Excessive Vitamin C consumption does not cause kidney stones
Linus Pauling was a mentor of mine and a sponsor of the Center for Vitamins and Cancer Research that I co-founded at the University of Colorado Medical School in 1980. He was a great supporter of Vitamin C for all that ails you. There are many recent research papers showing reduction in heart disease, increased longevity, and so forth from taking more than 10 times the government recommended amount of Vitamin C. One of the arguments against taking large amount of Vitamin C was the risk of kidney stones. That debate has been laid to rest by a large study showing no increase in kidney stones from Vitamin C and a significant reduction in kidney stones from increased Vitamin B6.
Your physician will probably never tell you about this so you must fend for yourself. Read the research!
Intake of vitamins B6 and C and the risk of kidney stones in women
Curhan, G. C., Willett, W. C., Speizer, F. E., Stampfer, M. J.
J Am Soc Nephrol 10:4:840-845, Apr 1999
Urinary oxalate is an important determinant of calcium oxalate kidney stone formation. High doses of vitamin B6 may decrease oxalate production, whereas vitamin C can be metabolized to oxalate. This study was conducted to examine the association between the intakes of vitamins B6 and C and risk of kidney stone formation in women. The relation between the intake of vitamins B6 and C and the risk of symptomatic kidney stones were prospectively studied in a cohort of 85,557 women with no history of kidney stones. Semiquantitative food-frequency questionnaires were used to assess vitamin consumption from both foods and supplements. A total of 1078 incident cases of kidney stones was documented during the 14-yr follow-up period. A high intake of vitamin B6 was inversely associated with risk of stone formation. After adjusting for other dietary factors, the relative risk of incident stone formation for women in the highest category of B6 intake (> or =40 mg/d) compared with the lowest category (<3 mg/d) was 0.66 (95% confidence interval, 0.44 to 0.98). In contrast, vitamin C intake was not associated with risk. The multivariate relative risk for women in the highest category of vitamin C intake (> or =1500 mg/d) compared with the lowest category (<250 mg/d) was 1.06 (95% confidence interval, 0.69 to 1.64). Large doses of vitamin B6 may reduce the risk of kidney stone formation in women. Routine restriction of vitamin C to prevent stone formation appears unwarranted.