubMed
Thomson, CD, Colls, AJ, Styles, M & Conaglen, J (1997b) Urinary iodide excretion in New Zealand residents. In Trace Elements in Man and Animals – 9, pp. 118–119 [Fischer, PWF, L'Abbé, MR, Cockell, KA and Gibson, RS, editors]. Ottawa: NRC Research Press.Google Scholar
Thomson, CD, Ong, LK & Robinson, MF (1985) Effects of supplementation with high-selenium wheat bread on selenium glutathione peroxidase and related enzymes in blood components of New Zealand residents. Am J Clin Nutr 41, 1015–1022.CrossRefGoogle ScholarPubMed
Thomson, CD, Packer, MA, Butler, JA, Duffield, AJ, O'Donaglue, KL & Whanger, PD (2001a) Urinary selenium and iodine during pregnancy and lactation. J Trace Elem Med Biol 14, 210–217.CrossRefGoogle ScholarPubMed
Thomson, CD & Paterson, E (2001) Australian and New Zealand Nutrient Reference Values for Selenium. Wellington: Ministry of Health.Google Scholar
Thomson, CD & Robinson, MF (1988) Food concentrations and dietary intakes of selenium in Otago, New Zealand. In Trace Elements in New Zealand: Environmental, Human and Animal, pp. 113–117 [McLaren, RG, Haynes, RJ and Savage, GP, editors]. Canterbury, NZ: Lincoln College.Google Scholar
Thomson, CD & Robinson, MF (1990) Selenium content of foods in Otago, New Zealand. NZ Med J 103, 130–135.Google ScholarPubMed
Thomson, CD & Robinson, MF (1996) The changing selenium status of New Zealand residents. Eur J Clin Nutr 50, 107–114.Google ScholarPubMed
Thomson, CD, Robinson, MF, Butler, JA & Whanger, PD (1993) Long-term supplementation with selenate and selenomethionine: selenium and glutathione peroxidase ( EC 1.11.1.19) in blood components of New Zealand women. Br J Nutr 69, 577–588.CrossRefGoogle Scholar
Thomson, CD, Robinson, MF, Campbell, DR & Rea, HM (1982) Effect of prolonged supplementation with daily supplements of selenomethionine and sodium selenite on glutathione peroxidase activity in blood of New Zealand residents. Am J Clin Nutr 36, 24–31.CrossRefGoogle ScholarPubMed
Thomson, CD, Smith, TE, Butler, KA & Packer, MA (1996) An evaluation of urinary measures of iodine and selenium status. J Trace Elem Med Biol 10, 214–222.CrossRefGoogle ScholarPubMed
Thomson, CD, Steven, SM, Van Rij, AM, Wade, CR & Robinson, MF (1988) The effect of supplementation with selenium and α-tocopherol on activities of glutathione peroxidase and related enzymes in human tissues. Am J Clin Nutr 48, 316–323.CrossRefGoogle Scholar
Thomson, CD, Woodruffe, S, Colls, AJ, Joseph, J & Doyle, TC (2001b) Urinary iodine and thyroid status of New Zealand residents. Eur J Clin Nutr 55, 387–392.CrossRefGoogle ScholarPubMed
Tinggi, U (1999) Determination of selenium in meat products by hydride generation atomic absorption spectrophotometry. JAOC Int 82, 364–367.Google ScholarPubMed
Tinggi, U (2003) Essentiality and toxicity of selenium and its status in Australia: a review. Toxicol Rev 137, 103–110.Google ScholarPubMed
Tinggi, U, Reilly, C & Patterson, CM (1992) Determination of selenium in foodstuffs using spectroflurometry and hydride generation atomic absorption spectrometry. J Food Comp Anal 5, 269–282.CrossRefGoogle Scholar
Twomey, A (1968) Iodophors: their physical, chemical and bactericidal properties and use in the dairy industry a review. Aust J Dairy Tech 23, 162–165.Google Scholar
Van Rij, AM, Thomson, CD, McKenzie, JM & Robinson, MF (1979) Selenium deficiency in total parenteral nutrition. Am J Clin Nutr 32, 2076–2085.CrossRefGoogle ScholarPubMed
Vanderpas, JB, Contempré, B, Duale, NL, Deckx, NL, Bebe, N, Longombé, AO, Thilly, C-H, Diplock, A & Dumont, JE (1993) Selenium deficiency mitigates hypothyroxinemia in iodine-deficient subjects. Am J Clin Nutr 57, 271S–275S.CrossRefGoogle ScholarPubMed
Vannoort, R, Cressey, P & Silvers, K (2000) 1997/1998 New Zealand Total Diet Survey. Part 2: Elements. Wellington: Ministry of Health.Google Scholar
Wang, GY, Zhou, RH, Wang, Z, Shi, L & Sun, M (1999) Effects of storage and cooking on the iodine content in iodized salt and study on monitoring iodine content in iodized salt. Biomed Environ Sci 12, 1–9.Google Scholar
Wenlock, RW, Buss, DH, Moxon, RE & Bunton, NG (1982) Trace elements 4: Iodine in British foods. Br J Nutr 7, 381–390.CrossRefGoogle Scholar
World Health Organization/United Nations International Children's Emergency Fund/Centre for the Control of Iodine Deficiency Disorders (1994) Indicators for Assessing Iodine Deficiency Disorders and their Control Through Salt Iodization. Geneva: WHO.Google Scholar
Winterbourne, CC, Saville, DJ, George, PM & Walmsley, TA (1992) Increase in selenium status of Christchurch adults associated with deregulation of the wheat market. NZ Med J 105, 466–468.Google Scholar
Yang, G-Q, Wang, S-Z, Zhou, R-H & Sun, S-Z (1983) Endemic selenium intoxication of humans in China. Am J Clin Nutr 37, 872–881.CrossRefGoogle ScholarPubMed
Zimmerman, MB, Molinari, L, Spehl, M, Weidinger-Toth, J, Podoba, J, Hess, S & Delange, F (2001) Toward a consensus on reference values for thyroid volume in iodine-replete school-children: Results of a workshop in sonographic measurement of thyroid volume. Eur J Endocrinol 144, 213–220.CrossRefGoogle Scholar