Todd Moody said that
 >>In general, oxalic acid is highest in green leafy stuff, which is ironic
since it inhibits the absorption of calcium and these
foods are supposed to be the some of the best non-dairy sources
of calcium.

I would clarify, that oxalic acid content is high in ONLY some leafy greens:
spinach, chard, and beet greens.  There are very calcium rich leafy greens
and flowering vegetables which do not contain oxalic acid.  Examples include
bok choy, tot soy, broccoli, kale, collards, and mustard greens.  This
second list of greens is also more nutrient dense than the first---besides
calcium, there are other minerals in abundance in these greens.

I have noticed that spinach often leaves a funny taste on my tongue and
makes my teeth feel sensitive if I eat a lot of it.  Beet greens and chard
can do the same.... I never get this from the non-oxalate rich greens listed
above.

Rachel