The Crucial Considerations

Human milk poses none of the testing, marketing or distribution problems of new foods.  Lactation is one of the most ancient mammalian characteristics -dating back some 200 million years to the earliest egg-laying species, and hence preceding the evolution of placental gestation.

In man, the consumption of animal milk is relatively recent, dating back less than 10,000 years; even today animal milk forms a culturally acceptable part of the diet for only some of mankind.

The widespread use of infant formulas based on cow's milk in the Western world is a development of only the last 50 to 70 years, made possible by revolutions in dairy farming and food technology.

Protection

Much illness in early childhood, especially in developing countries, is related to infection, which occurs more easily in children with PCM and which in turn makes malnutrition worse.

The considerable protective effect afforded by breast feeding has been recognized for decades, but has been considered to be related simply to cleanliness and lack of opportunity for contamination.

However, recent work has demonstrated that human milk has anti-infective properties, because of the presence of secretory immunoglobulin A, lysozyme, the bifidus factor, lactoferrin, and other substances.  The protective effect of milk is evident especially in relation to intestinal infections, including diarrheal disease due to "Escherichia coli" and other organisms, enteroviruses, and moniliasis .

Also, the biologically normal continuation of lactation into the second year or later (currently termed "prolonged"breast feeding) supplies a small, but significant, supplement to the critical weaning or transitional diet, and hence assists in the prevention of kwashiokor.

Conversely, infantile obesity i s much more common in bottle-fed infants in communities where home hygiene is good and the purchase of formula not limited by funds. The quantity and composition are under the mother's control, so that calorie over dosage can occur.

By contrast, breast feeding is a supply and demand phenomenon involving only the nursing dyad, with the volume regulated by the infant's appetite and thirst.

Nutrition

All mammalian milks have highly specific biochemical compositions.  The complexity of the nutrients present in human milk has been under emphasized in pediatric textbooks, where comparisons of the proximate principles-protein, fat, and lactose-are usually the most that are given.

In the case of human milk, the most significant of the many differences from cow's milk appears to be the abundant supply of nutrients most needed for the rapid growth and development of the central nervous system, including the brain.  Particularly high levels of lactose, cystine and cholesterol, and specific patterns of polyenoic fatty acids are found in human milk. 

"Breast milk is the original convenience food. No mixing, warming, or sterilising needed; no dirty pots and bottles to wash up after wards; always on tap from its specially designed unbreakable containers.  And it is genuinely the most nutritious wholesome product on the market.  A copy-writer's dream."

Mike Muller, The Baby Killer, England 1974 

Contraception

Recent studies indicate that the traditional belief that unsupplemented breast feeding has a contraceptive, child-spacing effect is true, and is related to the anovulatory effect of prolactin (and other hormones) secreted by the anterior pituitary in response to the baby's sucking.  The existence of this biological system is not surprising, as it parallels the spacing of offspring that occurs in other mammals as a consequence of mating or rutting seasons.

from "Human Milk, Nutrition and the World Resource Crisis", by D.B. Jelliffe and E.F. Jelliffe, in Science, USA, May 1975

Editorial Note:

Breast feeding is not in itself a totally reliable contraceptive, as indicated by the origin of the word "kwashiorkor", which means the disease which affects the first born if the mother gets pregnant again while breast feeding.  This means that there is a need to use contraceptive methods to protect breast feeding and prevent protein-energy malnutrition.