On a low-calcium diet, people should avoid eating sodium, animal proteins, spinach, rhubarb and nuts, according to the National Kidney and Urologic Diseases Information Clearinghouse. Dairy products are very high in calcium but may not be restricted depending on the underlying cause of the diet.
Low-calcium diets are sometimes prescribed to treat hypercalcemia, a condition in which the calcium level in the blood is too high and forms kidney stones, weakens the bones and interferes with the function of the brain and heart, reports WebMD. Until calcium levels return to normal and the underlying malfunction is treated, sometimes with surgery, high-calcium foods must be avoided, states UpToDate.
Sometimes a low-calcium diet is prescribed to treat kidney stones that form as calcium oxalate and calcium phosphate, reports the National Kidney and Urologic Diseases Information Clearinghouse. The more common of the two, calcium oxalate stones, is caused partially by high calcium excretion, while calcium phosphate stones are caused by high levels of calcium and alkaline urine. Calcium oxalate stones are not affected by dietary calcium but may be worsened by calcium supplements.
Adults are recommended a daily intake of 1,000 to 1,300 milligrams of calcium each day, according to MedlinePlus. Women are at greater risk of developing osteoporosis as they age, so their calcium requirements are slightly higher than men's.