On Fri, 8 Feb 2002, Boyd, Anne (Cahners) wrote:

> That's interesting - would the essential oils in herbs and the like be
> considered 'secondary compounds'?  That would explain why those substances
> act as a deterrent to insects and some animals, but not to humans, unless
> eaten in excess.  I believe parsley is one herb that is toxic if you eat too
> much.

Yes, I think this are good examples.  Insects consume these
compounds at what is, for them, megadose levels.  If we consumed
them at similar dosages, we'd have problems.  Oxalic acid is an
antinutrient, like phytic acid, that binds with minerals and
inhibits their absorption.  It is present in some leafy greens
and some citrus fruits, but not in amounts that we can't
tolerate.

> And of course many secondary compounds are actually beneficial to humans -
> thus the benefits of, for instance, green tea and herbal medicines.

Here too the dosing level can be critical.

Stahl points out that the "neurotoxins" in some legumes, such as
cholinesterase inhibitors, are also present in broccoli, turnips,
radishes, asparagus, tomatoes, eggplant, carrots, celery,
oranges, apples, and raspberries -- but in small amounts.  The
idea that these neurotoxins are present in legumes but absent in
allegedly "paleo" foods is just wrong.

Todd Moody
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