LEAPing to conclusions: when to introduce foods

LEAPing to conclusions about timing of widening the diet.


Any society’s most common food allergens reflect both the immunological characteristics of the foods, and the cultural use of those foods. The most common western allergens are cows’ milk, egg, peanuts, and wheat, with cows’ milk protein allergy/hypersensitivity negatively affecting (and indeed killing) more children than either egg or peanut allergy.

Corn and soy allergy have long been common in a country like the United States where these cheap taxpayer-subsidised foods are over-utilised in the diet; corn and soy have since become global allergens following the use of these staples in infant formulas. Egg and peanut have also featured in industrial infant formulas over the decades since the 1920s, when brand name industrial products began to proliferate and replace simpler cows’ milk mixtures.

Cereals are typically talked of as first foods, but the first foods directly introduced to most babies are in fact whatever foods are contained in a particular infant formula: cows’ milk, soy, corn, sometimes egg, seed/fungal/algal oils, starches and oligosaccharides from wheat, rice, potato, emulsifiers and much more.[1]

Early formula exposure and its effects

Perinatal exposure of breastfed infants to such infant formulas has long been a feature of western hospital practices. This is a critical first assault on the natural immune defences provided by both innate and adaptive mechanisms. One lawyer has advised that without fully informed consent, it could legally be considered battery. Long-lasting effects on the infant gut microbiome have been documented for over a hundred years. For example, 1970s work on the gut effects of early formula supplements was summarised by Bullen as “Breastfed infants who receive supplements behave as bottle-fed babies…”.[2] As he went on to say, It is important to emphasize that when supplements were fed during the first seven days of life the production of a strongly acidic environment was delayed and its full potential was never reached.”

It is not just pH, but also the gut microbiome, that matters. Where are similar comparative studies, by brand, of the gut effects of substances fed as supplements to breastfed infants? Given recent awareness of the importance of gut eubiosis to the development of tolerance, and as Professor Allan Walker put it, the “necessity of breastmilk as the first source of nutrition”[3], I find it astonishing that most studies evaluating the infant food allergy issue still fail to control for peripartum exposure to infant formula and so-called fortifiers. Yet most allergists would see antibotics and stress and antacids as extremely relevant because of their effects on the microbiome. Those helping breastfeeding women know that cows’ milk exposure is equally relevant. In my work with mothers to ensure exclusive breastfeeding in the subsequent children of allergic families, parents have noticed a huge difference in exclusively breastfed children compared with their supplemented siblings.

Allergists rarely if ever deal with truly exclusively breastfed babies, or attempt to discover early feeding history in detail. When they do, the results make certain connections obvious. A longitudinal prospective cohort study in Denmark[4] followed 1749 children for the first year of their life. At 12 months 39 met strict criteria for a diagnosis of cows’ milk allergy, 22 after weaning to formula. 17 developed symptoms of CMA while still breastfeeding, all under the age of three months[5]; 8 of these were predominantly formula-fed when symptoms emerged. Only 9 were exclusively breastfed at the time of diagnosis; all nine became symptom-free with maternal dietary elimination of cows’ milk protein. Six of these nine developed symptoms between 2 and 4 weeks, to me indicative of perinatal exposures. Checking nursery records revealed that all nine had been exposed to infant formula perinatally, although only one of the nine mothers was aware of that fact. The cumulative rate of 2.2% overall was in a population where 21% were solely breastfed at 6 months, the age at which introduction of most solid foods was recommended. (12 months was the recommended age for egg, fish, tomato, strawberries, chocolate, nuts, berries, legumes.) Denmark in 1985-1986 was recording findings very similar to the experience of the Australian mothers I dealt with in that time period: if a baby was symptomatic when solely breastfed, perinatal cows’ milk exposure was certain; and maternal diet changes ended symptoms (though not sensitivities lifelong.)

Ignorance about exclusive breastfeeding

It is obvious from the literature, and from mothers’ experiences, that any potential negative impacts of early alien food given to breastfed infants are a long way from the minds of hospital-based allergists. And this neglect remains a critical missing factor in allergy research,[6] just as it was in research about health outcomes in developed nations until Peter Howie’s groundbreaking study, undertaken only after he had been challenged to prove what he once asserted, that truly exclusive breastfeeding would make no difference in any country with clean water supplies.[7] Allergists need to be similarly challenged. It would be helpful if we had many more studies which took this much care to record infant feeding: a meta-analysis might then be of some use. Even systematic reviews are worthless for lack of such care.

In the UK EAT [Enquiring About Tolerance] study, for example, simple maternal report of “exclusive breastfeeding” was the condition for enrolment of 3 month old babies from the general UK population, but there was no public discussion of how to verify total avoidance of early formula “top-ups” or fortifier use in hospital, and no faecal sample was taken until three months. Typically in the UK, many of these perhaps-solely-breastfed-at-three-months infants would have been supplemented prior to three months of age, unless parents had made strenuous efforts to avoid such contact due to concerns about allergy (which itself would introduce bias into the study.) Skin-prick testing was done to identify the already-allergic only in the early introduction arm (foods at 3 months). There was no such identification of existing allergy for those in the standard arm, who were “encouraged to breastfeed exclusively to 6 months”[8] regardless of past or present reactivity status – the EAT protocol[9] in fact made it clear that study authors expected mothers to introduce formula before six months, although this is not later discussed.

The impact of either in utero or early postnatal sensitisation will thus not be identified among those who were encouraged to breastfeed exclusively to six months and then introduce ‘other’ foods, amongst which formula is often not included. Yet intra-uterine sensitisation is well documented, and those first prenatal and perinatal food exposures are potentially the most damaging, programming the child for a lifetime of immune distortion via gut dysbiosis. If the families I have dealt with are typical, intra-uterine sensitisation is more common where mothers themselves had been poorly breastfed or formula fed from birth. Such intergenerational concerns are not addressed in EAT, for example, despite the new science of epigenetics making it clear that these are significant.

So only rarely are prenatal and perinatal exposures part of the discussion about the age at which foods other than breastmilk are introduced into the infant diet. Yet those exposures and sensitisations can determine the breastfed infant’s responses to the introduction of foods, affecting compliance with complex regimes of food introduction such as EAT proposes. It is a rare breastfeeding mother who ignores her child’s aversions and emerging symptoms, and persists with force feeding of foods the child dislikes. This no doubt explains some of the common failure to comply with assigned food introduction regimes, so that intention to treat analyses show little or no significant differences between groups, although compliance analyses may.

Media reports and research realities

At present we are seeing a spate of media reports claiming – often ahead of publication of the trial protocol and data – that to introduce other foods “early” introduction of foods may prevent the development of allergy. In popular understanding of the debate about when to introduce foods other than breastmilk, “early” is under six months of age, or around 4 months, which has assumed an unwarranted status as the “traditional” age. “Late” in popular understanding means after six months, as the World Health Organisation recommends. To date most industry propaganda, such as the INFORM document disseminated to UK health professionals, argues strongly to retain 4 months, the age at which it is thought in utero body stores of essential nutrients may be exhausted. But four and six months are not the definitions of early and late in almost every study now being cited. While I need to analyse each report separately (and will over time) there is one particularly glaring example: the LEAP Trial.

This trial[10] looked at prevention of severe peanut allergy among high-risk Jewish children in both the UK and Israel, and emphasizes household dust and skin exposure, suggesting that foods contacted via infant skin, but not ingested early in life, may be less well tolerated. Omitting maternal pregnancy and especially lactation diet as potential sources of infant exposure seems therefore a wee bit problematic.

That aside, LEAP has been widely misquoted in the media and by health professionals as justification for widening the diet of every breastfed infant under 6 months. Why is that use of this study completely inappropriate?

For a start, its inclusion criteria were children between 4 and 11 months who already had been “successfully introduced” to foods other than milk, so ‘successfully’ that they had developed either egg allergy or severe eczema. These were children at high risk of severe allergy, somewhat arbitrarily considered to have been sensitised by skin exposure to antigen in household dust.[11] Alternative sensitisation routes such as exposure to peanut oil in formula, or to peanuts in utero, or via an allergic mother’s milk, were not investigated. Participants were skin-prick tested for peanut allergy before they were accepted into the trial, and some 10% of children were rejected if the skin wheal size was too large.

But here’s the critical fact. The median age for this initial screening to enter the trial was 7.8 months. That establishes conclusively that the majority of the children were not under 6 months old. These screened, not-hugely-peanut-reactive, not exclusively breastfed, children were then randomised to eat or not eat peanut; those eating were required to consume at least 2g peanut three times a week until they were 60 months old. They were then tested at age 5, and outcomes sorted by either early – before 11 months – or later – after 11 months – peanut exposure and adherence to trial protocol. (There were many dropouts, as one would expect over five years.) If children accepted the regime that their parents were able religiously to administer, peanut allergy rates at the age of 5 years were significantly lower than among those children of parents randomised not to give peanuts in the first year. Which means that this preventive strategy could work well for all allergic children who will not refuse study foods, possibly because they can tolerate them! Breastfeeding mothers report very young children disliking the smell of, and absolutely refusing to eat, foods to which they later are proved hypersensitive. A detailed analysis (of the early infant feeding history and milk and faecal microbiomes) of dropouts -some 42% – in the exposure group might be interesting.

To recap: EARLY exposure was defined as between 4 and 11 months; LATE exposure was after 11 months. And yes, there was a major outcome difference. Children who followed the quite recent (1990s-2000) medical advice to avoid peanuts for the first 12 months were more likely to be severely allergic to peanuts at five years of age than those who were regularly exposed under 11 months of age (as 1970s children had routinely been: peanut butter was once a staple weaning food.[12]) But for most of these Jewish children, “early” was in fact within the WHO recommended period of around or after 6 months for exclusively breastfed children. Not that any of these children were in fact exclusively breastfed: remember, all had been “successfully introduced to other foods” as a condition of trial entry, and were already reacting to egg or had eczema. Maternal peanut intake and thus exposure to peanut via pregnancy and breastmilk was also not recorded or discussed, nor was the composition of any infant formulae discussed.

So what is early and what late exposure?

LEAP showed that it’s best for already allergic babies to be introduced to other foods before 11 months of age, and while continuing to breastfeed, to go on eating those foods consistently, if they do not react too badly to the process (as some did). Probably no one in the infant feeding world disagrees with that (other than a few stubborn hypersensitive infants). WHO wants children to be eating other foods after 6 months, not after 11 months.

Yet EARLY introduction of foods is now being assumed by many to be before six months; LATE is being assumed to be after six months. Why? I can find no details in this study of just how many breastfed- versus artificially fed- children already eating solids between 4-5, 5-6, and 6-11 months, reacted when fed peanut or not fed peanut for five years, compared with those fed it after 11 months. And, as noted repeatedly, there were no exclusively breastfed children in the study. I can therefore see no relevance of this study to the debate about when to widen the diet of exclusively breastfed infants, at 4 or 6 months. What applies to the exclusively breastfed does not apply to mixed fed or formula fed infants, of course, as both have had a myriad of other food sources introduced via the infant formula they consume, best understood as a veritable soup[13] of processed ingredients.

Can we LEAP into practice?

So why on earth would anyone quote LEAP as justification for ignoring WHO’s recommendation for true exclusive breastfeeding from birth to around 6 months, a recommendation based on good science, basic physiology, common sense, and global experience? The LEAP study actually supports WHO, when the majority of children who went on to be tolerant were given foods between six and 11 months. And LEAP also makes it clear that some babies must avoid some foods or have serious reactions, as parents know. LEAP excluded the worst reactors by skin prick testing, after all.

How can LEAP, with its individual skin-prick testing, translate into general practice if the guideline is changed to 4 months? And if it is impractical, why is it being discussed as though early introduction can be safely implemented? The EAT authors said in their protocol, “..we believe there is no value in trying to achieve a modification of behaviour to such a degree of compliance that it could not be expected to be achieved as a public health measure. In other words there is no point trying to ensure a regimen of complete avoidance [of formula in the so-called exclusively breastfed to 6 months group] if this cannot be realistically carried out in real life outside of the setting of a study intervention.”[14] And there is no point trying to get already sensitised children to eat foods that make them ill, or parents to feed them those foods, outside a study setting either.[15]

What does the controversy mean for mothers and babies?

WHO’s population guideline is six months exclusive breastfeeding for all children, with breastfeeding then continuing into the second year or longer, during the first years that the healthy human microbiome is becoming established. WHO explicitly allows for clinical variation on an individual basis, recognising that some babies are physiologically ready before, and some after, six months, and that some mothers find it difficult to provide enough milk. Yet media releases by different doctors and allergy groups (and of course industry sources) first misrepresent WHO’s position at being exactly 6 months, and then say this rigid guideline should change. The result: the reality some mothers are having to deal with. Read what follows…reproduced with permission from a Facebook post:

“I had my allergist appointment yesterday, and I’m so upset and confused. They wouldn’t do the prick test because she said Katie would react to everything because of her eczema.[which had been severe before and hugely improved after maternal dietary milk elimination: MM.] So they want me to start her on food, including giving a boiled egg yolk first, then egg white; also to do crushed up peanuts on the inside of her lip. She is only 4 months. This is not sitting well with me at all.  They said it’s a new thing they are doing now to desensitize the body to the foods. Since I have been off dairy there has been a huge improvement with her, but she is still reacting to something. I told the allergist this, and that her poo is still green and runny and she is always still throwing up. She said the more foods you eliminate, the more problems you cause. [The allergist didn’t hear the bit about how things had improved, obviously.] She also said just give a whole variety of foods at once, and when I said “shouldn’t it be one food for 3 days so I know what she is reacting to”, she said “yes you’re right”. I just don’t know what to do, as I’m not going to know what she is actually reacting to.”

How dangerous such advice is, when a rural mother is sent home from a major children’s hospital, without medical backup, to give peanuts and egg to a child once almost covered in disfiguring eczema, whose gut is still not fully healed. The LEAP study did not and does not support such practice. But it is being cited in a major Australian allergy clinic as doing so. This breastfeeding mother went on to eliminate one more food, soy, and her child’s eczema improved again. However hard any mother finds dietary restrictions, she prefers them to a miserable baby or giving up breastfeeding, the one thing that gives her some peace and comforts her child!

Research is ongoing, but to date I have seen nothing but assertions about the preventive value of four rather than six months for the fully breastfed infant. I absolutely agree that the AAP in 1980 got it right for the formula-fed infant: four months is indeed the time to end total reliance on any single dehydrated industrially-processed product, since by four months, in utero nutrient stores are exhausted. There have been many problems as a result of defective infant formulas[16] and all are associated with ongoing metabolic disorders, from differences in brain white matter and reproductive tissue development to obesity. No wonder the $50billion formula industry generally supports 4 months as the age to widen the diet. I am unaware of independent studies of outcomes in infants exclusively fed formula for 6 months: as Professor Alan Lucas has pointed out, even small differences between formulas can have significant effects. And EFSA notes that “There are numerous publications which discuss the timing of initiating complementary feeding with regard to breast-fed infants whilst the literature on non-breast-fed infants is limited”[17] Should weaning begin earlier, and emphasize different foods, for the artificially fed, given the links with adult obesity? Where are the studies? And why is there so much focus on the exclusively breastfed, the smallest and least-at-risk group of western infants?

What I can’t see is why anyone without any vested interest would cite the LEAP study (or any study without an arm of truly exclusively breastfed children in it) as having any relevance to the debate about whether to widen the diet of exclusively breastfed infants before 6 months of age. Let’s do the studies on truly exclusively breastfed children before making any more unjustified guidelines about adding in foods of lesser nutritional and immunological value to their diet under 6 months of age. (Some of those foods even reduce the value of breastmilk: pears, for example, chelate iron, making it less bioavailable.)

Problems of universal guidelines that disrespect breastfeeding

For guidelines have many consequences, even where mothers don’t know or adhere to them. In suggesting widening the diet at 4 months rather than after 6 months, health professionals seem not to have taken into consideration the realities of modern infant life. Allergy is not the only health concern for the infant. If infants under six months are not exclusively breastfed, infection rates will rise, and antibiotic exposure and resistance increase. Even without the stress of infections, multiple polyvalent vaccinations (and sometimes a day or more recovering from them) punctuate infant experience under 6 months. While immensely valuable, vaccination does stress the infant body and require nutrients to be deployed in response. Combining exposure to new and potent food antigens and vaccinations seems unlikely to be a good idea: I was told decades ago by Professor RRA Coombs that such combinations induce allergy in laboratory animals. So why would anyone introduce other foods unnecessarily at 4 months? Why hasten the change from the optimal non-inflammatory infant gut microbiome created by breastmilk? Certainly the previous advice not to give children peanut under 12 or 24 months was a mistake, but exposure from three to four months may also be a mistake, compared with around/after 6 months, which basic science suggests is about right. Will allergists get it wrong again? What’s the rush to decide before we have relevant studies?

Then there is that largely ignored problem of already sensitised children, and maternal diet. Human milk immunobiology is rarely mentioned by allergists, though milk is the primary mammalian immune strategy for protecting newborns. Depictions of organs of the immune system fail to include the breast, although the thymus – shrunken by formula feeding – is always pictured.[18] Yet breastmilk continuously exposes infants to all the foods a mother eats, along with all other environmental inputs, in manageable doses, educating the immune system of the child, and supporting it by many bioactive and immune factors including a vast microbiomic array and immune repertoire. Why not study maternal diet and milk and the milk microbiome? Was the old 1940s medical advice for breastfeeding mothers to eat peanuts to boost their milk supply a cause of the increase in peanut allergy, or did it prevent it? Should we be concerned that industry is marketing to mothers (before, during and after pregnancy) the microbes in its formulas, probably ensuring that the breastfed baby’s microbiome becomes more and more like that of the formula fed? The use of bacteria marketed as “probiotics” is becoming very widespread despite the absence of studies assessing its impacts. Commerce is way ahead of science, and no one is monitoring the results.

What of the already allergic?

If the mother is herself allergic, it is clear that the results of allergen exposure via breastmilk can be different for the child than if the mother tolerates the foods. This may be due to epigenetic changes created by previous generations’ feeding practices: mothers who gestate babies were themselves affected by how they were fed. In formula-affected communities and generations, high rates of food hypersensitivity among mothers are now usual, and so it is likely that many infants are sensitised in utero, and many clearly react to allergens in breastmilk.[19] There is increasing evidence that babies that become allergic are immunologically different at birth:

“Now, Zhang et al. report that infants who later developed food allergy had altered immunity at birth. Cord blood from these infants had more monocytes compared with CD4+ T cells and decreased numbers of regulatory T cells. Moreover, the monocytes from food-allergic infants secreted more inflammatory cytokines than those from healthy infants. These cytokines suppressed interleukin-2 (IL-2) expression by CD4+ T cells and skewed differentiation of these cells to a nonclassical T helper 2 (TH2) phenotype.”[20]

Discovery of the mechanism by which this occurs may eventually be useful; proof that this happens during pregnancy is helpful. But this is not new to anyone who has been reading my work since 1980, and my books since Food for Thought in 1982. What happens in pregnancy, including food allergen exposure, affects what happens after. So what has affected your mother affects you. So the intergenerational effects of infant feeding are involved in making the next generation allergic. I and innumerable breastfeeding parents have been saying so since the 1980s. To me, this is further proof of my Milk Hypothesis, since infant nutrition is indeed, as key researchers have said, “the single most important postnatal influence on lifelong development.”[21]

The previous writers went on to say “Anti-inflammatory strategies should therefore be considered in preventing food allergy in these individuals.” What strategies? Read Milk Matters: infant feeding and immune disorder[22]  Then think about the choice of foods for babies: breastmilk with its huge range and variety of anti-inflammatory and repair factors, and formula, with its huge range of pro-inflammatory factors, from the advanced glycation end products produced by heat to the alien proteins and fats, to the unnatural industrially-made carbohydrates, the additives with traces of extracting chemicals…… and its absence of those modulating factors in breastmilk. What choice would any intelligent parent make if they possibly could? Should parents of very young infants have to make a choice between normal food and industrial substitutes, or should they ALL be enabled to breastfeed by changes in societal structures and attitudes, with breastmilk available for mothers who genuinely can’t provide enough milk? Should mothers providing anti-inflammatory food for infants  be rewarded for so doing?

ALL babies not breastfed are being exposed to pro-inflammatory pressures that result in – guess what – the range of western epidemics with their roots in inflammation, from CVD to auto-immune disease. SOME of those babies are lucky in their genetic inheritance and escape those consequences, though their children probably won’t, as they gestate the next generation, and as these researchers are discovering, immune changes happen in utero.. But ALL babies not breastfed are at needless risk. And ALL formula-feeding mothers and babies miss out on normal female/mammalian experience which can make both mothering and  thriving pleasurable.

Should we give all allergic mothers the same advice to eat everything, including foods she and her baby both react to? Is that an anti-inflammatory strategy? Not likely, methinks. Why would we give her such advice, when avoidance can mean both mother and child rapidly lose unpleasant symptoms? No mother will go on causing her baby pain and herself distress if a change of diet leads to symptoms improving or disappearing. She will simply lose trust in those who advise her to.

What strategies are safe?

The latest EAT publication says, “Further analysis suggests that the possibility of preventing food allergy by means of the early introduction of multiple allergenic foods in normal breast-fed infants may depend on adherence and dose.”[23] Ideally perhaps, low but consistent exposures while breastfeeding might build tolerance. But perhaps EAT researchers need to realise that tolerance may depend on the vehicle of introduction, the breast, as well as the maternal and child dose. The many immunoregulatory and healing properties of breastmilk are rarely considered, and the basic science of breastmilk immunology is in its infancy. The discovery of pluripotent stem cells is less than a decade old. Feeding “into the second year and beyond” as WHO advises leaves plenty of time for exposure, both via milk and in other forms while still breastfeeding. No mother needs to end breastfeeding at 6 months, as official allergy body advice sometimes implies is, or accepts as, inevitable. The one thing allergists seem to agree on is that introducing new foods while breastfeeding continues is more likely to create tolerance: so why don’t they actively promote WHO’s policy of years, not months, of breastfeeding? (Blinded by western industry-led assumptions of what is possible and normal?) It is true that in the EAT study, continued breastfeeding was shown to be equally likely (or unlikely) in both groups, but then these were mothers being actively encouraged to continue breastfeeding for the purpose of the study: in the real world few mothers have teams of dietitians validating their breastfeeding as important to their child’s health. And many hospital allergy clinics routinely advise weaning from the breast, as online groups of allergy sufferers testify.

Clinics also routinely skin-prick test infants over 6 months of age. If LEAP is right and the skin is a potent route for sensitisation, perhaps such testing itself is a risk, the consequences of which emerge only on later exposure. Has research established conclusively that skin prick tests cannot sensitise the exquisitely sensitive infant immune system? Some mothers report that clinic testing leaves their children worse than ever. Already sensitised children who reacted with major skin wheals when skin-prick tested were excluded from the LEAP study. This was because any already-sensitised child, if exposed (early or late) might well suffer anaphylaxis. That in turn implies that, before the diet is widened, those at high risk of allergy need to be identified in ways unlikely to increase their risk of severe reaction. What healthcare system could support universal skinprick testing?

At birth, cord blood total IgE was reported in the 1990s to be strongly predictive of subsequent allergy; and a well-administered questionnaire can identify parental and sibling atopy. This is true even when the initial response to a question about family history of allergy is negative (due to parental ignorance of the diverse forms allergy can take). But again, who will do this work on a population scale, whether to advise those at risk to continue exclusive breastfeeding, or the mother about adding or removing dietary allergens? Or the timing and duration and frequency of such changes? Some babies in fact thrive best on longer exclusive breastfeeding than WHO would recommend as a universal guideline for the breastfed; so it is important to remember that in the past, 9-12 months was universally advised as the time to transition children to family diet, with 6-9 months seen merely as a period of ‘educational diet”, that is, a time of exposure to a wide variety of tastes, without many calories.

Consequences for breastfeeding families of too-early food introduction

Concerned parents really should not be bullied into giving breastmilk-displacing foods under 6 months without knowing their child’s relative risk or reaction. Nor should any parent be bullied into ignoring a child’s strongly negative responses to dietary inputs, or symptoms produced by such exposures. Many a child develops serious eczema only after patches of dry skin and cradle cap have been dismissed as insignificant responses unrelated to foods, by those less experienced in caring for breastfeeding families. This all makes early identification and regular growth monitoring of allergic children a necessity, in my view. I have seen startling changes in growth velocity when allergens were removed from children’s diets, so that nutrients being used for immune defence became available for growth. Those who work with allergic breastfeeding mothers with “minor’ symptoms can sometimes prevent the major symptoms from developing, or at least delay their emergence. (And it is a huge benefit even to delay the emergence of allergy. It is much easier to adjust to parenthood when your baby is happy and thriving, than when she is miserable and disfigured by eczema, or crying incessantly with gut pain.)

But allergy is not all there is to life and diet. There are many other consequences to widening the diet of any child. Doing so takes time, makes mess, and re-structures the day for the family. For the breastfeeding mother, the period from 3 months on has been called the reward period, as initial supply problems settle and babies become delightfully responsive and interactive. This is when a first-time mother can relax, confident that she can feed and protect her baby, and she can take that baby everywhere with a minimum of equipment and forethought. When there is no need for nutrients other than those breastmilk provides – and that has been proved true for most babies– why add the work of introducing and cleaning up after other foods needing to be processed into a semi-liquid or paste a young infant can swallow without choking? Or the expense of buying ready-to-feed gloops? Why hasten the day of revolting excreta? Or the work of remembering religiously to provide certain doses of specific foods each week, documenting them to be sure not to forget? (The EAT study requires that at 5 months a mother must reliably provide and get the child to eat doses of seven different allergens at least twice a week: what a hassle!) Let’s not forget on whom all that extra work will fall.

Breastfeeding provides much more than food. No other food is as bioavailable and biologically active as human milk for the first 6 months of life (and even beyond that age for some); no other method of feeding is as simple and emotionally/hormonally rewarding for the mother, or as protective lifelong. Everyone who advises curtailing breastfeeding or supplementing early is increasing the maternal workload, and also increasing both maternal and infant health risks life long, as well as the maternal need for contraception and maternal stress levels. They may also increase the risk of postpartum depression and damaged relationships between parents and child: a miserable baby is hard to love, and constant crying can lead to abuse. Why shorten the period of easy baby-feeding, the normal period of lactational amenorrhea that allows mothers’ bodies to recover from pregnancy and birth with its blood losses? Token continued breastfeeding is not as protective for the mother as full breastfeeding, with its suppression of ovulation and reduction of stress hormones. Rates of reproductive cancers will rise if periods of exclusive breastfeeding are reduced. Women’s health matters as much as their children’s. Yet the huge collateral damage of introducing other foods any earlier than necessary is rarely mentioned by allergists. Tunnel vision is a serious occupational hazard for researchers.

Maternal dietary manipulation or formula fix?

Milk provides much more than nutrients. The reality of different immune factors in breastmilk should be emphasized to mothers, both to encourage them to continue breastfeeding, and to provide potential no-fault explanations for any problems. This needs to be done with a strong emphasis on the superiority of any breastmilk to any formula. Instead, the possibility that some breastmilk might not have an ideal immune profile is likely to be used by industry (and formula fantasists) to discourage allergic mothers from breastfeeding, and to increase sales of specialised formulas.

These claim to be better than more-allergenic regular formulas, and some women believe them to be superior to their milk (believing still that breast is best, just not their breast.) There was little independent research before the so-called hypo-allergenics were introduced, and even the most extensively-hydrolysed formulas claim to reduce symptoms in only 90% of patients. Yet gullible health professionals already advise the use of such formulas as treatment before trying support of breastfeeding with maternal diet changes – even though with formula there is no proof of benefit, a wide range of potential risks, and a huge increase in costs to taxpayers or parents. For over-busy professionals, a formula can seem the easy solution to time-consuming allergy problems – but it rarely is for breastfed babies and mothers.

Mothers have learned that, while initially difficult, avoidance of their own food allergens can have dramatic effects on their breastfed baby’s behaviour and health, and their own. Yet their experience is often ignored or contradicted by those who know less about the child, the mother, breastmilk, breastfeeding, or the diet, or who patronisingly decide that for the mother giving formula is less difficult than diet changes.

Conclusions that seem logical to me

Personally, I can’t see how it can ever be possible for health authorities to have one single recommendation for artificially-fed and breastfed infants alike, and for atopic and non-atopic infants alike, when both the risks and the children are so very different. So why not work on separate guidelines? They might be

  1. Exclusive breastfeeding to around six months with advice about maternal diet, and continued breastfeeding into the second year and beyond, with:
  • inclusion of all foods mothers tolerate without problems; OR
  • initial exclusion of foods that cause symptoms in the mother, followed by careful reintroduction over time while breastfeeding continues, ideally into the second year of dangerous toddlerhood and exposure to daycare.
  1. Partial breastfeeding or formula feeding exclusively only to 4 months at most, with inclusion of other foods and widening of the diet from then on, including all major allergens unless the child has already developed sensitivities, in which case careful graded re-introduction under supervision. These children are at greater risk of overall ill-health, particularly those entirely formula-fed from birth.[24]

Why has there not been universal support for the “around 6 months” approach (which fits all the physiological markers of readiness for other foods), along with clinical awareness of the already sensitised child, and advice to support mothers with diet modifications that prolong breastfeeding, allow gut healing and increase the chances of tolerance as the child’s immune system matures postnatally? Yes, mothers need to eat well. But they do not need to eat large quantities of all the common allergens to eat well. Nor do their children. Any breastfeeding is good, and allergists – like WHO, and unlike their industry sponsors – should encourage it well past six months. But successful exclusive breastfeeding in the first months of life is significantly better than mixed feeding, or minimal breastfeeding, from many points of view, including that of the microbiologist and the mother.

It is ignorance of these basic biological facts about formula and breastmilk which allows the “start solids at 4 months” push to continue, before there is incontrovertible evidence to support it. How can we explain its persistent global strength? To answer that question requires detailed knowledge of the history of the 4 months prescription, along with an awareness of the massive industry interest in, and influence on, this research. A lot of money is at stake, and liability for harms yet to be sheeted home. This whole debate has been framed by industry, and by the assumption that formula and breastmilk aren’t all that different, so that important issues such as what needs to be done about mixed-fed and formula fed infants are simply ignored. The truly exclusively breastfed child is not only the least of our worries, but also the rarest of creatures. This and many related issues are discussed at considerable length in my latest book, Milk matters: infant feeding and immune disorder. One relevant chapter giving the background can be read online at https://infantfeedingmatters.com/2015/10/24/four-months-or-six-or-neither-when-to-widen-the-milk-diet/

But I want to conclude this piece with the voice of a mother being damaged by this stupid controversy. I get many such messages; this one is the most recent.

“I’m a breastfeeding mum and my eldest has food allergies. I’ve stumbled across your research and I’m very keen to read lots more and get my hands on your book (Milk matters: infant feeding and immune disorder). I’ve listened to your presentation (www.ilactation.com/present) and I cried, because it was one of the only things I’ve come across in 2 years that makes so much sense and doesn’t fill me with the guilt I’ve experienced for the last 2.5 years. I was a formula fed baby from the day I was born. I thrived. I’m smart and I didn’t get sick a lot as a child. I have no allergies. When I had my first bub I was determined to breastfeed. My parents were supportive. 2 days after my daughter was born staff at the hospital convinced me he blood sugar was low and kept heel-pricking her to check it. I ended up agreeing and signing a form to give permission to give her a single bottle of formula. It was the only bottle of formula she ever had as the next day an amazing IBCLC walked through the door and gave me the confidence I needed to continue. My daughter had her first allergic reaction to yogurt at 6 months old. She also developed egg and nut allergies. She’s already outgrown cows’ milk allergy and is currently outgrowing egg. I now have a 4 month old. She’s only ever had breastmilk. The allergists are encouraging us to introduce solids between 4-6 months when bub is developmentally ready. I’m conflicted as I’ve been told by many medical professionals (not our allergist) that if I’d fed my eldest daughter solids earlier she wouldn’t have allergies, and on the other side I’ve heard that feeding early will also cause allergies. I’ve been in tears over it since she’s turned 4 months. I don’t know what to do.”

What are these health professionals saying about the mother’sbreastmilk? And why are they ignoring that needless initial hospital exposure and its consequences for the child of a mother herself formula-fed as an infant?

Maureen Minchin 2016

[1] The use of wheat (both in infant formulas and as a first cereal for infants) has not been thoroughly evaluated for its contribution to western epidemics of gluten intolerance. Wheat has simply been replaced by rice, so perhaps rice allergy will increase in non-Asian countries as a result (Japan’s most common allergens were once reported as fish and rice.

[2] Bullen CL. Infant feeding and the faecal flora. Chapter in Wilkinson AW (ed). The Immunology of Infant Feeding (Plenum Press 1981) pp. 41-52

[3] Walker WA, Shuba Iyengar R. Breastmilk, Microbiota and Intestinal Immune Homeostasis. (PMID:25310762) Pediatr Res 2014. DOI:1 0.1038/pr.2014.160.

[4] Host A, Husby S, Osterballe O. A prospective study of cows’ milk allergy in exclusively breastfed infants. Acta Paediatr Scand 1988; 77:603-670.

[5] At 3 months 52% of the cohort of 1749 were solely breastfeeding. 2.2% of this would be approximately 20

[6] Since 2011 I have repeatedly asked certain researchers for the results of an outcome comparison between two groups of roughly 90 infants, those solely breastfed from birth, and those solely formula fed from birth, within a much larger study which found few effects of complements when comparing mixed fed groups. Resources to analyse this excluded data have not been available in this industry funded study. Make of that what you will; I find it very strange.

[7]See Minchin M. Milk matters: infant feeding and immune disorder (2016) pp.434-435

[8] In the UK, perhaps 1% of children are able to do this. Intention to breastfeed to 6 months may be a meaningless category in this study group, unless resources are provided to enable rather than encourage, a group that doubtless will include women hoping to prevent allergy by following WHO advice. See https://www.eatstudy.co.uk/eat-study-info/

[9] https://www.nejm.org/doi/suppl/10.1056/NEJMoa1514210/suppl_file/nejmoa1514210_protocol.pdf

[10] Du Toit G , Roberts G , Sayre PH , Bahnson HT et al. Randomized trial of peanut consumption in infants at risk for peanut allergy.N Engl J Med 2015; 372(9):803-813.

[11] The evidence about the ubiquity of peanut allergens in household dust has led to the interesting hypothesis that sensitisation via skin occurs when foods are contacted but are not being consumed. But maternal consumption of any food will mean exposure via breastmilk, and inclusion of foods in formula or vaccinations means micro-exposure via those means; these possibilities are not adequately discussed in the study or by its commentators. (Yes, peanut oil has been used in vaccinations.)

[12] This did prevent childhood anaphylactic reactions, but not necessarily sensitisation: one milk-allergic child not diagnosed until after four years of age was apparently tolerant of peanut butter during weaning and childhood – but as an adult reacts with an instant headache if the lid is left off an unseen jar of peanut butter.

[13] Milk Matters, p. 203

[14] https://www.nejm.org/doi/suppl/10.1056/NEJMoa1514210/suppl_file/nejmoa1514210_protocol.pdf

[15] We could more easily get babies exclusively breastfed to 6 months if researchers did not consider that a pointless exercise.

[16] This was the ultimate trigger for the AAP’s acceptance of 4 months according to Prof Lewis Barness in 1981. For breastfed infants there seems no advantage and some disadvantage to early supplements. When one uses an artificial formula, no matter how good, one must beware of possible missing ingredients. Weighing advantages and disadvantages, the Committee…felt that 4 to 6 months of age was reasonable with present evidence.’ Pediatrics 1981

[17] EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA): Scientific Opinion on the appropriate age for introduction of complementary feeding of infants. EFSA Journal (2009) 7(12):142

[18] Google immune system organs and see for yourself.

[19] In Milk Matters: infant feeding and immune disorder, I argue the milk hypothesis: that 19th and 20th century artificial feeding has resulted in intergenerationally-compounding immune damage, so that mothers breastfeeding now are affected by their parents’ and grandparents’ infant feeding history and sequelae, and so affect their own children.

[20] https://stm.sciencemag.org/content/8/321/321ra8

[21] Cabrera-Rubio R, Collado MC, Laitinen K, Salminen S, et al. The human milk microbiome changes over lactation

and is shaped by maternal weight and mode of delivery. Am J Clin Nutr, 2012; 96 (3): 544 . DOI: 10.3945/


[22] https://wordpress.com/page/infantfeedingmatters.com/191

[23] Perkin MR, Logan K, Tseng A, et al. Randomized trial of introduction of allergenic foods in breast-fed infants. N Engl J Med. DOI: 10.1056/NEJMoa1514210

[24] It is conceivable that in some cases totally formula fed infants may have fewer obvious allergic symptoms because of the distorted, perhaps suppressed, development of their immune system. To see this as justifying an end to breastfeeding without considering the increased risk of infection, or the effect on developmental trajectories, requires justification the scientific literature does not provide.