>Various plant foods (and some animal foods) contain compounds
>that are toxins or antinutrients. Stahl refers to these as
>"secondary compounds." What makes a food inedible is not the
>absolute presence or absence of secondary compounds but the
>*level* of them.
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.
And of course many secondary compounds are actually beneficial to humans -
thus the benefits of, for instance, green tea and herbal medicines.
Anne Boyd