Early Human Development 88 (2012) S57–S59

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Early Human Development

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A short history of infant feeding and growth

Lawrence Weaver 1

Royal Hospital for Sick Children, University of Glasgow, UK

1 Lawrence Weaver is the Samson Gemmell Professorsity of Glasgow. He was formerly a member of the scientrition Unit in Cambridge and is co-author of Feeding andChildren (WHO 2000). He is a Doctor of Medicine (MDbridge and a Doctor of Science (DSc) from the Universitydiatrician at the Royal Hospital for Sick Children andFellow in the Centre for the History of Medicine of the

0378-3782/$ – see front matter © 2012 Elsevier Irelanddoi:10.1016/j.earlhumdev.2011.12.029

a b s t r a c t

Our modern understanding of infant nutrition and feeding arose out of a constellation of scientific discoveriesmade more than 100 years ago. With the emergence of chemistry and physiology in the late 18th century, theanalysis of foods, metabolic and energy balance studies, calorimetry, cell theory and measurements of growthand digestive function, became integrated to provide a coherent model of how organisms grow and are nour-ished. The interaction, with clinicians and public health professionals, of those working in these ‘new’ areas ofthe biological science, led to the application of safe and effective ways of feeding babies and of monitoringtheir growth and development, in the face of, and in response to, high infant mortality and morbidity

© 2012 Elsevier Ireland Ltd. All rights reserved.

1. What inspired efforts to measure babies' weights? [1]

The reason people started recording the weights, lengths andgrowth of babies in the early nineteenth century was because of con-cern about infant and child mortality. As measurements started to becollected it became clear that a lot of babies who were dying weremalnourished and underweight. They were dying of various diseases,many were very poorly fed, and the babies that were not breast fed,especially, did not thrive and often died young. Statistics on infantmortality linked to measures of birth weight and growth, documentedthe relationship between poor infant feeding, poor growth and highmortality in early life. The supply of clean, pasteurised, modified cow'smilk to mothers who could not or did not want to breast feed wentsome way to reducing infant mortality rates.

2. What are the health implications associated with infancygrowth? [2]

The weight of a newborn baby is a general index of its health atbirth. As well as body weight, body length and a whole lot of othergrowth indices (such as head and abdominal circumference) are to-gether a reflection of how a baby has grown in the womb. Birth is apoint in time during the growth of a baby from conception to adult-hood. At birth, of course, the baby becomes dependent on mother tofeed him or her and the rate at which that baby grows in weight is

of Child Health at the Univer-tific staff of the MRC Dunn Nu-Nutrition of Infants and Young

) from the University of Cam-of Glasgow, a consultant pae-an Honorary Senior ResearchUniversity of Glasgow.

Ltd. All rights reserved.

a reflection of the development of its skeleton, fat stores, brain,heart, liver, muscles etc and all the organs of the body. The weightand length of the baby are just a simple summation of all these things.It follows therefore that if a baby is growing sub-optimally in weightand/or length, it is likely that something that should be happening inits development is not happening. A baby that does not put on weightafter birth is not acquiring enough or the right food to build its bodyproperly. This may also deprive it of the right nutrients for normalbrain development, for instance, with consequences for its IQ. Babiesare built out of the food (mostly milk to start with) that mothers givethem.

About thirty years ago it was noted babies that were born small(lighter than the average), and were still small at one year, weremore likely than normally-grown babies to have certain chronicadult diseases in later life: ischaemic heart disease, high blood pressure,obesity and diabetes. There was a correlation noted between beingsmall at birth and dying early in adulthood of chronic vascular andmet-abolic diseases.

Over the last twenty years a lot of research has been done intowhat it is that explains this relationship, and it has been suggested re-cently that the rate at which a baby grows in the first year may be amore important determinant of its risk of disease in later life, thanits birth weight alone. An explanation for this is that if you growfast early in life, to ‘catch-up’, you ‘pay a penalty’ later on; the socalled ‘grow now, pay later’ hypothesis. There is a ‘cost’ to catching-upwhich you have to pay back later on in terms of premature ill health.Now that makes sense biologically because nothing is ‘free’ — if youdo some things at some point in the life course, they may demand a‘pay-back’ later on. If you go into puberty late, your final adult heightwill be achieved later on, for instance. It is a fact of biology, that body de-velopment in early life is ‘plastic’ and there are different patterns ofgrowth that can lead to adult weight and stature. It looks like theremay be a relationship between rate of early growth and later healthwhich suggests that accelerated growth in infancy may be deleterious.

S58 L. Weaver / Early Human Development 88 (2012) S57–S59

3. How have the growth rates of babies changed over the lastcentury? [3]

The rates and patterns of growth in weight of European and NorthAmerican infants have changed over the last hundred years. Since thedevelopment and first use of growth charts for postnatal health sur-veillance there appears to have been an increase in the weight ofone year olds of about 1 kg. Taking into account the higher pastrates of infant morbidity and mortality, and poorer quality of artificialfeeds, this change is likely to be another expression of the secular in-crease in physical stature consequent upon improved hygiene andnutrition. Using the new WHO standards of infant weight growth,this secular change can be observed for both breast fed andformula-fed babies. The slower weight growth of the former, bothnow and in the past compared with modern formula-fed babies,may have implications of our understanding of the risk factors forobesity and cardiovascular disease. However the variability of infantgrowth in time and space, and the plasticity of developmental pro-cesses during the life course (foetal life, infancy, puberty, reproduc-tion), mean that the WHO infant growth standards cannot alone beregarded as an ideal for all babies.

4. How do babies growth rates vary ethnographically today? [4]

There are major differences in the rates at which babies grow inpoorer developing countries, where weaning foods are very poorlyconstituted and often contaminated with bacteria. While babies arebreast fed they do well, and humanmilk is a sole and sufficient sourceof milk for most babies until about six months. However babies haveto be weaned onto other foods sooner or later, and in many parts ofthe developingworldmothers useweaning foods that are of low energydensity and bacterially contaminated, and their babies get diarrhoea,fail to thrive, and show ‘growth faltering’. In the developed world, onthe other hand, that is unusual, because when mothers wean theirbabies, and/or do not breast feed them, they have access to clean andproperly formulated milks and weaning foods which are as good, interms of ensuring weight growth, as breast milk, if not ‘better’. Babiesthat are formula-fed tend to end up bigger than babies that are breastfed. Also, in the developed world, weaning foods come in little jarsfrom supermarkets that are clean and of balanced nutrient composition.So there are major differences if you look at the extremes, betweenbabies ofwell-to-domums inmuch of Europe andNorth America for in-stance, and babies of poorer mothers in the developing world who donot have access to clean water and nutritionally well-constituted babyfoods and are at high risk of infant infection.

5. What factors influence a baby's growth rate? [5]

The main factor that determines weight growth rate is whatbabies are fed, ie, the nutritional composition and quality of thefood and its cleanliness, and whether it has bacteria or other harmfulthings in it. It is poor feeding and disease that largely account for poorweight growth of babies. Genetics is not really an important factor de-termining growth rate during infancy. Formula-fed babies tend to bebigger than babies breast fed, but why is this?

That is an easy and difficult question to answer. The easy answer isthat they are fed too much. If the baby is not ‘demanding’ the milk (asit does on the breast) and it is delivered in a bottle, the baby has lesscontrol over what it takes, and it is easy for the mother to overfeedher baby. In the past infant formulas were more energy-dense (withmore calories in them). Moreover the milk that goes into the babyfrom a bottle is of exactly the same composition at the beginningand end of a feed, whereas mother's milk from the breast changesthroughout a feed. It starts off with a fat composition of about 2%and ends up at 4 or 5% and that rising fat level is thought to operateas a signal to stop the baby feeding.

Breast milk contains a lot of ‘bioactive’ living substances which dothings other than just nourish the baby. It is too narrow to think ofmilk as just food. From an evolutionary point of view, milk is probablymuch more important as a substance to protect babies from infec-tions. Babies that are breast fed have much greater protection againstinfection because of all the protective factors in human milk. Breastmilk also contains a lot of other bioactive substances that may helpto accelerate or modulate the development of various body systems(including the nervous system) such as specific fatty acids for thephospholipids in the brain. These seem to affect neurodevelopmentand there is some evidence that if you are exclusively formula-fed,your IQ and visual acuity are lower than if you are breast fed. Thereare numerous well documented advantages of human milk tohuman babies. The downside of formula milk is particularly strongin infants born prematurely and of low birth weight, which are athigher risk of various gut diseases, particularly necrotising enteroco-litis and cow's milk protein intolerance. Cow's milk (the basis of for-mulas) is for calves and human milk is for babies.

6. There is wide variability in the growth rates of infants. Do youbelieve there is an ideal growth rate? [6]

The WHO growth standards are the biggest, best and most sys-tematically collected data on how babies grow in weight and length.They are an enormous achievement, both in the undertaking of theproject to collect the data and also in the analysis and presentationof them. They represent the growth of healthy exclusively breast fedbabies of mothers who were healthy, non-smoking and cared wellfor their babies.

They are an ‘ideal’ in the sense that they represent a measure ofhow healthy babies throughout the world grew in the 1990s whenthey were collected, and are a ‘standard’, to which all infants can as-pire to. But there is variability in biology that teaches us that nothingis fixed, that the rate and pattern at which a baby grows now in thepresent circumstances may not necessarily be the ideal pattern ofgrowth of all babies for all times. When a comparable study is done,say in 50 years time, infant growth rates may well have changed.They may change, for instance, because of secular changes in mater-nal height, leading to changes in infant birth weight, and evenchanges in mother's lactational capacity, quite apart from culturalchanges in weaning practices.

A lot of different things may happen to early human developmentin the future (as they have in the past), and weight growth itself isone measurable index of the life course. It is just a measure of howbig a baby gets over time. It does not tell us much about the develop-mental changes that are going inside the baby, which are also subjectto secular changes over time, related to feeding (duration of milkfeeding and time of weaning) and exposure to infection, that are driv-en by environmental and cultural forces that shape the evolution ofspecies.

Human milk is undoubtedly the best food for human babies, butbecause there is variability and plastically in growth, geographicallyin place and temporally over time, it is likely that patterns of earlygrowth will continue to change. From biological and cultural pointsof view, we know that nothing stays still, and there is no reasonwhy a single measurement, like weight growth in infancy, shouldstay absolutely fixed over time. This fact does not invalidate thevalue of the current WHO growth charts but it does suggest thatthey are not the ‘last word’, anymore than any measurement of any-thing in biology or medicine or nutrition is the ‘last word’.

Conflict of interest statement

There is no conflict of interest.

S59L. Weaver / Early Human Development 88 (2012) S57–S59

References

[1] Weaver LT. ‘In the balance’: weighing babies and the birth of the infant welfareclinic. Bull Hist Med 2010;84:30–57.

[2] Weaver LT. Rapid growth in infancy: balancing the interests of the child. J PediatrGastroenterol Nutr 2006;43:428–32.

[3] Weaver LT. How did babies grow 100 years ago? Europ J Clin Nutr 2010;65:3–9.[4] Fleischer Michaelsen K, Weaver LT, Branca F, Robertson A. Feeding and Nutrition of

Infants and Young Children. WHO Regional Publications, European Series No 87.Geneva: WHO 2000.

[5] Weaver LT. The emergence of our modern understanding of infant nutrition andfeeding 1750–1900. Cur Pediatr 2006;16:342–7.

[6] Weaver LT. State of the art of growth standards. In: Recent Advances in Growth Re-search: Nutritional, Molecular and Endocrine Perspectives, Gillman M, Gluckman P,Rosenfeld R (eds). Nestlé Nutrition Institute Workshop Series Pediatric Program,Vol 71, Basel: Karger 2012 (in press).