Simply ingesting calcium, in any quantity, means nothing by itself. As we all know for calcium to be utilized it needs to enter the blood stream. Parathyroid hormone (PTH) and vitamin D regulate calcium balance in the blood. PTH is produced by the parathyroid glands, and most cases of hypercalcemia (an excessive amount of calcium in the blood which can lead to kidney damage as well as bone demineralization) are caused by a dsyfunction of PTH or the parathyroid glands and is unrelated to the amount of calcium ingested.
What this means is that as long as the parathyroid gland and PTH are functioning properly, any excessive calcium ingested is excreted and does not enter the blood stream where it causes problems. It would take huge amounts of calcium continuously ingested over a long period of time to itself cause problems.
Again, primary hypercalcemia is not a significant problem, hypercalcemia secondary to conditions such as cancer or granulomatous disease are the problem.
Excessive vitamin D is a different story. Vitamin D is one of only 4 fat soluable vitamins, and is the most toxic because it causes problems at only 4x its needed dose. The principal direct toxic effects of vitamin D are excessive absorption of calcium from the intestine and resorption of calcium from bone. This results in deposition of calcium and phosphorus in soft tissues all over the body, with particular damage to the heart, blood vessels and kidneys. Too much vitamin D is BAD. One last thing to remember though, this only applies to dietary vitamin d, as vitamin d from uv is synthysized differently, one of the reasons natural sunlight and uvb lights are much better than supplements.
Paul Kemes