I just read for the first time in a general, omnivore article the reference to a high-protein diet leeching calcium.
This has always been my best defense against the “If you don’t drink milk, how do you get your calcium?” poser. A high-protein diet raises your acidity, and your bones will shed calcium at a greater rate. As a woman who’s been through two rounds of chemically induced menopause (long story—Tom deserves a medal for not leaving me because I was so crazypants), calcium intake is always on my mind. If I go without tofu, tempeh, kale, or fortified OJ (how much molasses can one girl eat, really?), then I’ll take a supplement, but I really try to get it through foods.
The Vegetarian Resource Guide has a bunch of info on calcium intake, including sources in a vegan diet and notes on how some calcium-rich foods also contain oxalic acid, which reduces absorption.
A little extra work now sure does beat a shattered hip later.