It seems to widely agreed now that full term babies usually do fine
regarding their iron status for six months if predominently breast-fed
(using the WHO definition). What happens if they are exclusively breast-fed
has presumably not been studied, as so few researchers have used careful
definitions and so few babies are exclusively breast-fed for that long. It
may be the case that additions of almost anything to the infant diet affect
absorption of iron from breast milk, and thus exclusively breast-fed
infants may well on average do well for longer than six months. In one
Finnish study, "exclusively" breast fed infants did better than those fed
iron fortified cereals until 6 months of age at which time those still not
receiving solids declined until by nine months of age they were at about
the same level as the supplemented infants. However, 6/36 were removed from
the study before 9 months of age and given supplementary iron due to signs
of iron deficiency (not anemia though). Ref: Siimes MA et al. Exclusive
breast-feeding for 9 months: risk of iron deficiency. J Pediatr
104:196-199, 1984. JA McMillan et al (Iron sufficiency in breast-fed
infants and the availability of iron from human milk. Pediatrics
58:686-691, 1976) followed 4 infants until 18 months of age and found no
serious iron deficiency. RA Pastel et al (Iron sufficiency with prolonged
exclusive breastfeeding in Peruvian infants. Clinical Pediatrics 20:625-6,
1981) found no sign of iron deficiency in seven exclusively breast-fed
Peruvian infants age 7.5-12 months (mean 9.3). Many other studies have
arrived at a less positive estimation of the relationship between
breastfeeding and infant iron status, but all that I have seen either paid
little attention to what supplements were given or, though they claimed the
infants were exclusively breast-fed, did not check this carefully enough to
convince one that this was indeed the case. More research is needed on this
as for many other outcomes, among infants fed nothing but human milk for
varying periods of time.
Ted Greiner, PhD
Senior Lecturer in International Nutrition
Unit for International Child Health, Entrance 11
Uppsala University
75185 Uppsala
Sweden

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