The Vitamin C and Kidney Stone Story
In their article, doctors Goodwin and Tangum make the point that MDs have received training informing them that high doses of vitamin C can cause kidney stones.
When the authors looked for hard evidence linking vitamin C to kidney stones, they found the opposite. They cited three studies (which I tracked down and read) and found that there was no association between vitamin C intake and stone formation.3,4,5 Recent investigations have concluded that large amounts of vitamin C cause only trivial increases in urinary oxalate formation, and that these increases are not nearly enough to cause stone formation.6,7,8 A 1996 study found that people who consumed 1,500 mg or more of vitamin C only formed 78 percent of the amount of stones seen in groups whose daily vitamin C intake was below 250 mg.9 It should be noted that their data was not statistically significant for a protective effect of vitamin C intake. However, it certainly does not appear to provoke kidney stone formation.
In a 1993 article about vitamin toxicity, I too advised that high dose vitamin C could cause kidney stones because I accepted statements in nutrition textbooks.10 Curiously, in a very popular nutrition book, I found that 3,000 mg of vitamin C is recommended by the authors for the treatment of kidney stones.11 The authors' rationale is that vitamin C acidifies the urine and that acid urine will block stone formation. What is most ironic is that there is no reference given for this recommendation. Thus, I will not make the same mistake twice and make another recommendation based on a chapter in a book.
- Goodwin J, Tangum M. Battling quackery. Archives of Internal Medicine November 9, 1998;158:2187-2191.
- Alhadeff L, Gualtiers T, Lipton M. The toxic effects of water soluble vitamins. Nutrition Review 1984;42:33-40.
- Cowley D, McWhinney B, et al. Chemical factors important to calcium nephrolithiasis: evidence for impaired hydroxyzarboxylic acid absorption causing hyperoxaluria. Clin Chem 1987;33:243-247.
- Power C, Barker D, et al. Diet and renal stones: a case controlled study. Br J Urol 1984;56:456-459.
- Sellstrom B, Danielson B, et al. Dietary habits in renal stone patients compared with healthy subjects. Br J Urol 1989;63:575-580.
- Wandzilak T, et al. Effects of high dose vitamin C on urinary oxalate levels. J Urol 1994;151(4):834-837.
- Diplock A. Safety of antioxidant vitamins and beta keratine. Am J Clin Nutr 1995;52:1510S-1516S.
- Bendich A, Langseth L. Heath effects of vitamin C supplementation. U Am Coll Nutr 1995;14(2):124-136.
- Curhan G, Willett C, et al. A prospective study of vitamin B-6 and C and the risk of kidney stones in men. J Urol 1996;155:1848-1851.
- Andersen GD. Quick review of vitamin toxicity, part II. Dynamic Chiropractic April 23, 1993;11(9).
- Blach J, Blach T. Prescription for Nutritional Healing. Garden City Park: Avery Publishing Group, New York, 1990.
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