Most People seem to agree that we cannot and do not want to go back to the past, but the reason given is often wrong; that time has moved on and what was can never be again. The truth is that we cannot go back to what we never left. Our home is the earth, our time the Pleistocene Ice Ages. The past is the formula for our being.
(Paul Shepard)

Monday, 9 January 2012

stature


Sources on request
Declaration of interests; being a short arse.
What is driving the modern rise in stature?
The mantra of the Paleo food movement, the mantra of good science, “correlation is not causation”. This mantra is hugely important for a hunting hominid that searches for patterns to make fast, often life or death, decisions. We must bear this in mind………
Every so often some paleo person or health person makes statements which cause me to wince. Statements about “competing for mates” simply leave me shaking my head particularly if the writer means wrestling over women. This is simply an extrapolation from primate behaviour which does not fit in with observed forager behaviours. N.Changon noted combat success did not equate to reproductive success in the horticulturalist Yanomamo. Hunting success can be a factor and is often adjudicated by the “brides” parents. Any talk of Alpha males is particularly inappropriate for humans and is usually a rationalisation for boorish behaviour.
Today however I am going to talk about the notion that Palaeolithic peoples were tall and from the Mesolithic or Neolithic population heights can be characterised by their downward trend until the later 20th century when they have “returned” to their Pre-agricultural levels. (Just to clarify some Palaeolithic hominids were tall and powerful such as H.heidelbergensis and some were short and powerful H .neanderthalensis. H.Sapiens is really who we are interested in and this is who is being discussed). Daniel Vitalis who I think is a wonderfully charismatic speaker and excellent source of knowledge and wisdom talks about a decline citing reduced height brain capacity and muscularity. He says that agricultural and industrial humans are so degenerate that we should be re-classified as H.sapiens domesticus. Though he is right about brain size (some small decrease from European “Cro-Magnon” this is not necessarily a sign of degeneracy as both H.heidelbergensis and neanderthalensis had brains that matched our own and in some cases were bigger but were not necessarily as well co-ordinated. I agree about muscularity though this would seem to be predominantly environmental.
As a quick aside a domesticated animal has been manipulated on a genetic level (via breeding) to produce qualities necessary for the domesticator. I am unaware of any widespread breeding programmes among human populations which by virtue of our slow reproductive rates would need to be on a very long timeframe. Any Genetic changes in human populations have been the result of evolutionary pressure rather than selective breeding; while I have sympathy for the domesticus argument as a rhetorical tool I don’t think that it is a valid assertion. My daughter raised by hunter gatherers would be indistinguishable from them in the way a dog raised by wolves wouldn’t be.
However the changes to a perhaps more gracile, smaller brained and shorter (I’ll get back to this) animal all seem to have occurred within the Palaeolithic. There does appear to be a difference between western and eastern Europeans in that westerners seem to have got shorter. Diet and genetic flow are often used to account for this. I can’t think of any substantial differences in diet between the populations save for possible mammoth exploitation in Poland and the Ukraine
. In the west there is a decline in height in the Mesolithic when for a time life seems to have become more challenging with massive environmental shifts and increasing pressure for land. With generally no increase in population pressure for space may have come from reduced land mass and the possible ‘bow wave’ of the Neolithic. The Mesolithic marks intensification in the shift towards marine resources and possible greater exploitation of plant resources with a richer biomass. Violence and territoriality are also present in some areas, Scandinavia in particular
We could easily posit that the pressures of the Mesolithic were a factor in the reduced height of western Europeans at this time. Mesolithic hunters as a rough rule averaged from 160-170cm but still maintained the general good health of hunting peoples. Heights and characteristics that are shared by modern hunting peoples. Isotopes suggest that, for the early Mesolithic at least, diet remained consistent with the Palaeolithic.
In Britain at least heights did not decline in the Neolithic but actually remained stable, though health declined substantially. Heights rebounded in the Bronze Age with the favourable climate and then moved up and down in sync with the prevailing climates. Farming, though hardly good for one’s health it seems, in Britain at least, is not necessarily bad for one’s height.
The far more intense stratification of society in the East may have suppressed the population’s overall height. Mycenaean nobility (from isotopes, big meat eaters) were a full 10cm taller than the general population who slaved and toiled on grains. Never forget that grains are the food of the slaves.
The hominids formerly known as Cro Magnon averaged from 166-171cm tall this is a little shorter than the “red lady” at 174 but more strongly built, but all these people would be short compared to a modern European or American. DNA shows that modern Europeans (and European Diaspora) share at least 80% of our DNA with these people so we can say that we have not only attained pre agricultural heights but superseded them.
A good thing? Now this is where it gets interesting being tall is generally considered to be a marker of good health. It is so desirable that it is part of our lexicon “stand tall” “high and mighty” my daughter is according to the charts going to be a strapping young lady and I am really happy about this.
Of course you can see the ‘BUT’ coming a mile of. Height correlates very badly with CHD and cancer ratesAll the populations of modern Foragers and horticulturalists who have been found to have no or little heart disease or DoCs (diseases of civilisation) are shorter on average than modern western populations. Most if not all centenarians are shorter in stature study after study has shown that as a populations height increases so does the prevalence of DoC’s. Remember our mantra!
Study after study (China Crete Sweden Japan Fiji and on and on) shows that as height increases so do diseases of civilisation, indeed height is another factor which was ignored or discounted by Ancel Keyes in the “7 countries study”. The famous “good health” of the Norwegians in the war years was accompanied by a decrease in stature for people living then.
Heights haven’t just increased over the past 150 or so years they have exploded upwards they have increased by 10 and more centimetres in many European countries accompanied with increasing CVD deaths.
Male heights 19th century-present
Norway 1.69 m (5 ft 6 12 in)-’ 1.820 m (5 ft 11 12 in)
Sweden 1.68 m (5 ft 6 14 in)- 1.779 m (5 ft 10 in)
Netherlands 1.64 m (5 ft 4 12 in)- 1.799 m (5 ft 11 in)
Scotland 1.68 m (5 ft 6 14 in)- 1.750 m (5 ft 9 in)
Germany 1.64 m (5 ft 4 12 in)- 1.810 m (5 ft 11 12 in) (19 year olds)
England started eating white flour(and sugar)in large quantities far earlier than other countries and the height jump was not so nearly pronounced from 1.72 m (5 ft 7 34 in) to 1.776 m (5 ft 10 in)
Now of course I am not saying that an increase in height causes, well anything and to be frank while I thought this was interesting my jolly old mantra of correlation not= causation was running through my head as many factors have changed at the same time. Until I read from Boyd Eaton that Inuit heights had only increased since the addition of refined flour and sugar into the diet. That addition of western foods into traditional diets causes not only greater Doc prevalence but also increasing heights and then…… . It is interesting to note that, though modern humans have returned to the body stature of their Early Paleolithic ancestors, they retain the modern proportions with short forearms and short crural segments.
So the increase in height is not a return to the proportions of our Paleolithic forebears but an increase in stature perhaps driven by a different agent. Clearly I have not written this to cause anyone sleepless nights or to hopelessly confuse the issue, if it carries any weight I actually believe that CVD and most diseases of the heart are caused by stress then smoking and way…way down the list diet. The Authors of the studies I have linked to show confused data relating to diabetes and height, though the increases in weight and BMI which accompany these increase are markers for this modern problem.
The authors point to IGF (insulin growth factor) as a possible cause for the jumps in human height that accompany adoption of western food. Indeed as HG peoples seem to have no real difficulty attaining decent calorific intakes despite some periods of shortage it is hard to write it off simply as “surplus calories”. Though It may be that grain eating peoples retained their short statures or got shorter due to the calorific and nutritional poverty of the Neolithic/agricultural diet and its attendant periods of growth arresting starvation. While periodic shortage is attested to in HG teeth growth arrest (seen in the long bones) is not commonly seen. A single dietary or macronutrient factor among such populations is hard to point at as we have a range of compositions from 70% fat to 20% and inverse for carbohydrate (almost always tubers and veg). All populations save modern western populations are physically active leaving refined grains as the single or main probable cause.
Diets high in refined carbohydrates have affected pregnant women (who divert glucose to their developing children) Finally, in healthy pregnant women, a high-GI diet is associated with higher birth weight and infant ponderal index than a nutrient-balanced low-GI diet [98]. In this way, epigenetic changes brought about by differences in diet composition during pregnancy could promote acceleration of obesity from one generation to the next” Brand-Miller JC, Griffin HJ, Colagiuri S: The carnivore connection hypothesis: revisited. J Obes 2012, 2012: 258624. It is worth noting that both large and small children have diabetes problems and the children of diabetics have larger than average children.
Height I would think does not influence or cause cardio vascular disease BUT the factors that have caused the increase in this problem may be at the root of the jump in heights that accompany increases in these diseases. I have mostly written this to deal with the repeated claim that our Paleolithic ancestors were tall as or taller than modern Euramericans, which is, from the fossil record at least, untrue and from correlations across populations perhaps undesirable. It is also more than possible that greater height where fueled by refined carbohydrates is a symptom of great metabolic distress resulting in higher rates of at least some diseases of civilization.

No comments:

Post a Comment