Pilot Study: Tendency of Increasing Iodine Content in Human Milk and Cow's Milk

Abstract

The iodine supply in Germany has improved throughout the last decade, albeit with enormous differences between individuals and regions. In the Thuringian city of Jena, analyses of the iodine content of human milk have been undertaken regularly since 1982. Significantly increasing iodine concentrations in human and cow's milk have been found. Therefore, the current situation and the effectiveness of measures to prevent iodine deficiency demands re-evaluation. The iodine content of human milk from 32 lactating mothers was analysed on the 5th day (mean) postpartum and mothers' dietary iodine intake during the last two months of pregnancy was assessed by means of a food frequency questionnaire. To corroborate the assumption that the increasing iodine levels of cow's milk are one of the main reasons for the improved iodine supply, the iodine concentration of 34 cow's milk bulk-samples was also determined. Both human and cow's milk samples were analysed by the ICP-MS method. Twenty women took iodine supplements (mean daily intake = 175 µg). The average daily iodine intake of the 20 supplemented and 12 non-supplemented women was 258 µg and 116 µg, respectively. Daily iodine intake from food and beverages was significantly lower in supplemented women (83 µg/day). The average iodine content of human milk was 169 ± 88 µg/l with a range of 33 - 348 µg/l. This content is two times higher than levels from 1994 in the same area. There was no difference in the human milk iodine content between mothers taking supplements and those who did not. Cow's milk samples showed a mean iodine concentration of 178 ± 131 µg/l (range 48 - 661 µg/l).

Prophylaxis of iodine deficiency - iodine supplementation - human milk - cow's milk

References

• 1 Adam O. The need for nutritional supplements - Iodine.  Ernähr Umschau. 2003;  50 352-356
• 2 Als C, Haldimann M, Bürgi E, Donati F, Gerber H, Zimmerli B. Swiss pilot study of individual seasonal fluctuations of urinary iodine concentration over two years: is age-dependency linked to the major source of dietary iodine?.  Eur J Clin Nutr. 2003;  57 636-646
• 3 Anke M, Glei M, Groppel B, Rother C, Gonzales D. Mengen-, Spuren- und Ultraspurenelemente in der Nahrungskette.  Nova Acta Leopoldina NF 79. 1998;  309 157-190
• 4 Anonymous. DIN 32 645 Nachweis-, Erfassungs- und Bestimmungsgrenze. Deutsche Einheitsverfahren zur Wasser-, Abwasser- und Schlammuntersuchung - Chemische Analytik. Berlin; Beuth 1994
• 5 Anonymous. “Vital & Active”. Bayer Vital GmbH & Co KG Software 1999
• 6 DACH .Referenzwerte für die Nährstoffzufuhr. Herausgeber: DGE, ÖGE, SGE, SVE. Frankfurt am Main; Umschau Braus Verlag 2000
• 7 Delange F. Physiopathology of iodine nutrition. Chandra RK Trace Elements in Nutrition of Children. Nestlé Nutrition. New York; Vevey/Raven Press 1989: 291-299
• 8 DGE .Ernährungsbericht 2000. Frankfurt am Main; DGE 2000
• 9 Dorea J G. Iodine nutrition and breast feeding.  J Trace Elem Med Biol. 2002;  16 207-220
• 10 Falkenberg U, Tenhagen B A, Forderung D, Heuwieser W. Effect of predipping with a iodophor teat disinfectant on iodine content of milk.  Milchwissenschaft - Milk Sci Int. 2002;  57 599-601
• 11 Hampel R, Gordalla A, Zollner H, Klinke D, Demuth M. Continuous rise of urinary iodine excretion and drop in thyroid gland size among adolescents in Mecklenburg-West-Pomerania from 1993 to 1997.  Exp Clin Endocrinol Diabetes. 2000;  108 197-201
• 12 Hampel R, Beyersdorf-Radeck B, Below H, Demuth M, Seelig K. Urinary iodine levels within normal range in German school-age children.  Med Klin. 2001;  96 125-128
• 13 Hesse V. Personal information. 2002
• 14 Jahreis G, Leiterer M, Franke K, Maichrowitz W, Schöne F, Hesse V. Jodversorgung bei Schulkindern und zum Jodgehalt der Milch.  Kinderärztl Praxis. 1999;  16 172-181
• 15 Jahreis G, Hausmann W, Kiessling G, Franke K, Leiterer M. Bioavailability of iodine from normal diets rich in dairy products - results of balance studies in women.  Exp Clin Endocrinol Diabetes. 2001;  109 163-167
• 16 Langford N J, Lewis D J, Crews H M. Iodine speciation in pasteurized milk and infant formulae. 10th Biennial National Atomic Special Symposium, 17 - 20 July 2000. Sheffield Hallum University; 2000: Abstract C23
• 17 Laurberg P, Andersen S, Knudsen N, Ovesen L, Nohr S B, Bulow Pedersen I. Thiocyanate in food and iodine in milk: from domestic animal feeding to improved understanding of cretinism.  Thyroid. 2002;  10 897-902
• 18 Leiterer M, Truckenbrodt D, Franke K. Determination of iodine species in milk using ion chromatographic separation and ICP-MS detection.  Eur Food Res Technol. 2001;  213 150-153
• 19 Moon S, Kim J. Iodine content of human milk and dietary intake of Korean lactating mothers.  Int J Food Sci Nutr. 1999;  50 165-171
• 20 Preiß U, Santos C A, Spitzer A, Wallnöfer P R. Der Jodgehalt der bayerischen Konsummilch.  Z Ernährungswiss. 1997;  36 220-224
• 21 Roth C, Meller J, Bobrzik S, Thal H, Becker W, Kulenkampff D, Lakomek M, Zappel H. The iodine supply of newborns. Comparison of iodine absorption and iodine excretion of mother and child.  Dtsch Med Wochenschr. 2001;  126 321-325
• 22 Seibold-Weiger K, Wollmann H, Rendl J, Ranke M, Speer C. Iodine concentration in the breast milk of mothers of premature infants.  Z Geburtshilfe. 1999;  203 81-85
• 23 Semba R D, Delange F. Iodine in human milk: Perspectives for infant health.  Nutr Rev. 2001;  59 269-278
• 24 Willgerodt H, Keller E, Perschke C, Stach B. The status of iodine nutrition in newborn infants, schoolchildren, adolescents and adults in former East Germany.  Exp Clin Endocrinol Diabetes. 1997;  105 (Suppl 4) 38-42
• 25 Zöllner H, Franke G, Piek M, Below H, Rose H J, Kramer A. Urinary iodide excretion, thyroid volumes and TSH serum concentrations in adults in West Pomerania.  Ernährungs-Umschau. 2002;  11 424-427