Certain nutrients in the diet are found to improve the absorption of calcium. Vitamin D protein and ascorbic acid are necessary for the proper absorption of calcium. Lysine lactose and citric are also known to promote calcium absorption.
Vitamin D improves the efficiency of calcium absorption particularly when the concentration of available calcium is low in the intestine. Vitamin D improves absorption of calcium when the need of the body for this mineral is comparatively grater, as in infancy, pregnancy, lactation among children with rickets and adults with osteomalacia. Among normal adults absorption and retention of calcium remains unaffected by the addition of vitamin D to their diets.
The absorption of calcium is influenced by protein. Poor absorption occurs when diet are deficient in protein. Increasing the protein content of a low protein diet improves the absorption of calcium. The amount absorbed is dependent upon the proportions in which calcium and phosphorus are present in the diet. The bone contains calcium and phosphorus roughly in the ratio 2:1 some phosphorus is also present in the soft tissue. Calcium phosphate is required for bone formation. Calcium and phosphorus can be utilized fully if they are present in proper proportion.
Factors of the Diet with calcium Absorption
Plant food such as spinach, root, vegetable, rice and maize contain high amount of oxalic acid and phytin. Calcium combines with them to form oxalates and phytates. These are insoluble and cannot, therefore, be absorbed from the intestine. As such calcium from above sources is not available to the body.
Excess of fat in the diet also reduces the absorption of calcium. Fatty acids form insoluble compound with calcium. A deficiency of copper in the diet reduces the absorption of calcium. Magnesium and calcium are absorbed from the same channel and the two compete with each other for absorption. The presence of large amount of magnesium will interfere with calcium absorption.