Posts Tagged ‘Nutrition’

Nutrition rather than genetics when it comes to height over the last 100 years

September 2, 2013

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.

Nature and Nurture

Nature and Nurture

Science Codex: 

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

Canada used indigenous children to “study” malnutrition

July 28, 2013

Yet another depressing story of how, in the name of “science”, the “establishment” made use of less “worthy” populations to carry out medical experiments.

This time in Canada from 1942 -1952.

There was no difference of principle and only one of degree between the medical experiments carried out in Nazi Germany and those carried out on native or disadvantaged populations in Australia, Canada, and the USA (among many other countries).

We may like to think that it does not happen any more. I am not so sure. The real story of Haiti and its cholera and the use of cheap, untested vaccines is yet to be told Similarly, some of the stories about the intentional “creation” of new strains of influenza and the subsequent discovery and dissemination of new vaccines for their cure may never ever become public.

Mosby, I. Social History 46, 145–172 (2013). Administering Colonial Science: Nutrition Research and Human Biomedical Experimentation in Aboriginal Communities and Residential Schools, 1942–1952

Abstract: Between 1942 and 1952, some of Canada’s leading nutrition experts, in cooperation with various federal departments, conducted an unprecedented series of nutritional studies of Aboriginal communities and residential schools. The most ambitious and perhaps best known of these was the 1947–1948 James Bay Survey of the Attawapiskat and Rupert’s House Cree First Nations. Less well known were two separate long-term studies that went so far as to include controlled experiments conducted, apparently without the subjects’ informed consent or knowledge, on malnourished Aboriginal populations in Northern Manitoba and, later, in six Indian residential schools. This article explores these studies and experiments, in part to provide a narrative record of a largely unexamined episode of exploitation and neglect by the Canadian government. At the same time, it situates these studies within the context of broader federal policies governing the lives of Aboriginal peoples, a shifting Canadian consensus concerning the science of nutrition, and changing attitudes towards the ethics of biomedical experimentation on human beings during a period that encompassed, among other things, the establishment of the Nuremberg Code of experimental research ethics.

Nature also reports:

Canadian government scientists used malnourished native populations as unwitting subjects in experiments conducted in the 1940s and 1950s to test nutritional interventions. The tests, many of which involved children at state-funded residential schools, had been largely forgotten until they were described earlier this month in the journal Social History by Ian Mosby, who studies the history of food and nutrition at the University of Guelph in Canada.

The work began in 1942, when government scientists visited several native communities in northern Manitoba and discovered widespread hunger and malnutrition. “Their immediate response was to study the problem by testing nutritional supplements,” says Mosby. From a group of 300 malnourished people selected for the tests, 125 were given vitamin supplements, and the rest served as ‘untreated’ controls. ….

Nancy Walton, a medical ethicist at Ryerson University in Toronto, Ontario, and former chairwoman of the university’s research-ethics board, says that such a project would never be allowed today, “but in the context of that time, it’s unfortunately not surprising”. Awareness of the need for informed consent in human studies was growing — informed consent was a central tenet of the Nuremberg Code, developed in the late 1940s — but the idea had not yet been adopted around the world.

“It’s not just bad ethics, it’s bad science,” Walton says of the Canadian government research. “They didn’t appear to try and prove or disprove any hypothesis that I can see, or make any statistical correlations.”

Indeed, says Mosby, very little of value came out of the research. He found no evidence that the northern Manitoba study was completed or published. The school experiments were presented at conferences and published, but they led to no important advances in nutritional science or improvements in conditions at the schools. “They mostly just confirmed what they already knew,” Mosby says. ….

 


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