White blood. A little extra something - part 2
Breast milk is white blood
Breast milk is a living tissue. It has been known in some cultures as white blood. Breast milk is extraordinarily complex, an exquisitely dynamic and elegant biological system, designed over two hundred million years of evolutionary history to nourish and protect the nascent mammalian organism.
1. Nutritional sustenance
Nutritional sustenance with species-specific proteins, lipids, lactose, and a wide variety of identified and yet to be identified vitamins, minerals, trace elements and micro-nutrients is just one of the significant functions of breastmilk.
The Wyeth ad for the commercial milk formula known as S26, running in the medical news and journals that I browse through every week, states: "We believe that when it comes to infant nutrition, every little bit counts." They are counting the bits, adding the bits, subtracting pieces, modifying, refining.
Industry found, for example, that formula contained too much salt when babies presented to us with convulsions, renal and brain damage. They found that formula contained too little iodine when babies presented with goitre. They found that formula contained too little zinc when babies presented with skin lesions, impaired growth and brain damage; too little chloride when babies presented with metabolic alkalosis, renal and brain damage. They found that formula contained too much phosphorous when babies presented with convulsions; too little pyridoxine, when babies presented with convulsions and brain damage. Excess iron load in formula has resulted in pathogenic gut flora and iron-deficiency anaemia due to microscopic hemorrhage; not enough iron has caused anaemia, and chancing on the right level is difficult due to the many variables that affect iron’s bioavailability.
The more commercial milk formula is refined, "humanised", the more unknown bits of trace elements and micro-nutrients are lost, with unknown consequences. The bovine whey/casein ratio has been altered to mimic the low protein levels of human milk, but this results in higher levels of plasma amino acid and serum urea nitrogen than the older whole milk formulas. Wyeth writes, in their ads for doctors: "It's just another example of our commitment to give you a little extra something."
2. Augmented bioavailability of nutrients
Breast milk is living tissue.
Complementing the immature human organism's capacity to utilise these nutrients is another inimitable biological function, aided by seventy-odd enzymes (including mammary amylase and lipases) and by bile salts, nucleotides, polyamines, prostaglandins and a variety of transfer factors. There are complex interrelationships between the hundreds of components of breast milk and countless complex interrelationships between these components and the biochemistry of the infant's gut and intestinal mucosa.
3. Immune protection
The third irreproducible quality of breast milk is protective. Breast milk has the same kinds of white cells as we find in blood. Three classes of antibodies are found in abundance in human milk, including breast milk's bespoke antibody superpower, secretory IgA, ingested many times day and night by the baby.
As well as providing active protection to the baby by responding dynamically to maternal exposure to pathogens, breast milk is immunomodulatory. Secretory IgA shapes the baby's gut microbiota and immune system, promoting friendly bacteria, resisting pathogens, potentially affecting host gene expression and protecting against inflammatory diseases. Breast milk lymphocytes too are incorporated into the suckling's own tissues. Breast milk belongs to the enteromammary and bronchomammary immune systems, which contemporaneously immunise the baby to pathogens contacted by the mother's respiratory or intestinal mucosa. It is rich with anti-inflammatory factors and myriad other non-specific immunologic factors. It contains its own dynamic microbiome, part of the mammary and mother-infant immune systems.
It is not surprising, then, that even in the west, formula-feeding increases the finding of potentially pathogenic Haemophilus influenze colonisation in infants' throats; significantly increases the incidences of otitis media and risk of hospitalisation for serious respiratory illness in infants, such as wheezing, bronchiolitis, pneumonia; and is linked with increased risk of asthma, diabetes, and atopic dermatitis compared to exclusive breastfeeding.
Commercial milk formulas increase infants' risk of gastrointestinal illness in low, middle and high income countries. Cow's milk specifically promotes proliferation of the coliform and putrefactive bacteria necessary in the gut of a ruminant animal. These same organisms disrupt microbiome development in the gut of a human baby, demonstrated most frighteningly by the increased risk of necrotising enterocolitis linked with bovine-derived milks in preterm infants.
Although the mechanisms are not clear, not breastfeeding is also associated with increased maternal risks of breast cancer, ovarian cancer, type 2 diabetes, hypertension and heart disease.
4. Modulation of growth
Breastmilk is, fourthly, growth modulatory, containing high concentrations of growth factors and numerous hormones to complement the immature endocrinological system of the baby.
5. Dynamic composition
The fifth essential quality of human milk is its dynamic composition, regulated by the baby according to age and need. The detail of stage-related specificity is astonishing. Premature milk, colostrum, transitional milk, mature milk and weaning milk have substantially different concentrations of various proteins, fats, antibodies, white cells and micro-nutrients to meet the age-related requirements for optimal function and health. The milk at the end of a breastfeed is up to four or five times more caloric dense than milk at the beginning, and the milk in one breast may differ to the milk in the other, depending on the use an infant makes of each breast: milk varies over a feed, over a day and over the months.
Is the use of commercial milk formula the largest medical experiment of the past century?
Formula is unchanging. Formula is dead. Powder spooned from a tin or a pre-prepared liquid will never reproduce the innately living nature of human tissue, will never be "nearly as good as" the intricately dynamic, powerfully bioactive ecosystem of breast milk.
Perhaps this is why, when claiming that S-26 is "close to breast milk in many ... important ways", Wyeth fails to mention the four that are living and inimicable out of the five critical functions of human milk. The creation of breast milk is as much beyond the scope of adding and subtracting "bits" as a currawong is beyond the manufacturers of aeroplanes, as a kidney is beyond the manufacturers of dialysis machines. These ads will be tossed out of the advertising department of our medical journals one day, because they are irresponsible.
Neither the Australian Lactation Consultants Association, the Nursing Mothers Association of Australia, nor other breastfeeding advocacy organisations can afford to run hundreds of advertisements costing many thousands of dollars each in our weekly magazines and journals this year, telling us repeatedly with succinct headlines and eye-catching photographics of the important research about the deleterious effects of breastmilk substitutes on human health.
Breast milk substitution may be the largest invivo medical experiment of all time, an experiment propagated on global scale over the last century. Just as insulin was initially extracted from the pancreas of a cow or pig and highly purified, just as digoxin has been manufactured from the leaves of Digitalis purpurea, foxglove, a wise woman's herb, so a commercial milk formula is a product extracted from the udder of a cow and processed and modified. It is an engineered infant food.
Commercial milk formuila saves lives when breastfeeding is unworkable, and when it is difficult for parents to access donor human milk (which is usually the case for parents, because governments and health systems do not seriously prioritise human milk for human babies). It helps us nourish our infants in a complex 21st century world, which has profound health system blind spots about how to best to prevent or help breastfeeding problems, in which increasing numbers of women face metabolic challenges with mammary gland effects, beginning in childhood. In the real world, mixed feeding helps women continue to breastfeed their babies. But commercial milk formulas are medically engineered products which cannot replicate the living human tissue of breast milk.
In a just world, families would have safe and easy access to donor milk when it was needed
In a just and ecologically responsible world, appropriately resourced human milk banks would be widespread and accessible, so that other mothers' milk, the safest option, can be used before resorting to breastmilk substitution. In a just and ecologically responsible world, formula would be manufactured under stringent government regulation and available without cost to the infants who need it, as a last resort when properly regulated donor milk is not available.
Not only lives spared, but significant downstream savings to the health system from the deleterious effects of formula use on both maternal and infant health would rapidly justify such use of the medical and research dollar.
I wrote the essay A little extra something when I lived in Bullaburra, in the Blue Mountains. My children were very young. It took me a good six months and I thought about it day and night. I wrote it in response to Wyeth's advertisements for commercial milk formulas which were appearing regularly across a range of medical journals and in the medical news at that time. As a GP, I couldn't escape these ads: they were everywhere in the professional materials I accessed. In every spare moment, when my children were asleep or in someone else’s care, I sat in my cramped study overlooking the wild green Bullaburra gully with its raucous flocks of sulphur-crested cockatoos, dreaming and writing, writing and dreaming, urgently. ...Then when I finished it in August 1994, I didn’t publish it. I had no idea who might be interested. I’ll never forget that Maureen Minchin kindly read every word and told me down the phone that she really liked it. After we hung up, I shouted out with happiness into the bright gully air. This is an updated excerpt.
Recommended resources
Breastfeeding durations in ancestral environments. A little extra something - part 3
In the land between lands, roots of flesh and tides of soul entwine. A little extra something - part 4
Mamma, mother: the Earth is crying. A little extra something - part 5
Selected references
Donald K, Petersen C, Turvey SE, Finlay BB, Azad MB. Secretory IgA: Linking microbes, maternal health, and infant health through human milk. Cell Host Microbe. 2022 May 11;30(5):650-659. doi: 10.1016/j.chom.2022.02.005. PMID: 35550668.
He X, Tinghäll Nilsson U, Mishchuk DO, Hernell O, Lönnerdal B, Hartvigsen ML, Jacobsen LN, Kvistgaard AS, Slupsky CM, Karlsland Åkeson P. Impact of formula protein quantity and source on infant metabolism: serum, urine, and fecal metabolomes of a randomized controlled study. Am J Clin Nutr. 2025 Apr;121(4):853-864. doi: 10.1016/j.ajcnut.2025.02.002. Epub 2025 Feb 5. PMID: 39921093.
McClellan HL, Miller SJ, Hartmann PE. Evolution of lactation: nutrition v. protection with special reference to five mammalian species. Nutrition Research Reviews. 2008;21:97-116.
Oftedal O. The evolution of milk secretion and its ancient origins. Animal. 2012;6(3):355-368.
Veille A, Miller V. Duration of breast feeding in ancestral environments. In: Shackelford TK, Weekes-Shackelford VA, editors. Encyclopedia of Evolutionary Psychological Science. https://doi.org/10.1007/978-3-319-19650-3_818 Springer, Cham; 2021. p. 2152.
Victora CG, Bahl R, Barros AJD, Franco GVA, Horton S, Krasevec J, et al. Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect. Lancet. 2016;387:475-490.
