A study was just published with exclamatory headlines warning about vitamin D and calcium raising the risk of kidney stones.  They studied the blood and urine of 163 healthy, postmenopausal women for a year.  Investigators gave the women from 0-4,800 iu of vitamin D and raised their calcium to 1,200 – 1,400 mg/day. 1/3 of the women had high levels of urinary calcium and some had elevated blood levels.

That would seem scary, except it isn’t.  First, no one actually had a kidney stone or other trouble.  More important to me is a much bigger study, involving more than 10 times as many women over a 10-20 times longer time span, also showing no kidney stones and no otherwise unaccounted for calcium elevations on blood work.  That bigger study is my clinical practice.

Maybe this is because I insist that my patients drink enough water.  Dehydration is the major factor leading to kidney stones and calcium is notoriously insoluble.  

It may also be another example of our ignorance about calcium metabolism.  For decades, the standard medical advice for patients who had a common calcium-based kidney stone was to avoid calcium.  Then someone actually did a study instead of just making it all up, and found that low calcium intake was associated with INCREASED risk of kidney stones.  

Another contradictory example can be seen in the disease called hyperparathyroidism.  More common than once thought, people with hyperparathyroidism have high calcium levels which can potentially become lethal.  Many feared that giving these patients vitamin D would make things worse.  Turns out that taking vitamin D does not raise calcium levels in patients with hyperparathyroidism.  In fact, in many of these patients, taking vitamin D lowers calcium and helps the patient otherwise.

Bottom line – get as much calcium as you can from food, use calcium supplements to make up for what you can’t eat, take lots of vitamin D (targeting a blood level over 50) and DRINK enough WATER so that your urine just slightly tints the water in your toilet.

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Michael Carlston, MD is an internationally recognized authority in the integration of conventional and complementary medicine in clinical practice, as well as medical education, research and organizational consulting. Practicing in Santa Rosa, California, Dr. Carlston was voted “Best General Physician In Sonoma County, California” by readers of the Sonoma County Independent newspaper and also named one of the outstanding physicians in the Bay Area by San Francisco Focus Magazine. With 30+ years in private practice, his expertise is in nutrition, homeopathy and sports medicine.

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