Evidence streams in infant feeding: ex-debate

Maureen MinchinAllergies, Book Reviews, Bottle Feeding, breastmilk, Child Health, debate, epigenetics, Food Intolerance, General News, Immunology, Infant Formula, Infant Health, Lactation, Maternal Health, Milk Hypothesis, Milk Matters

Breastfeeding has become the centrepiece of public health programmes, endorsed by the health industry and the infant formula industry and philanthropic groups and national governments alike. How did the world arrive at that global consensus about the importance of breastfeeding? It developed from three related, but independent, streams of evidence.

1. The first stream flows from the results of some true RCTs in preterm infants. These were possible because of the determined state of Anglophone ignorance at the time, and the felt need to prove scientifically what feeding method was safest for the most vulnerable children. (And the answer is no surprise: clearly, maternal milk appropriately supplemented if need be. The average IQ advantage to the lucky minority of preterm infants who went home breastfeeding was a whopping 12 points. And the mothers’ choice to breastfeed or not made no difference to outcomes. The babies of those who wanted to, but were not able to, breastfeed did no better than those who did not want to breastfeed. All adjusted for confounders. These studies included the use of low-fat donor drip milk, not individually-tailored maternal or lactose-engineered breastmilk. Scandinavian units had been using only breastmilk for some time before these trials. More about all this in Milk Matters, of course. )

No further RCTs such as these can ethically be done as too many vulnerable babies died or were damaged lifelong. I believe that the evidence about NEC is so strong, and so old, that a lawsuit alleging negligence in cases of deaths or injury from NEC could succeed. (NEC is necrotising enterocolitis, which is gut gangrene, basically). Hospitals that do not provide maternal or donor milk may face class actions.

Professor Alan Lucas summarises these preterm studies in Nestlé Nutrition Institute Workshop Vol 90, Human Milk: Composition, Clinical Benefits and Future Opportunities, saying “Unexpectedly diverse immediate beneficial effects have been shown for cognition, brain structure, risk factors for CVD, structural development of the heart and lungs, bone health, and atopy. These data add much weight to the evidence obtained in full-term infants using observational study designs, that human milk feeding in early life may fundamentally and permanently change the biology of the organism. Breastfeeding is emerging as a major evidence-based field of medical and public health practice.” Strong words from an expert with his name on formula patents.

2. The second body of evidence is the results of small and large observational studies and population-based epidemiological analyses and meta-analyses since the 19th century, which even after controlling for confounders, persist in showing
o short and long-term health and development differences that favour breastfed over formula-fed children, including significant differences in organ size and structure, and
o health differences between mothers who have breastfed or not,
*over differing time periods,
*in dozens of different countries and cultures,
*across many decades, and
*despite hundreds of changes to multiple brands

3. The third body of evidence is the recent spectacular advance in the knowledge of mammalian milk, and the ways it affects the development of the species’ young. No informed scientist would disagree that “When the mother breastfeeds her baby…she is transferring a wealth of bioactive molecules that will influence her baby’s immune system, developmental patterns and eventual adult physiology.” But there are drongos who feel free to scoff at findings of awarding-winning scientists like Professor Katie Hinde – even though thanks to Professor Donna Geddes, we have clear visual ultrasound evidence of the limited backwash into the breast the baby feeds, meaning the child’s saliva can influence the breast microbiome. (Other well-proven pathways also exist, of course, and mothers’ kissing and nuzzling their babies and gobbling their fingers is as protective as it is instinctive.)

Scientists are identifying causal pathways fr milk’s biological effects. As BC Melnik says, “Milk is not ‘just food’ but represents a most sophisticated signalling system of mammalian evolution promoting a regulatory network for species-specific controlled m-TORC1 driven postnatal growth and metabolic programming. Milk signalling is mediated by milk-derived BCAAs, which stimulate the secretion of insulin and IGF-1. Exaggerated m-TORC-1 signalling induced by formula feeding appears to represent the underlying mechanism explaining exaggerated postnatal growth, aberrant adipogenic, hypothalamic and allergenic programming, laying the foundation for the development of the chronic diseases of civilisation, i.e., obesity, type 2 diabetes, dyslipoproteinaemia, arterial hypertension, allergic and autoimmune diseases.” (cited on p.141 of Milk Matters). Read the whole section that explains all this. Or the online article Melnik BC, John SM, Schmitz G. Milk is not just food but most likely a genetic transfection system activating mTORC1 signaling for postnatal growth. >https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-12-103″

All three streams of evidence are to some degree discussed and referenced in my book, Milk Matters. It takes a book and years of work to catalogue this expanding field.

Also covered in that book, and much less often discussed, is what I see as a fourth neglected stream of vital evidence: the experience of the infant formula experiment itself – or to be accurate, the unending stream of experimental infant formulas. Formula may mean the absence of breastmilk’s benefits, but it is a presence as well. The constant stream of changes to infant formula declared as perfect, and always “as close as possible to breastmilk”, act as evidence of the risk of substitutes. Improving on that declared perfection is in reality trying to correct newly identified imperfections – deficiencies, excesses, contaminants, unpredicted interactions.

For example, the only era in which almost all formula-fed-infant brains got absolutely no important omega-3 fatty acids was from roughly the 1960s to 1990-2001. This was the era of the new, perfect, ‘modern formulas’ that replaced home-made evaporated milk mixes, and dried milk powders which took out milk fat and used coconut, peanut and palm oils, and banned the traditional use of fish oil or vitamin A drops (after harm from vitamin A excess in formula fed infants). The era’s obvious increase in brain disorders has not been researched in relation to this change – even though we now think omega 3 fatty acids and milk fat derivatives are important for normal brain development. Industry recognised this earlier than health professionals, and experimented with egg lipids and fish oils before Martek genetically engineered marine algae and soil fungi to produce these fats on a commercial scale, and made billions doing so. (No one has assessed the effects of peanut oil and egg lipids in some brands of formula. In the 1980s it was naively believed that “oils can’t sensitise”.)

Much of what is known about the performance of infant formulas is closely held by companies in competition with one another for the lucrative infant formula market.

More people die as a result of infant feeding in disadvantaged communities, yes. As a species, that is probably a Good Thing, though obviously is is a tragedy and waste of human potential. Only healthy survivors with strong immune systems get to reproduce. Logic and health data says that more people survive in advantaged communities, and will reproduce a next generation more prone to vertically communicated diseases such as heart disease, diabetes and obesity. Does the effect compound or snowball?

Why do I think that grandchildren are affected? Postnatal nutrition affects infant and development; childhood growth and development affects adult health; reproducing (males and female) adults’ health and immune systems affect the next generation they together create and gestate. Awareness of the intergenerational and transgenerational effects of infant feeding, and the many powerful properties of mammalian milk, has only just begun. It can be proved beyond doubt in other mammals, though still debated in humans (largely because the experiments that establish the facts in mice simply cannot be done in humans.) If you doubt that, read, Milk: the Biology of Lactation, by two researchers at the American College of Obstetricians and Gynecologists, one a Smithsonian scientist and the other a faculty member in the Department of Neuroscience at Georgetown University. (And read my review of that book, shared with its authors, at https://infantfeedingmatters.com/milk-the-biology-of-lactation/ )

As the authors of that earlier quote went on to say, “It has only been in the last few hundred years that a brief interlude of human arrogance questioned the primary importance of breast milk and suggested that humans could devise something better. That unfortunate episode of history perhaps can be encapsulated by two famous lines from Alexander Pope’s 1709 Essay on Criticism: “A little learning is a dangerous thing” and “Fools rush in where angels fear to tread.” (Power ML, Schulkin J. Milk: the Biology of Lactation, page 233).