I got this info from the following Web site. If bran is interfering with the absorbtion of calcium, does that mean that more calcium is leaving the body (and firming up D) or that it's not doing anything? What do you think? http://www.phys.com/b_nutrition/03encyclop.../c/calcium.html Precautions: A high-PROTEIN diet can accelerate calcium loss, as can too much SODIUM or CAFFEINE, postmenopausal hormone changes, lack of exercise and certain steroids. Fiber interferes with the absorption of calcium (particularly bean, nut, wheat BRAN or seed fiber). And OXALIC ACID, present in spinach, Swiss chard, rhubarb, almonds and chocolate, combines with calcium to form calcium oxalate, a chemical SALT the body can't use. On the other hand, too much calcium blocks the absorption of IRON and ZINC.