Meeting the iron needs of infants and young children: an update

Nutrition Committee, Canadian Paediatric Society (CPS)

Approved by the CPS Board of Directors in 1991

Canadian Medical Association Journal 1991; 144(11): 1451-1454

Reference No. N91-01

An index of position papers from this committee is available here.

Paper reprints of this position paper may be obtained from: Canadian Paediatric Society, 100-2204 Walkley Road, Ottawa ON &nbspK1G 4G8; Phone : (613) 526-9397; Fax : (613) 526-3332 

Contents


Iron deficiency remains a nutritional problem among infants and young children in Canada. Although there are no recent national data, the prevalence of iron deficiency and iron deficiency anemia among infants at low risk was 3.5% for those 6 months of age and 10.5% for those 18 months of age.1 Among infants aged 10 to 14 months of low-income families in Montreal, 24.3% were found to have iron deficiency anemia.2 At high risk for iron deficiency are preterm infants and infants from a low socioeconomic background. The Canadian Task Force on the Periodic Health Examination recommends that high-risk infants be screened for iron deficiency at 9 months of age.3 Other risk factors include low birth weight,4 perinatal bleeding, a low hemoglobin concentration at birth, chronic hypoxia, frequent infections, early intake of cow's milk or solid food, or both, frequent and excessive tea intake, low vitamin C or meat intake, breast-feeding for more than 6 months without supplemental iron, intake of infant formula not fortified with iron for more than 4 months without other foods,5 and ethnic practices.6

Nonhematologic consequences of iron deficiency include poor weight gain, anorexia, blood in stools, malabsorption, irritability, decreased attention span, exercise intolerance and decreased physical activity.7 A recent study on iron deficiency anemia and psychomotor development8 concluded that when iron deficiency progresses to anemia, performance on developmental tests is adversely affected for up to at least 3 months despite correction of the anemia with iron therapy. Among infants with severe or chronic iron deficiency, some of these abnormalities may persist indefinitely despite adequate iron therapy.9 The relation between iron deficiency and behavioural development has been the subject of a recent international conference.10

Infant feeding patterns have undergone some notable changes since the mid-1970s. More mothers breast-feed and do so for at least 6 months, and fewer introduce solid foods before 4 months or unmodified cow's milk before 6 months.11,12 However, these changes have not occurred in all parts of Canada,1 and whether they will continue is unknown.

Iron requirements

Newborn term infants have approximately 75 mg/kg of body iron, 75% of which is in the form of hemoglobin. On average, infants almost triple their blood volume during the first year of life and will require the absorption of 0.4 to 0.6 mg daily of iron during that time to maintain adequate stores.13

Premature infants have a lower level of body iron at birth, approximately 64 mg in infants weighing 1 kg. The loss of blood drawn for laboratory tests and the rapid rate of postnatal growth lead to a higher requirement for dietary iron than in term infants — 2.0 to 2.5 mg/kg daily to prevent late anemia.14

Assuming that 10% of the iron in a mixed diet is absorbed, the recommended iron intake is approximately 7 mg/d for term infants aged 5 to 12 months, 6 mg/d for toddlers aged 1 to 3 years and 8 mg/d for children aged 4 to 12 years.15

Dietary sources of Iron

Other factors affecting iron sufficiency are the amount and the bioavailability of dietary iron. The form of the iron influences its absorption: absorption is good from ferrous sulfate (the iron source generally used in infant formulas) and elemental iron of small particle size (e.g., the electrolytic iron used in infant cereals). In general, iron absorption from foods of animal origin surpasses that from foods of plant origin. Vitamin C, meat, fish and poultry facilitate iron absorption.16

One litre of human milk contains only 0.3 to 0.5 mg of iron. About 50% of the iron is absorbed, in contrast to a much smaller proportion from other foods. Term infants who are breast-fed exclusively for the first 6 months may not be at risk for iron depletion or for the development of iron deficiency.13 However, if solid foods are given they may compromise the bioavailability of iron from human milk.17,18 Although some term infants who are exclusively breast-fed may remain iron-sufficient until 9 months of age,19 a source of dietary iron is recommended starting at 6 months (or earlier if solid foods are introduced into the diet) to reduce the risk of iron deficiency.

Infant formulas based on cow's milk contain 1.0 to 1.5 mg of iron per litre; soy-based formula and iron-fortified formula based on cow's milk contain 12 to 13 mg of iron per litre. The iron source of fortified formulas is ferrous sulfate, which is significantly more available than the iron used in infant cereals.20,21 The availability of iron from soy-based formulas appears to be lower than that from milk-based products.22 The optimal amount of iron in formula based on cow's milk remains to be determined. Formulas in North America contain higher amounts of iron than those suggested in the United Kingdom (1.0 mg/100 kcal) and France (1.5 mg/100 kcal).

The decreased incidence of iron deficiency anemia in the United States since 1969 has been attributed to the increased and longer use of iron-fortified formulas, an increase in breast-feeding and the use of iron-fortified infant cereals.23,24 Contrary to popular belief, significant behavioural or gastrointestinal problems do not develop in most infants fed iron-fortified formulas.25,26 Theoretically, the iron from neonatal reserves in term babies is sufficient to cover their needs during the first 3 months of life. However, in order to avoid possible confusion with formula changes during the first few months, iron-fortified formulas should be used from birth.

Cow's milk is not recommended for infants younger than 9 to 12 months of age. Although it contains approximately the same amount of iron as human milk (0.5 mg/L) the iron is poorly absorbed. Even when given iron-fortified cereals and other foods, some infants fed cow's milk from 6 months of age have significantly lower mean serum ferritin levels and corpuscular volume and a greater incidence of hemoglobin concentration below 6.8 mmol/L at 12 months of age than infants fed iron-supplemented formula.27 In addition, cow's milk compromises the absorption of dietary and medicinal iron.

Occult blood loss from the gastrointestinal tract has been demonstrated in infants younger than 4 months of age fed exclusively with unmodified cow's milk.28 A more recent study of the effects of cow's milk on infants from 168 to 252 days old showed significant gastrointestinal blood loss in the experimental group, as measured by a sensitive quantitative method;29 however, this group's iron nutritional status was not significantly different from that of the control (formula-fed) group.

Iron-fortified cereals are an important source of iron: they contain approximately 30 to 50 mg per 100 g of cereal, of which 40n average will normally be absorbed.30 Although the bioavailability of iron in infant cereals has been challenged,31 several studies have demonstrated that it is 50% to 70% of the bioavailability of ferrous sulfate, a generally accepted standard.20,32-34 Furthermore, clinical studies have shown that iron-fortified infant cereals and formulas can maintain adequate iron status in healthy term infants.35-37

Recommendations

Term infants who are exclusively breast-fed do not need supplemental iron until they are 6 months of age. If solid foods are introduced earlier, they should contain an adequate amount of iron. After 6 months of age, breast-fed infants should receive extra iron in the form of iron-fortified infant cereals and other iron-rich foods. These infants should be offered an iron-fortified infant formula after they have been weaned from breast milk.

Term infants who are not breast-fed should be given an iron-fortified infant formula from birth. Studies are still under way to determine the optimal iron content of these formulas: and further studies are encouraged. Until the results are known, the use of currently available iron-fortified formulas seems appropriate. After 4 to 6 months of age, iron-fortified infant cereals provide a good additional source of iron.

For premature infants, an iron supplement should be started by at least 8 weeks of age and continued until the first birthday. Iron-fortified formula for bottle-fed infants or commercial iron drops for breast-fed infants are the recommended source of supplemental iron.

Cow's milk should not be introduced until an adequate amount of solid food containing iron and vitamin C is included in the diet, preferably at 9 to 12 months of age.

For children over 1 year of age, the recommended daily nutrient intake of iron should be given. Iron-containing foods such as meats, some vegetables, legumes, fruits and iron-fortified infant or toddler cereals provide iron in sufficient amounts. Supplemental iron is not required unless the diet is lacking in these foods.

References

  1. Greene-Finestone L, Feldman W, Heick H et al: Infant feeding practices and socio-demographic factors in Ottawa-Carleton. Can J Public Health 1989; 80: 173-176
  2. Gray-Donald K, Di-Tommaso S, Leamann F et al: The prevalence of iron deficiency anemia in low income Montreal infants aged 10-14 months [abstr]. J Can Diet Assoc 1990; 51: 424
  3. Canadian Task Force on the Periodic Health Examination: The periodic health examination. Can Med Assoc J 1979; 121: 1193-1254
  4. Friel JK, Andrews WL, Matthew JD et al: Iron status of very-low-birth-weight infants during the first 15 months of infancy. Can Med Assoc J 1990; 143: 733-737
  5. Reeves JD: Iron supplementation in infancy. Pediatr Rev 1986; 8: 177-184
  6. Chan-Yip A, Gray-Donald K: Prevalence of iron deficiency among Chinese children aged 6 to 36 months in Montreal. Can Med Assoc J 1987; 136: 373-376, 378
  7. Jacobs A: Non-haematological effects of iron deficiency. Clin Haematol 1982; 11: 353-364
  8. Walter T, De Andraca I, Chadud P at al: Iron deficiency anemia: adverse effects on infant psychomotor development. Pediatrics 1989; 84: 7-17
  9. Lozoff B, Brittenham GM, Wolf AW et al: Iron deficiency anemia and iron therapy: effects on infant developmental test performance. Pediatrics 1987; 79: 981-995
  10. Haas JD, Fairchild MW: Summary and conclusion of the International Conference on Iron Deficiency and Behavioral Development, October 10-12, 1988. Am J Clin Nutr 1989; 50: 703-705
  11. Myres AW: Canadian progress in the promotion of breast-feeding, 1965-1985. In Proceedings of the 12th World Conference on Health Education, Health Education Bureau, Dublin, 1987: 903-914
  12. Tanaka PA, Yeung DL, Anderson GH: Infant feeding practices: 1984-85 versus 1977-78. Can Med Assoc J 1987; 136: 940-944
  13. Duncan B, Schifman RB, Corrigan JJ Jr et al: Iron and the exclusively breast-fed infant from birth to six months. J Pediatr Gastroenterol Nutr 1985; 4: 421-425
  14. Wharton BA (ed): Nutrition and Feeding of Preterm Infants, Blackwell Pubns, Palo Alto, Calif, 1987: 113-142
  15. Nutrition Recommendations: the Report of the Scientific Review Committee, Dept of National Health and Welfare, Ottawa, 1990
  16. Fairweather-Tait SJ: Iron in food and its availability. Acta Paediatr Scand Suppl 1989; 361: 12-20
  17. Saarinen UM, Siimes MA: Iron absorption from breast milk, cow's milk, and iron supplemented formula: an opportunistic use of changes in total body iron determined by hemoglobin, ferritin, and body weight in 132 infants. Pediatr Res 1979; 13: 143-147
  18. Oski FA, Landaw SA: Inhibition of iron absorption from human milk by baby food. Am J Dis Child 1980; 134: 459-460
  19. Siimes MA, Salmenpera L, Perheentupa J: Exclusive breast feeding for nine months: a risk of iron deficiency. J Pediatr 1984; 104: 196-199
  20. Forbes AL, Adams CE, Arnaud MJ et al: Comparison of in vitro, animal, and clinical determinations of iron bioavailability: International Nutritional Anemia Consultative Group Task Force report on iron bioavailability. Am J Clin Nutr 1989; 49: 225-238
  21. Fairweather-Tait SJ: The concept of bioavailibility as it relates to iron nutrition. Nutr Res (New York) 1987; 7: 319-325
  22. Brennan MM, Flynn A, Morrissey PA: Absorption of iron and zinc from soya and cow's milk-based infant formulae in sucking rats [abstr]. Proc Nutr Soc 1989; 48: 39A
  23. Yip R, Binkin NJ, Fleshood L et al: Declining prevalence of anemia among low-income children in the United States. JAMA 1987; 258: 1619-1623
  24. Yip R, Walsh KM, Goldfarb MG et al: Declining prevalence of anemia in childhood in a middle-class setting: A pediatric success story? Pediatrics 1987; 80: 330-334
  25. Oski FA: Iron fortified formulas and gastrointestinal symptoms in infants: a controlled study. Pediatrics 1980; 66: 168-170
  26. Nelson SE, Ziegler EE, Copeland AM et al: Lack of adverse reactions to iron-fortified formula. Pediatrics 1988; 81: 360-364
  27. Tunnessen WW Jr, Oski FA: Consequences of starting whole cow milk at 6 months of age. J Pediatr 1987; 111: 813-816
  28. Fomon SJ, Ziegler EE, Nelson SE et al: Cow milk feeding in infancy: gastrointestinal blood loss and iron nutritional status. J Pediatr 1981; 98: 540-545
  29. Ziegler EE, Fomon SJ, Nelson SE et al: Cow milk feeding in infancy: further observations on blood loss from the gastrointestinal tract. J Pediatr 1990; 116: 11-18
  30. Rios E, Hunter RE, Cook JD et al: The absorption of iron as supplements in infant cereals and infant formulas. Pediatrics 1975; 55: 686-693
  31. Fomon SJ: Bioavailability of supplemental iron in commercially prepared dry infant cereals. J Pediatr 1987; 110: 660-661
  32. Anderson TA, Filer LJ, Fomon SJ et al: Bioavailability of different sources of dietary iron fed to Pitman-Moore miniature pigs. J Nutr 1974; 104: 619-628
  33. Shah BG, Belonje B: The lack of effect of added dibasic calcium phosphate on the bioavailability of electrolytic iron in infant cereals. Nutr Res (New York) 1985; 5: 181-188
  34. Romanik EM, Miller DD: Iron bioavailability to rats from fortified infant cereals: a comparison of oatmeal and rice cereals. Nutr Rep Int 1986; 34: 591-603
  35. Hertrampf E, Cayazzo M, Pizarro MT et al: Bioavailability of iron in soy-based formulas and its effect on iron nutriture in infancy. Pediatrics 1986; 78: 640-645
  36. Brown MK, Picciano MF: Relative effectiveness of food sources of supplemental iron to the infant. Fed Proc 1987; 46: 1160
  37. Feldman W, Green-Finestone L, Heick H et al: Do all infants need to be screened for anemia? or iron deficiency [abstr]? Clin Invest Med 1985; 8 (3): A182
 

Nutrition Committee Members: Drs. Micheline Ste-Marie (chairman and principal author), Department of Paediatrics, Izaak Walton Killam Hospital for Children, Halifax, NS; Mimi M. Belmonte (director responsible), Department of Endocrinology and Metabolism, Montreal Children's Hospital, Montreal, Que.; Margaret P. Boland, Department of Paediatrics, Children's Hospital of Eastern Ontario, Ottawa, Ont.; Robert M. Issenman, Department of Pediatrics, McMaster University, Hamilton, Ont.; John Patrick, departments of Biochemistry and Paediatrics, University of Ottawa, Ottawa, Ont.; Reginald S. Sauvé, Department of Paediatrics, University of Calgary, Calgary, Alta.; Johnny E.E. Van Aerde, Department of Pediatrics, Walter MacKenzie Centre, Edmonton, Alta.; Andrée M. Weber, Department of Paediatrics, Hôpital Sainte-Justine, Montreal, Que.; and Stanley H. Zlotkin, Division of Clinical Nutrition, Hospital for Sick Children, Toronto, Ont. Consultants: Drs. Ranjit K. Chandra, Department of Paediatrics, Janeway Child Health Centre, St John's, Nfld.; Anthony Myres, Environmental Substances Division, Department of National Health and Welfare, Ottawa, Ont.; Paul B. Pencharz, Division of Clinical Nutrition, Hospital for Sick Children, Toronto, Ont.; and Claude Roy, Department of Paediatrics, Hôpital Sainte-Justine, Montreal, Que. Liaisons: Ms. Marianne Antoniak, president, Canadian Infant Formula Association, Toronto, Ont.; Dr. Margaret Cheney, Bureau of Nutritional Sciences, Health Protection Branch, Department of National Health and Welfare, Ottawa, Ont.; Ms. Patricia Coulter and Ms. Donna Secker (Canadian Dietetic Association), Nutrition and Food Service Department, Hospital for Sick Children, Toronto, Ont.; Dr. A. George F. Davidson (Human Milk Banking Association of North America), Department of Paediatrics, British Columbia's Children's Hospital, Vancouver, BC; Ms. Suzanne Hendricks (president) and Dr. Nancy Schwartz, National Institute of Nutrition, Ottawa, Ont.; Dr. Ronald Kleinman (American Academy of Pediatrics), Pediatric Gastrointestinal and Nutrition Unit, Massachussetts General Hospital, Boston, Mass.; Ms. Dawn Walker, Family and Child Health, Health Services and Promotion Branch, Department of National Health and Welfare, Ottawa, Ont.; and Dr. David Yeung, manager of nutrition research, H.J. Heinz Company of Canada, North York, Ont.

Disclaimer

The recommendations in this position paper do not indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate.