Ashley Moran wrote:

> I guess I know far too little to comment seriously on this, but I will
> say that it seems pretty indisputable that we *have* evolved to eat
> certain plants over others, by observing the way some plants make us
> ill, and others don't.  And plants have scattered far and wide in the
> time that humans have done the same.  You might imagine a situation
> where a certain plant "out-evolved" us in Africa, but we encountered an
> edible predecessor in Europe that was not under evolutionary pressure
> to become human-resistant.  This is all speculative on my part, but it
> is just an example of what it means to have evolved to eat a plant
> (which I guess really means that the plant has not evolved to poison
> us).


I think that we, like other creatures, have evolved to be able to handle
certain substances in certain quantities.  That includes macronutrients,
micronutrients, phytochemicals, and various "secondary compounds," which
include antinutrients and toxins.  Some substances, such as phytic acid,
have both good and bad properties.  Consider a food such as spinach.
It's high in oxalic acid, an antinutrient, but also high in folate, a
micronutrient.  It's considered a "paleo" food but, like most other
plant foods, it is not devoid of substances with deleterious effects.  I
guess I'm reacting against the view that paleo foods must, since they
are paleo, contain nothing harmful to us.  The reality is more
complicated.  Paleo and nonpaleo foods contain many of the *very same
compounds* but in different amounts.  For the most part, the plants that
make us ill are the ones that have secondary compounds in concentrations
higher than we can handle.  Cooking and other processing techniques
(soaking, fermenting), reduce the levels of those secondary compounds.
Breeding is another way of accomplishing this.

The issue of molecular mimicry is something else.  Substances such as
gluten cause harm by triggering autoimmune responses in susceptible
persons.  Why are some people seemingly more susceptible than others to
this harm?  I conjecture that it may be more important what we eat when
we are children, and our immune systems are not yet developed, than what
we eat as adults, as far as this sort of thing is concerned.  That is, I
think the child's gut and immune system may be much more vulnerable to
"foreign proteins," and once these systems are compromised, the
vulnerability persists into adulthood.  Maybe a child not exposed to
substances such as gluten in childhood (I know, redundant), is easily
able to eat gathered grains as an adult *because* the digestive and
immune systems were not compromised in childhood.  Yes, it's all
conjecture, but consistent with the findings of, say, Weston Price, who
studied "primitive" people who, as adults, consumed a mix of paleo and
post-paleo foods yet remained robustly healthy.


> You make a good point actually.  I still fail to see, though, why you
> would want to breed an "improved" potato given the huge range of
> perfectly good other vegetables we already have.


People like potatoes, and potatoes have nutrients as well as carbs.  The
mere fact that people like them is a good enough reason to try to
produce varieties that maximize the good aspects and minimize the bad
aspects.

Todd Moody
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