> Such a contemporary malnutrition amoung a indigenous population needn't
have
> to do with the properties of their traditional staple.
> They will have adopted some bad "westernized" habits, like sugar, alcohol
> etc..

This is a bit ingenuous. malnutrition in children is not due to consumption
of sugar or alcohol; if anything it would help these unfortunates.

> Most of the native american "indians" were agricultural,
> and they had it well developped beautifully within their genetical
> resources.

what do you imply by "agricultural"? that most of their calories were
derived from plant foods? name one group where this is true. [well, apart
from the Tarahumara, in whom the result of a plant diet is clear].
>
> In the case of your corn people however I think the special properties of
> corn (we call it maize) can well explain deficiencies.
> It's certainly not a deficiency of protein.

no, but it certainly is the protein quality. any decent nutritionist knows a
corn gruel diet leads to kwashiorkor, due to the profound inferiority of the
amino acid balance. i think the problem is lysine as well as tryptophan.

> 2400 kcal of maize yield 64g protein, that's 117% RDA. Together with some
> beans (as native in the Americas) they make up an excellent protein with a
> quality like egg (which is 10% better than muscle meat).

i dont believe this, but can you provide a reputable reference for protein
complementarity? undoubtedly the beans help a good deal.

>
> But the problem is niacin.
> Niacin in maize (and millet) isn't available without a special treatment
> (which some mexican tribes had adopted).

Since, as has been pointed out, they would have treated it with lime, would
this be the core of the problem? apart from protein quality, it may be more
an issue of vitamin A and iron shortage.  I'm hoping to find out further
exactly what goes wrong with the Tarahumara. i do know 50% of the expectant
mothers are anaemic. Only about 2% of iron from plant sources is able to be
metabolized. and the conversion of beta-carotene to vitamin A [remember, no
plants have vitamin A] occurs at 8:1 ratio in good health. a kilo of maize
does not provide adequate vitamin A equivalent [about 4,000 units].

Seems that the Tarahumara were driven out of previous lands into more
inhospitable territory, where presumably there was less access to freshwater
fish.   The answer to Todd's surmise re their low rate of cardio disease may
be simply that they dont live long enough to get heart problems.   meanwhile
they stand as a pretty good explanation of why no native groups, anywhere at
any time, *preferred* to get the bulk of calories from plant sources.

andrew