Interaction with other chemicals
Potential positive interactions
1. Vitamin D is an important co-factor in the intestinal absorption of calcium, as it increases the number of calcium binding proteins, involved in calcium absorption through the apical membrane of enterocytes in small intestine. It also promotes re-absorption of calcium in the kidneys.
2. Magnesium also plays an important role in calcium absorpsion by bones. Release of calcium from the sarcoplasmic reticulum is inhibited by magnesium. Thus hypomagnesemia results in an increased intracellular calcium level. This inhibits the release of parathyroid hormone, which can result in hypoparathyroidism and hypocalcemia. Furthermore, it makes skeletal and muscle receptors less sensitive to parathyroid hormone.
Potential negative interactions
1. Unesterified long-chain saturated fatty acids, i.e. palmitic acid, have a melting point above body temperature and, with sufficient calcium in the intestinal lumen, form insoluble calcium soaps.
2. Sodium binding to calcium
3. Phytic acid binding to calcium
4. Oxalic acid binding to calcium
5. Cortisol binding to calcium
6. Low pH food and proteins (the latter promotes gastric acid)
