A gradual loss of bone occurs with age. There are indications in the literature that not only
calcium but also
fluoride may play an important role in maintaining the bone mass. In view of the high incidence of
osteoporosis and its complications, and in view of the fact that
fluoride is beneficial for the treatment of
osteoporosis, studies have been carried out in this research unit to determine the retention and excretion of
fluoride both during a normal dietary intake of
fluoride and during
fluoride supplementation. Another problem to be examined was to delineate whether certain substances interfere with the intestinal absorption of
fluoride and of
calcium. One such substance is
aluminum contained in commonly used
antacids. The use of small amounts of
aluminum-containing
antacids increased fecal
fluoride significantly, thereby decreasing the intestinal absorption of
fluoride. In addition, the small doses of
aluminum-containing
antacids also affected the metabolism of
calcium and
phosphorus, the primary effect being complexation of
phosphorus in the intestine leading to
phosphorus depletion. This change in
phosphorus metabolism was associated with an increase of the urinary and fecal
calcium excretion resulting in a negative
calcium balance. The dual effect of
aluminum, namely in causing
calcium loss and inhibition of the intestinal absorption of
fluoride, can result in adverse effects on bone which may contribute to bone loss.