Nutrition – and especially nutrition in the early years of life – has dominated the development of human height over the last 100 years. An average growth of 11 cm in the last 100 years. One hundred years is just over 5 generations and far too short a time for Darwinian genetics to have had any significant impact. This increase in height, rather than being hampered, actually accelerated during 2 World Wars and the Great Depression in the 15 European countries studied.
But now as the height impact of improved nutrition plateaus, perhaps the next 100 years and five generations of fast food will bring an 11cm increase in human width!!
In the “nature” versus “nurture” debate it only convinces me further that for all genetic traits, the particular set of genes in an individual only provides a Bell curve of the available framework for the expression of that trait. And there will be a Bell curve for each “trait” which is genetically determined. Thereafter it is “nurture” and/or the existing environment which determines the level to which that trait is expressed.
The average height of European males increased by an unprecedented 11cm between the mid-nineteenth century and 1980, according to a new paper published online today in the journalOxford Economic Papers. Contrary to expectations, the study also reveals that average height actually accelerated in the period spanning the two World Wars and the Great Depression.
Timothy J. Hatton, Professor of Economics at the University of Essex and the Research School of Economics at Australian National University in Canberra, examined and analysed a new dataset for the average height (at the age of around 21) of adult male birth cohorts, from the 1870s to 1980, in fifteen European countries. The data were drawn from a variety of sources. For the most recent decades the data were mainly taken from height-by-age in cross sectional surveys. Meanwhile, observations for the earlier years were based on data for the heights of military conscripts and recruits. The data is for men only as the historical evidence for women’s heights is severely limited.
Professor Hatton said, “Increases in human stature are a key indicator of improvements in the average health of populations. The evidence suggests that the improving disease environment, as reflected in the fall in infant mortality, is the single most important factor driving the increase in height. The link between infant mortality and height has already been demonstrated by a number of studies.” Infant mortality rates fell from an average of 178 per thousand in 1871-5 to 120 per thousand in 1911-15. They then plummeted to 41 in 1951-5 and 14 in 1976-80.
In northern and middle European countries (including Britain and Ireland, the Scandinavian countries, Netherlands, Austria, Belgium, and Germany) there was a “distinct quickening” in the pace of advance in the period spanning the two World Wars and the Great Depression. This is striking because the period largely predates the wide implementation of major breakthroughs in modern medicine and national health services. One possible reason, alongside the crucial decline in infant mortality, for the rapid growth of average male height in this period was that there was a strong downward trend in fertility at the time, and smaller family sizes have already been linked with increasing height.
Other factors in the increase in average male height include an increased income per capita; more sanitary housing and living conditions; better general education about health and nutrition (which led to better care for children and young people within the home); and better social services and health systems.
Source: Oxford University Press