Breast feeding reduces morbidity

BMJ 1999; 318 doi: https://doi.org/10.1136/bmj.318.7194.1303 (Published 15 May 1999) Cite this as: BMJ 1999;318:1303

The risk of HIV transmission requires risk assessment—not a shift to formula feeds

  1. Michael C Latham, Professor of international nutrition.
  1. Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853-6301, USA

    Papers p 1316

    It is time that doctors, and everyone else, accepted breast feeding as the biological norm, in terms of both feeding and caring for human infants. Exclusive breast feeding for six months provides the newborn with all the essential nutrients for health and growth and anti-infective properties not present in breastmilk substitutes.1 The American Academy of Pediatrics recently stated, “The breast fed infant is the reference or normative model against which all alternative feeding methods must be measured.”2 Therefore our vocabulary needs to change,3 and we should be saying that formula fed babies have more diseases and poorer psychological development than normal babies, rather than that breast fed babies have less disease and higher intelligence. This longstanding view is, however, under threat from the fact that HIV may be transmitted from mother to child through breast milk.

    For several decades we have known that artificially fed infants have much higher rates of morbidity and mortality than those who are breastfed. Breast milk contains immunoglobulins, phagocytes, T lymphocytes, enzymes such as lysozymes, and many other factors which help protect the infant against infections,4 including cells, antibodies, hormones, and other important constituents not present in infant formula. In this week's BMJ César et al provide a reminder of this in their study from Brazil showing that breast feeding protected infants against pneumonia—a leading cause of death in young children in the developing world (p 1316).5 Theirs was a nested case-control study comparing 152 infants admitted to hospital and diagnosed by referees to have had pneumonia and 2391 population based controls. The authors report that infants not receiving breast milk were 17 times more likely to present with pneumonia than those receiving breast milk but no artificial milk. The relative risk for babies aged under 3 months was 61.

    Though these are impressive results, the study does have some problems. This type of research design can be flawed because there can be many confounding variables.6 The authors controlled for some of these, but not all. A more serious concern is the relatively small sample size, with the result that very few “cases” were exclusively breast fed—20% in the first month and 1.6% at six months. The literature suggests that exclusive breast feeding produces greater reductions in morbidity and mortality than partial breast feeding.7 Despite the small numbers of cases in the three feeding categories, especially in the “only maternal milk category,” and in each age group, the authors still get highly significant differences. Their results indicate that breast feeding protects infants against pneumonia at all ages, but that the protection is much greater in younger infants.

    This research is timely because of its wide policy implications. Years of successful work to protect, support, and promote breast feeding and stem the spreading use of commercial breast milk substitutes in developing countries8 is now threatened because of concern about HIV transmission in breast milk. There is a small risk that an HIV positive woman will infect her infant through breast feeding.9 However, the bigger risk is that there will be an inappropriate rush to replace breast feeding with formula feeding by women who have HIV, or think they might have HIV, in high prevalence areas in developing countries. There may also be a large spillover of formula feeding to mothers who do not carry the virus.

    HIV is particularly prevalent in sub-Saharan Africa, and ministries of health in those countries are under pressure from several sources to provide free, or subsidised, infant formula for mothers infected with HIV. It needs to be recognised that most babies with HIV were infected in utero or during childbirth, not through breast milk.10 Indeed, there is new evidence to show that in babies who are exclusively breast fed transmission of HIV from breast milk was very low, at least in the first three months of life.11

    Pregnant women have a right to HIV testing and to know or not know the test results. Poor women in African countries who know they are HIV positive have a difficult infant feeding choice and need to be counselled about the risks of each option. The World Health Organisation, the United Nations AIDS Agency, and Unicef have stated that the “most effective method of preventing breast milk transmission of HIV is breast milk avoidance.” They have, nevertheless, recognised that when mothers do not have assured, uninterrupted access to breast milk substitutes that can be safely prepared and fed, and “where infectious diseases and malnutrition are the primary causes of death during infancy … then artificial feeding substantially increases children's risk of illness and death.”12 The Brazilian study provides new and impressive evidence on these serious increased risks of one such disease, pneumonia, in artificially fed infants.

    The conditions necessary for adequate and safe formula feeding unfortunately exist for only a tiny minority of HIV infected women in Africa. Mothers live in poverty and have poor access to decent health care, safe water, good hygiene, fuel, and secure supplies of breastmilk substitutes. In the end decisions need to be made on the basis of risk assessment. Moreover, too much attention is given to formula feeding as the best alternative to breast feeding for HIV infected women. Alternatives for women who opt not to breast feed as normally advised include a shorter total duration of breast feeding; more emphasis on exclusive breast feeding; heat treatment of the mother's own expressed breast milk to kill the virus; donations of breast milk by non-infected mothers; milk banking or wet nursing; and use of modified animal milks.8

    Will the commercial manufacturers of breast milk substitutes take advantage of the AIDS pandemic to peddle their products under the guise of humanitarian concern? The UN agencies agree that the international code of marketing of breast milk substitutes must be respected and that no free donations of breast milk substitutes should be provided by these corporations through the health care system.13 But many of the major corporations have never fully respected the code.14 Studies like those of César et al remind us why the code is important.


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