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. 1999 Jun 12;318(7198):1625. doi: 10.1136/bmj.318.7198.1625

Early diet in preterm babies and later intelligence quotient

Surely study showed that breast milk is feed of choice for premature babies

Deborah Behrman 1, Mary Broadfoot 1,a, Phyll Buchanan 1, Carolanne Lamont 1, Magda Sachs 1
PMCID: PMC1115985  PMID: 10364137

Editor—Lucas et al’s paper on early diet in preterm babies and their later intelligence quotient (IQ)1 sparked intense media interest: “Premature babies need enriched diets,” said the BBC.2 The authors didn’t point out any of the known advantages of breast milk for premature babies.

The paper compared babies who received only infant formula with babies who received breast milk and infant formula. Babies received either standard term formula or preterm formula. The main outcome, IQ at age 7-8, showed no advantage for preterm formula. Subgroup analyses looked at results for boys and girls. Few details were given about how successful the randomisation was in terms of the sex of the baby in relation to weight. Is it then valid to draw separate conclusions for boys and girls?

We suggest that the following conclusion would be more accurate: “Breast milk continues to be the feed of choice for premature babies. The results did not show an advantage for preterm formula in terms of cognitive performance at 7½-8 years. Further work with a cohort randomised by sex would be of interest.”

Publication of this study seems to have been delayed. The last data must have been collected in 1992—and indeed were used in a paper published in that year.3 If the study had contained anything to change practice it should have been published as soon as the results were known.

Breast feeding is the physiological norm for infants. Any other method of feeding babies must be assumed to be risky until proved otherwise. The onus is on researchers to prove that substitutes are both safe and beneficial. Indeed, it is recommended that all research studies on infant feeding should include a breast feeding reference group to put the findings into context.4 When research compares two breast milk substitutes, neither one can be concluded to be safer or better than breast milk. When the sponsors of research stand to gain from increased sales of infant formula, readers must be aware of the conflict of interest.

Researchers and reporters have a responsibility to parents and babies. Headlines such as “Premature babies need enriched diets” can undermine women. It would confirm the work of health professionals and lay workers, and support parents providing breast milk for their babies, if press releases concerning infant feeding reiterated the simple message that “breast is best.”

References

  • 1.Lucas A, Morley R, Cole TJ. Randomised trial of early diet in preterm babies and later intelligence quotient. BMJ. 1998;317:1481–1487. doi: 10.1136/bmj.317.7171.1481. . (28 November.) [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.BBC News, 26 November 1998, Health. Premature babies need enriched diets. http://news.bbc.co.uk/hi/english/health/newsid%5F222000/222453.stm
  • 3.Lucas A, Morley R, Cole TJ, Lister G, Leeson-Payne C. Breast milk and subsequent intelligence quotient in children born preterm. Lancet. 1992;339:261–264. doi: 10.1016/0140-6736(92)91329-7. [DOI] [PubMed] [Google Scholar]
  • 4.Committee on Medical Aspects of Food and Nutrition Policy. Guidelines on the nutritional assessment of infant formulas 47. London: Stationery Office; 1996. [PubMed] [Google Scholar]
BMJ. 1999 Jun 12;318(7198):1625.

Authors’ reply

Alan Lucas 1,2,1-2002, Tim Cole 1,2, Ruth Morley 1,2

Editor—Behrman et al disappoint us, since we have provided as much evidence as any other authors, internationally, supporting breast milk for neonatal care. Our preterm studies, suggesting that breast milk reduces necrotising enterocolitis, systemic sepsis, and feed intolerance and promotes neurodevelopment, have strongly influenced mothers to provide their milk.1-1–1-4 We recommend that mothers of preterm infants be counselled to provide breast milk on health grounds. Against this, any implication that our study was biased towards promoting sales of infant formula is misplaced.

Behrman et al miss the point. They say that the claim that premature babies need enriched diets undermines women. What mothers readily appreciate, given proper explanation, is that it is undermining to the health of premature babies not to receive their special nutritional requirements. We cannot suppose that human milk evolved to feed babies born up to four months too soon, too immature to feed, who would have died before modern care. Had these babies remained in utero they would have been fed via the placenta; thus no enteral feed—breast milk or formula—is “physiological” for them.

As it happens, objective research strongly favours human milk, but not as a sole source of nutrition. Substantial work over 50 years shows that preterm infants have special nutrient needs—for instance, the brain at 28 weeks’ gestation is growing 2.5 times faster than the brain at term.1-5 Their rapid growth, bone mineralisation, and need to establish tissue nutrient stores often require fuelling by the additional use of specialised nutritional products.1-5 Moreover, special formulas are essential when mothers express insufficient milk.

Behrman et al should re-examine our paper to resolve their misunderstanding of the randomised groups and reappraise our justification for subgroup analyses. They infer incorrectly that our database was complete by 1992. Our paper described a randomised study providing evidence of serious consequences of feeding preterm infants suboptimally. These data should not, however, undermine the use of expressed breast milk for premature babies or the establishment of breast feeding, both of which occurred in our study population.

Supporters of breast feeding must appreciate that standard public health advice and campaigns relevant to healthy full term infants cannot be applied to the complex hospital care of premature babies. Any advocacy role undertaken by this or any similar organisation must be backed by a medical understanding of this special circumstance.

References

  • 1-1.Lucas A, Cole TJ. Breast milk and neonatal necrotising enterocolitis. Lancet. 1990;336:1519–1523. doi: 10.1016/0140-6736(90)93304-8. [DOI] [PubMed] [Google Scholar]
  • 1-2.Lucas A. Feeding low birthweight infants. In: Roberton NRC, editor. Textbook of neonatology. 2nd ed. London: Churchill Livingstone; 1992. pp. 279–288. [Google Scholar]
  • 1-3.Lucas A, Morley RM, Cole TJ, Lister G, Leeson-Payne C. Breast milk and subsequent intelligence quotient in children born preterm. Lancet. 1992;339:261–264. doi: 10.1016/0140-6736(92)91329-7. [DOI] [PubMed] [Google Scholar]
  • 1-4.Lucas A, Fewtrell M, Morley R, Lucas P, Baker B, Lister G, et al. Randomized outcome trial of human milk fortification and developmental outcome in preterm infants. Am J Clin Nutr. 1996;2:142–151. doi: 10.1093/ajcn/64.2.142. [DOI] [PubMed] [Google Scholar]
  • 1-5.Tsang R, Lucas A, Uauy R, Zlotkin S, editors. Nutritional needs of the preterm infant. Pawling, USA: Caduceus Medical; 1993. [Google Scholar]

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