Comparison of complementary feeding strategies to meet zinc requirements of older breastfed infants

Am J Clin Nutr. 2012 Jul;96(1):30-5. doi: 10.3945/ajcn.112.036046. Epub 2012 May 30.


Background: The low zinc intake from human milk at ∼6 mo of age predicts the dependence on complementary foods (CF) to meet the zinc requirements of older breastfed-only infants.

Objective: The objective of this study was to compare major variables of zinc homeostasis and zinc status in 9-mo-old breastfed infants who were randomly assigned to different complementary food regimens.

Design: Forty-five exclusively breastfed 5-mo-old infants were randomly assigned to receive commercially available pureed meats, iron-and-zinc-fortified infant cereal (IZFC), or whole-grain, iron-only-fortified infant cereal (IFC) as the first and primary CF until completion of zinc metabolic studies between 9 and 10 mo of age. A zinc stable-isotope methodology was used to measure the fractional absorption of zinc (FAZ) in human milk and CF by dual-isotope ratios in urine. Calculated variables included the dietary intake from duplicate diets and 4-d test weighing, the total absorbed zinc (TAZ) from FAZ × diet zinc, and the exchangeable zinc pool size (EZP) from isotope enrichment in urine.

Results: Mean daily zinc intakes were significantly greater for the meat and IZFC groups than for the IFC group (P < 0.001); only intakes in meat and IZFC groups met estimated average requirements. Mean (±SEM) TAZ amounts were 0.80 ± 0.08, 0.71 ± 0.09, and 0.52 ± 0.05 mg/d for the meat, IZFC, and IFC groups, respectively (P = 0.027). Zinc from human milk contributed <25% of TAZ for all groups. The EZP correlated with both zinc intake (r = 0.43, P < 0.01) and TAZ (r = 0.54, P < 0.001).

Conclusion: Zinc requirements for older breastfed-only infants are unlikely to be met without the regular consumption of either meats or zinc-fortified foods.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers / blood
  • Biomarkers / urine
  • Breast Feeding*
  • Colorado
  • Edible Grain / chemistry
  • Female
  • Food, Fortified / analysis
  • Homeostasis
  • Humans
  • Infant
  • Infant Food / analysis*
  • Infant Nutritional Physiological Phenomena*
  • Intestinal Absorption
  • Male
  • Meat Products / analysis
  • Milk, Human / chemistry
  • Nutritional Requirements
  • Nutritional Status
  • Phytic Acid / administration & dosage
  • Phytic Acid / analysis
  • Zinc / administration & dosage*
  • Zinc / analysis
  • Zinc / deficiency
  • Zinc / metabolism


  • Biomarkers
  • Phytic Acid
  • Zinc