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PEDIATRICS Vol. 112 No. 6 December 2003, pp. 1419-1420

COMMENTARY

Zinc, Low Birth Weight, and Breastfeeding

K. Michael Hambidge, MD, ScD and Nancy F. Krebs, MD, MS, FAAP

Section of Nutrition
Department of Pediatrics
University of Colorado Health Sciences Center
Denver, CO 80262

Abbreviations: SGA, small for gestational age

The article by Sur et al¹ in this issue further emphasizes the value of both breastfeeding and an adequate zinc intake for infants. The notable contribution of zinc deficiency in infancy and early childhood to stunting² and infectious disease morbidity³ and mortality,⁴ especially from diarrhea and pneumonia, is now well-documented in developing countries.

In the study by Sur et al, zinc supplementation of low birth weight infants for the first year of life was associated with improved growth and reduced diarrheal morbidity. In another study from India, zinc supplementation of small for gestational age (SGA) infants from 1 to 10 months postnatal age was associated with a two-thirds reduction in mortality.⁵ Most low birth weight infants in developing countries are SGA. Neonatal reserves of zinc in SGA infants are lower than those of appropriate for gestational age infants, even on a body weight basis,⁶ and these supplementation studies support a particular vulnerability to zinc deficiency in this group. Thus special attention to an adequate postnatal zinc intake is indicated for the SGA infant.

The independent protective effect of exclusive breastfeeding noted in this study raises the question of whether the diarrhea associated with introduction of potentially contaminated complementary foods at 4 months caused increased zinc losses and whether, had exclusive breastfeeding been continued longer, the onset of zinc deficiency would have been delayed. Alternatively, zinc deficiency may have been developing by 4 months, resulting in increased susceptibility to diarrhea. This study does not answer these questions but illustrates well the challenge of defining optimal timing of introduction of complementary foods, especially in vulnerable infants in vulnerable conditions. There is little doubt that even the term, appropriate for gestational age, older breastfed infant is susceptible to zinc deficiency after 6 months when milk zinc concentrations are very low relative to requirements.^7,8 The availability of complementary foods of favorable bioavailability, especially animal products, is critical to attaining adequate zinc intake. In our experience, poor appetite and slow growth attributable to zinc deficiency occur in North America in older breastfed infants if complementary foods with bioavailable zinc, such as meats, are not consumed. The studies by Sur et al and others are reminders of both the importance and complexity of meeting the needs of this micronutrient in the breastfed infant by midinfancy and of the special vulnerability to zinc deficiency associated with even modestly low birth weight.

	FOOTNOTES

 
Received for publication Aug 1, 2003; Accepted Aug 1, 2003.

Address correspondence to Nancy F. Krebs, MD, MS, Department of Pediatrics, University of Colorado Health Sciences Center, 4200 E 9th Ave, Box C225, Denver, CO 80262. E-mail: nancy.krebs{at}uchsc.edu

	REFERENCES

TOP REFERENCES

 

1. Sur D, Gupta DN, Mondal SK, et al. Impact of zinc supplementation on diarrheal morbidity and growth pattern of low birth weight infants in Kolkata, India: a randomized, double-blind, placebo-controlled, community-based study. Pediatrics.2003; 112 :1327 –1332[Abstract/Free Full Text]
2. Brown KH, Peerson JM, Rivera J, Allen LH. Effect of supplemental zinc on the growth and serum zinc concentrations of prepubertal children: a meta-analysis of randomized controlled trials. Am J Clin Nutr.2002; 75 :1062 –1071[Abstract/Free Full Text]
3. Bhutta ZA, Black RE, Brown KH, et al. Prevention of diarrhea and pneumonia by zinc supplementation in children in developing countries: pooled analysis of randomized controlled trials. Zinc Investigators’ Collaborative Group. J Pediatr.1999; 135 :689 –697[CrossRef][Web of Science][Medline]
4. Jones G, Steketee RW, Black RE, Bhutta ZA, Morris SS, Bellagio Child Survival Study. How many child deaths can we prevent this year? Lancet.2003; 362 :65 –71[CrossRef][Web of Science][Medline]
5. Sazawal S, Black RE, Menon VP, et al. Zinc supplementation in infants born small for gestational age reduces mortality: a prospective, randomized, controlled trial. Pediatrics.2001; 108 :1280 –1286[Abstract/Free Full Text]
6. Krebs NF, Bartlett A, Westcott JE, et al. Exchangeable zinc pool size is smaller at birth in small for gestational age infants [abstract]. Pediatr Res.2003; 53 :394A
7. Krebs NF, Reidinger CJ, Miller LV, Hambidge KM. Zinc homeostasis in breast-fed infants. Pediatr Res.1996; 39 :661 –665[Web of Science][Medline]
8. Umeta M, West CE, Haidar J, Deurenberg P, Hautvast JG. Zinc supplementation and stunted infants in Ethiopia: a randomised controlled trial. Lancet.2001; 355 :2021 –2026

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PEDIATRICS (ISSN 1098-4275). ©2003 by the American Academy of Pediatrics

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This Article Extract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services E-mail this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Hambidge, K. M. Articles by Krebs, N. F. Search for Related Content PubMed PubMed Citation Articles by Hambidge, K. M. Articles by Krebs, N. F. Related Collections Premature & Newborn Social Bookmarking                         What's this?