Corticosteroid use also may cause hypercalciuria, in these cases I use a low-dose thiazide diuretic first and then give calcium supplements. It will inhibit the absorption of the medication. Calcium can also inhibit iron absorption. If a patient is iron deficient, space the iron and calcium supplements, and switch to calcium citrate. Calcium citrate has been shown to be more easily absorbed in patients with acholorhidria when fasting, although if taken with citrus-containing breakfast, calcium carbonate was well absorbed.
Lactose intolerance is a common problem, especially in elderly persons.
Fortunately, yogurt is well tolerated in these persons and it has been documented to be well absorbed. Dietary factors that affect calcium Dietary protein and caffeine can increase urine loss of calcium, but they do not affect the absorption from the intestines. These effects can be measured and are statistically significant, but becomes clinically significant only at large intakes. Calcium absorption is inhibited to a modest degree by fiber in the diet. Although the calcium content in spinach is high, almost none gets absorbed.