In January of 2012, Dr. Jacqueline Marcus and colleagues from the University of California at San Francisco reported on a 58-year-old woman who developed high blood calcium on a physiological dose of vitamin D, combined with an excessive dose of calcium.
The patient suffered from multiple sclerosis (MS) and was trying to reduce the number of MS attacks by taking vitamin D. She became dehydrated, lethargic, had abdominal pain, impaired balance, weakness, slurred speech, tremors, and two hours of difficulty speaking and so came to the hospital. She had high blood calcium (14.6) and low magnesium (1.3). She reported that she was taking a 5,000 IU capsule of vitamin D daily, together with a combination vitamin D/calcium tablet. The doctors report that her total vitamin D intake was 5,500 IU/day and her total calcium intake was 2,200 mg/day. She responded well to IV fluids and within several hours was better and claimed to have forgotten all about the episode.
Her 25(OH)D level was 103 ng/ml (method of measurement not reported), her parathyroid hormone was low (indicating no evidence of primary hyperparathyroidism at the time of the episode) and (six weeks after the episode) her 1,25 di-hydroxy-vitamin D was normal, indicating that (six weeks after the episode) she was not suffering from any type of immune malfunction that caused a moderate dose of vitamin D to elevate blood calcium levels.
One of the takeaway messages is that calcium supplementation needs to be rethought. Scientists conducted the research about calcium requirements of 1200 mg/day on mostly vitamin D deficient patients. Vitamin D increases active calcium absorption, so people with adequate vitamin D levels do not need to take doses of calcium required for passive absorption. I suspect few vitamin D sufficient people need more than 500 mg/day of supplementary calcium.
However, I would be happier if Dr. Marcus had taken a few steps to be certain the patient was not exceeding the recommended 5,000 IU/day. MS is a disease that makes people look for help anywhere, including 50,000 IU capsules. How much did her relatives say she was taking? Did someone sit down with this woman who was claiming amnesia and carefully interview her for evidence she was taking extra vitamin D? Her 25(OH)D level of 103 ng/ml is not inconsistent with 50,000 IU/day but is generally inconsistent with what we know of 5,000 IU/day. In fact, this is the first adult that I am aware of who achieved a blood level of 103 ng/ml on 5,000 IU/day.
Furthermore, what was the vitamin D content of the capsules she was taking? It is easy to analyze the vitamin D content of capsules to rule out a manufacturing error, which is not uncommon. Do you remember Mr. Gary Null?