>I've heard that the oxalic acid in greens such as spinach interfere with
>calcium absorption in foods such as sesame seeds. Any opinions?

Some nuts and greens are free of/low in oxalates.  I am very careful about
giving Pamela these foods and not those containing oxalates.  Here's the
list I got out of "Prescription for Nutritional Healing":

buckwheat, dandelion greens (you can make a tea that's bitter though),
flounder, salmon and sardine with bones ;-P, molasses, tofu, broccoli, kale,
turnip greens, sesame seeds, hazelnuts, etc.  The ones to watch are almonds,
beet greens, cashews, chard, rhubarb and spinach.  I do know that bok choy
is high in calcium, but I'm not sure if it contains oxalates.

Tammy G.

"A parent's love perceives no limitations."