On Mon, 19 Jul 1999, Jacques Laurin <[log in to unmask]> wrote:
> I would appreciate comments on this text about the problems of cooking.
>
> "Through the working of natural selection, each species adapts to the
> conditions of its habitat. Such adaptation, however, takes many
> generations ; the genetic code changes very slowly over time (less than
> 1 % in the six million years since our forebears diverged from the
> chimpanzees). The practice of cooking is quite recent in relation to the
> biological time scale, each new alimentary challenge introduced by
> intelligent artifice may pose a new metabolic problem and entail
> pathological consequences.

I'm not convinced that alimentary change is that much of a challenge.  For
one thing the 1% change is across the entire genome and we don't know the
percentage difference in the minority of the genome which is coding and
this is the important figure in terms of adaptive difference. Secondly the
gorilla diverged from humans and chimpanzees at about the same time, but
the three species have very different diets, body sizes (including extent
of sexual dimorphism), mating patterns, etc, and all those differences
presumably have a genetic basis within the 1% difference.

> For any culinary artifice, there is a reason to ask :
>
> whether a genetic adaptation has been or would have been necessary

OK

> whether such adaptation is possible
> whether it has had time to occur

I don't think we can necessarily expect to answer this, we know so little
about the genetic basis of differences in diets that we can hardly begin
to guess what isn't possible.  Given the differences already present
between species, it seems likely that given enough time most things are
possible.  But at present we can't predict a priori how much time is
enough.

> This issue, apparently ignored by medical research, is quite critical,
> being at the very heart of the world health problem. The prognosis in
> any illness depends inevitably on nutrition.  Therefore the illness
> depends on nutrition (even if one is ignorant of its mechanisms). It is
> helpful, then, to pose the problem of adaptation before plunging blindly
> into a quest for therapeutics that risk missing the point, that in fact
> remain unavailing in the face of various diseases. Three quarters of the
> population die of neoplastic or cardiovascular diseases, which are not
> necessarily preordained by nature.

According tothe World Health Organization "World Health Report 1999"
Appendix on mortality (http://www.who.int/whr/1999/en/pdf/mortality.pdf)
Mortality in WHO member countries in 1998 is estimated at:
        Communicable diseases, maternal and perinatal   30.5%
           conditions and nutritional deficiencies
        Noncommunicable conditions                      58.8%
          To which neoplasms contribute 13.6% and cardiovascular
          diseases 30.9%
        Injuries                                        10.7%

Thus 44.5% of the world population die of neoplastic or cardiovascular
disease - hardly three-quarters!  However, many of the other
non-communicable causes have a dietary component in their etiology, eg
diabetes, asthma.

> Non-original foods introduce molecules into the organism to which the
> enzymes, programmed by the genetic code, have no reason to be adapted.
> These "non-original molecules" may be created in chemical reactions
> induced by cooking, or may come from foods not in the original
> alimentary spectrum of humans (such as animal milk). It will be
> impossible for some of these to be metabolized normally ; instead,
> blocked at some stage of transformation, they will accumulate in the
> organism, provoking a gradual culinary intoxination. They will be found
> in the circulating fluids (blood, lymph) or stored within the cells or
> in the interstitial spaces (amylose), in fatty deposits, or even
> integrated into cell and tissue structures (membranes, collagen, joints,
> dentin, etc...)

They may get into tissue structures but the collagens are a set of protein
molecules with a specific structure - other molecules cannot get into
them.  One or more examples would help your argument here: one might
naively suppose that all ingested proteins are denatured in the digestive
system, and all are then hydrolysable by enzymes - so what is there in
animal milk that gets into the body?  The substance which springs to mind
as fitting your description is lead, which accumulates over a lifetime
because humans have no excretion mechanism for it.

(Rest deleted - I can't comment on it)

Andrew Millard

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 Dr. Andrew Millard                              [log in to unmask]
 Department of Archaeology, University of Durham,   Tel: +44 191 374 4757
 South Road, Durham. DH1 3LE. United Kingdom.       Fax: +44 191 374 3619
                      http://www.dur.ac.uk/~drk0arm/
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