Breastfeeding and iron status

“Anemia in the breastfed baby is uncommon for the following reasons:

“The healthy full term infant has ample iron stores at birth, enough to last for at least 6 months of life,

“Iron in human milk is well absorbed -- 49 per cent as opposed to 10 per cent from cow's milk and 4 per cent from iron-fortified formula. The high lactose and vitamin C levels in human milk aid the absorption of iron.

“Breastfed babies do not lose iron from their bowels, as do babies who are fed in cow's milk, which has been shown to cause intestinal fissures.”

--The Breastfeeding Answer Book(10), La Leche League

Breastmilk:
The perfect nutrition

In Canada and other industrialized countries, breastfeeding has often been maligned for being a contributing factor to iron deficiency during infancy. Frequent references to human milk as being low in iron are found in infant feeding recommendations and in parent literature instruction on infant feeding. Literature on infant feeding produced by the infant food industry, both infant formula and complementary foods, tend to exploit parental concerns of is my baby getting enough iron? Concerns about iron deficiency are real, but to exploit parents with alarmist propaganda to promote artificial feeding can be hazardous.

Many questions need to be asked concerning the efficacy and safety of current Canadian infant feeding and iron recommendations and practices. First we need to ask which populations are at risk for iron deficiency. Two studies come to mind. Lehman and Gray-Donald(1), report on the prevalence of iron deficiency anemia in a population of disadvantaged infants in Montreal. Breastfeeding was started by only 17 per cent of 220 mothers participating in the study, and by 4 months only 6 per cent were receiving breastmilk (no mention is made of exclusive breastfeeding). Artificial feeding of various forms was practised by this population -- some whole cow’s milk, some routine or fortified formula, some had started iron fortified cereals at one month. Thus, in a population with very poor breastfeeding rates, the prevalence rate for low serum ferritin levels was 25 per cent. Interestingly, the failure to consume iron fortified formula was not associated with an increased risk of anemia. This study, funded by Ross Laboratories, recommends supplying free fortified formula to underprivileged children and makes no mention of promoting and supporting breastfeeding for high needs mothers and their infants. Surprisingly, the Canadian Pediatric Association (CPA) recommendations for fortified formulas from birth are justified on the basis of this study.

Elsewhere Greene-Finestone and Feldman(2) randomly selected 320 mothers from the discharge records of four Ottawa hospitals. Breastfeeding (not defined to be exclusive) was initiated by 76 per cent. The iron deficiency prevalency was 18.7 per cent for those who never breastfed, 14.4 per cent for those who breastfed for less than 6 months and 10.7 per cent for those who breastfed for six months or more. They concluded iron deficiency to be relatively low risk in a general population where breastfeeding rates are high, parents have accessible universal health care, and reliable sources of iron rich complementary foods are available. The protective effect of breastfeeding was attributed to the high bioavailablility of breastmilk iron (49 per cent).

Are current recommendations scientific?

The controversial CPS infant feeding recommendations, Meeting the iron needs of infants and young children: an update(3), has resulted in confusion and problems in infant feeding management since its publication in 1991. Data to determine whether full term healthy infants are at risk is lacking and science-based data to support the recommendations are inadequate. Moreover, the subtle inclusion of breast-feeding for more than six months without supplemental iron, as a risk factor gives incorrect onus. This statement, much like the infant formula promotions, uses cow’s milk to compare the virtues of fortified formulas. The alarmist tactics of gastrointestinal bleeding from the gut and the low levels of iron found in cow’s milk only leads to confusion (after all isn’t routine formula made from cow’s milk?) and must be seen as a diversionary tactic to prevent making the real comparisons to breastmilk. Given the overwhelming evidence that breastmilk provides the best form of readily absorbable iron in the right format and amounts, why is breastfeeding given so little merit in their recommendations? Shouldn’t the first recommendation be to ensure support to enable all mothers to breastfeed?

Another recent alarmist review of infant needs for iron, Ziegler and Fomon(4), two prominent US infant nutritionists, claim, in the industry-funded Nutrition Reviews, that “the need for absorbed iron during the first year of life is so great that satisfactory iron nutritional status can be assured only with the aid of iron fortified foods or use of medicinal iron supplement”. They continue “iron-fortification of infant formula offers a highly effective means of providing adequate amounts of available iron. Iron added to formula reaches a large population of infants, it is safe, free of known hazards, and well accepted”. Junk science surely!

And what about the recommendation to start all artificially fed infants on iron fortified formula from birth? Full term infants have sufficient stores of iron to last for the first six months of life. And what about the risk of infections? Studies show that iron fortification may increase the susceptibility of infection(5,6)

Scientific studies too, frequently put the burden of proof on breastmilk to determine its adequacy, rather than the artificial alternative. Questions about conflict of interest also need to be raised. Much of the research into the iron needs of infants during the first year of life is funded by the infant feeding products industry and can be perceived to have a goal of creating markets for products. Is the fear of iron deficiency used as a vehicle for marketing iron-enriched products? Is the fear of inadequate iron used to discredit breastmilk by labelling it “low in iron”? Low by what criteria? Should the decision to supplement be influenced by product marketing and labelling?

More is not better

Are artificially fed infants at risk for receiving too much iron from birth through supplementation and/or fortification of baby milks and complementary foods? Iron is a powerful pro-oxidant that might do damage in excess, and a high level of iron in complementary foods has been shown to interfere with the absorption of other minerals (zinc and copper)(7). What are the nutritional and biochemical consequences of infants receiving large amounts of exogenous iron from birth to 12 months? Is there enough research to prove the safety, both in the short term and in the long term, of routine supplementation? How much iron is enough? Is more better? In North America the usual iron content is 12mg/l, while in Europe the level is 7mg/l. Levels of 4mg/l have been shown(7) to be adequate. How is iron absorbed? An American Journal of Clinical Nutrition editorial(8) recently asked how little is known about the absorption of iron and how little about the mechanisms that manage the proper balance between supply and need, when too much can cause tissue damage -- cirrhosis of the liver, cardiomyopathy, diabetes, and anthropathy -- too little can result in anemia.

Many of these questions remain unanswered, yet “professional” recommendations for fortification and supplementation are the order of the day. Clearly much research needs to be done to adequately address safety and adequacy concerns that both parents and health care workers may have.

Parents of exclusively breastfed infants can certainly put these anxieties aside. Research in the iron status of exclusively breastfed infants, documents adequate intakes for well over six months.(9)

References

1. Lehman, F. et al. Iron Deficiency anemia in 1 year old children of disadvantaged families in Montreal. Can Med Assoc J. 146: 1571-1576,1992 BACK

2. Greene-Finestone, L. et al. Prevalence and Risk Factors of Iron Depletion and Iron Deficiency Anemia among Infants in Ottawa-Carleton. J. Can. Diet. Assoc. 52:20-23, 1991 BACK

3. Canadian Pediatric Society. Meeting the iron needs of infants and young children: an update Position Statement by the Nutrition Committee. Can Med Assoc J;144:1452-1453, 1991 BACK

4. Ziegler, E. E. and Fomon, S. J. Strategies for the Prevention of Iron Deficiency: Iron in Infant Formulas and Baby Foods. Nutrition Reviews 54:348-354,1996 BACK

5. Weinberg, E.D. Iron and susceptibility to infectious disease. Science;184: 952-956, 1974 BACK

6. Haddock, R.L. et al. Infant Diet and Salmonellosis. Am J Publ Health;81:997-100013, 1991 BACK

7. Lonnerdal, B. Hernell, O. Iron, zinc, copper and selenium status of breast-fed infants and infants fed trace element fortified milk-based infant formula. Acta Pediatrica. 83:367-373,1994 BACK

8. Beutler, E. How little we know about the absorption of iron. Am J Clin Nutr 66:419-420,1997 BACK

9. Pisacane, A. et al Iron status in breast-fed infants. J.Pediatr 127:429-341,1995 BACK

10. Mohrbacher, N. Stock, J. The Answer Book La Leche League International, Shaumburg, Illinois. p.144, rev. 1997 BACK