Surprising actually but truly makes sense. All those roots, and not just potatoes, demand boiling in order to be easily eaten. They were also the largest and best source of food for a hunter gatherer. Having seen a film of a bushman harvesting a large tuber, it is a safe bet that the land everywhere is full of tubers of some sort.
A local band would soon learn how to identify them. Grains and seeds are much more trouble. At best you can gather a handful or two and then you have to cook them long in order to chew o eat. Until we actually planted those grains it would be too difficult.
Thus the pot would want roots and meat first. Leaves perhaps.
all good.
.
.
The secret to man's intelligence? POTATOES: Humans evolved large brains because our ancestors ate starchy carbohydrates
- Eating meat was credited with allowing humans to develop large brains
- But study suggests cooked starchy foods like potatoes were vital too
- Human brain uses high levels of blood glucose found in carbohydrates
- Starches would have been readily available to ancestral human populations
The human brain is unique - no other animal possesses such a large brain relative to the size of its body.
It
has been argued that an increase in meat consumption could have
triggered the increase in size, but now scientists believe that we may
have another food to thank: the humble potato.
Researchers
suggest carbohydrate consumption, particularly in the form of starch,
was critical for the extraordinary development of the brain over the
past million years.
Big complex brains require lots
of energy to develop and function properly. While synthesis of glucose
from sources other than starch-rich tubers like potatoes is possible, it
is not especially efficient, and such high glucose demands would not
have been met on a low carbohydrate diet
They
say starches would have been readily available to ancestral human
populations in the form of potatoes as well as in seeds, some fruits and
nuts.
The
new study combines archaeological, anthropological, genetic,
physiological and anatomical data to argue it carbohydrate consumption
was key in the human brain's evolution.
Up
until now there has been a heavy focus on the role of animal protein
and cooking in the development of the human brain over the last two
million years and the importance of starch rich plant foods has been
largely overlooked.
Dr
Karen Hardy and her team at the Autonomous University of Barcelona say
that there are five crucial reasons why a starch-rich diet was critical
in human development.
Firstly,
the human brain uses up to 25 per cent of the body's energy daily
budget and up to 60 per cent of the body's blood glucose.
While
synthesis of glucose from other sources is possible it is not
especially efficient, and such high glucose demands would not have been
met on a low carbohydrate diet.
This need for carbohydrates would have been satisfied in part by the development of cooking.
While
raw starches are often poorly digested in humans, when cooked they
lose their crystalline structure and in turn make the assimilation of
nutrients much easier.
The
ability to use fire for cooking would have unlocked nutrients and
enabled our ancestors to eat a far broader diet including tough, starchy
roots.
Pregnancy and breastfeeding also place additional demands on the body's glucose budget.
Low
maternal blood glucose levels compromise the health of both the mother
and her offspring, which suggest that a certain level of carbohydrates
would have been essential for survival.
In
addition to this, starchy carbohydrates would have been readily
available to ancestral human populations in the form of tubers, as well
as in seeds and some fruits and nuts.
The human brain uses up to 60 per cent of the body's blood glucose. It is thought that cooked starchy food like potatoes could have provided a glucose-rich diet necessary for this to develop in our early ancestors
The researchers also point out that humans possess six salivary amylase genes, while other primates just have two, increasing the ability to digest starch.
The
exact date at which these additional genes appeared remains uncertain,
but analysis suggests it was at some point in the last million years.
Dr
Hardy explained that after cooking became widespread and the salivary
amylase genes multiplied, this increased the availability of dietary
glucose to the brain and foetus which, in turn, allowed the acceleration
in brain size which occurred from around 800,000 years ago onwards.
She
said: 'In addition to the increased energy availability from starch,
other advantages of the coevolution of cooking and amylase expression
include a reduction in chewing time, increased palatability and
digestibility of polyphenol-rich plant foods, and improved reproductive
function; a reliable supply of glycemic carbohydrate is likely to have
sustainably supported foetal growth, provided the extra caloric intake
needed during lactation, and improved infant survival.
'The
regular consumption of starchy plant foods offers a coherent
explanation for the provision of energy to the developing brain during
the Late Pliocene and Early Pleistocene while the development of
cooking, and a concomitant increases in salivary amylase expression,
explains how the rapid increases in brain size from the Middle
Pleistocene onward were energetically affordable.'
Added
Dr Hardy: 'Eating meat may have kick started the evolution of bigger
brains, but cooked starchy foods together with more salivary amylase
genes made us smarter still.'
The study was published in The Quarterly Review of Biology.
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