Although there are some published studies that have suggested that increasing calcium and vitamin D will increase the risk of kidney stones, these studies were not well controlled for either calcium or vitamin D intake and other causes of kidney stone development were not evaluated (75). The major cause for kidney stones is the increased absorption of dietary oxalate that is often present in dark green leafy vegetables including spinach. This is the reason why it has been observed that increasing calcium intake reduces risk of developing kidney stones. However, patients who have a history of kidney stones do need to be cautious about their calcium intake. For patients with kidney stones who are not getting an adequate amount of calcium in their diet and need to take a calcium supplement, I recommend either calcium citrate or calcium citrate malate. The reason is that the citrate and malate will chelate the calcium in the urine decreasing risk of kidney stone development. Treating vitamin D de?ciency and increasing vitamin D intake to raise blood levels of 25(OH)D of >30 and <100 ng/ml will not increase the risk of developing kidney stones unless there is some other underlying calcium or bone metabolic disorder (4).
Chapter 44 / Vitamin D for Cancer Prevention and Survival
Edward D. Gorham, Sharif B. Mohr, Frank C. Garland, and Cedric F. Garland
Most kidney stones in the United States and Canada are due to dehydration (120), combined with underlying conditions such as excessive salt intake and metabolic disorders such as hypocitraturia (121, 122), hyperoxaluria (123), hyperuricosuria (124), and an excessively acid or alkaline urinary pH (120). Risk is particularly high in desert environments, apparently due to dehydration (125). Excellent reviews on risk factors are available (121, 122). Restriction of intake of calcium may paradoxically increase the risk of kidney stones, since oxalate bound in the intestine to calcium is not absorbed and does not appear in the urine (126).
- Overview Kidney Stones and vitamin D
- Vitamin D supplementation and fewer kidney stones – meta-analysis of RCT Sept 2016
- Kidney stone production REDUCED in rats when Vitamin D and Calcium was added – Dec 2013
- Kidney stones independant of vitamin D levels in range 20-100 ng – Oct 2013
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