Kidney Stones & Vitamin C's Unfortunate Bum Wrap & Why Vitamin C Is a Urinary Tract Infection's worst enemy!


Copyright C 2019, 2008, 2005 and prior years Andrew W. Saul excerpted from, copyright 2008, 2005 and prior years Andrew W. Saul. We value his highly researched knowledge.

First off, here's the executive summary: vitamin C does not cause kidney stones. In fact, vitamin C increases urine flow, favorably lowers urine pH, and prevents calcium from binding with urinary oxalate. More on this below. 

There are five types of kidney stones: 

  1. Calcium phosphate stones are common and will dissolve in urine acidified by ascorbic acid vitamin C. 
  2. Calcium oxalate stones are even more common but they do not dissolve in acid urine. More on them below.  
  3. Magnesium ammonium phosphate (struvite stones) are much less common, often appearing after an infection.  They dissolve in vitamin C acidified urine. 
  4. Uric acid stones result from a problem metabolizing purines (the chemical base of adenine, xanthine, theobromine [in chocolate] and uric acid). They may form in a condition such as gout. 
  5. Cystine stones result from a hereditary inability to reabsorb cystine. Most children's stones are this type, and these are rare. 

The Role of Vitamin C in Preventing and Dissolving Kidney Stones: 

The very common calcium phosphate stone can only exist in a urinary tract that is not acidic. Ascorbic acid (vitamin C's most common form) acidifies the urine, thereby dissolving phosphate stones and preventing their formation.

Acidic urine will also dissolve magnesium ammonium phosphate stones, which would otherwise require surgical removal. These are the same struvite stones associated with urinary tract infections. Both the infection and the stone are easily cured with vitamin C in large doses. BOTH are virtually 100% preventable with daily consumption of much-greater-than-RDA amounts of ascorbic acid. Think grams, not milligrams! A gorilla gets about 4,000 mg of vitamin C a day in its natural diet. The US RDA for humans is only 60 mg. Someone is wrong, and I don't think it's the gorillas. 

The common calcium oxalate stone can form in an acidic urine whether one takes vitamin C or not. However, if a person gets adequate quantities of B-complex vitamins and magnesium, this type of stone does not form. Any common B-complex supplement twice daily, plus about 400 milligrams of magnesium, is usually adequate. 

Ascorbate (the active ion in vitamin C) does increase the body's production of oxalate. Yet, in practice, vitamin C does not increase oxalate stone formation.  Drs. Emanuel Cheraskin, Marshall Ringsdorf, Jr. and Emily Sisley explain in The Vitamin C Connection (1983) that acidic urine or slightly acidic urine reduces the UNION of calcium and oxalate, reducing the possibility of stones. "Vitamin C in the urine tends to bind calcium and decrease its free form. This means less chance of calcium's separating out as calcium oxalate (stones)." (page 213) Also, the diuretic effect of vitamin C reduces the static conditions necessary for stone formation in general. Fast moving rivers deposit little silt. 

Furthermore, you can avoid excessive oxalates by not eating (much) rhubarb, spinach, or chocolate. If a doctor thinks that a person is especially prone to forming oxalate stones, that person should read the suggestions below before abandoning the benefits of vitamin C.  


Robert F. Cathcart II, M.D. writes on “Why Don’t Massive Doses of Ascorbate Produce Kidney Stones?”

“Years ago when Linus Pauling wrote his book "Vitamin C and the Common Cold", the critics immediately labeled the taking of large doses of vitamin C dangerous because it would produce calcium oxalate kidney stones. This practice of telling people that vitamin C caused kidney stones continues today by the critics of vitamin C despite the lack of clinical evidence of kidney stones in people taking vitamin C.


“It was hypothesized that since a significant percentage of ascorbate was metabolized into and excreted as oxalic acid that this oxalic acid should combine with calcium in the urine and deposit as calcium oxalate kidney stones. It is true that those of us who take large doses of ascorbate have elevated oxalic acid in our urine but no kidney stones. With the millions of people in the world taking vitamin C, if vitamin C caused kidney stones there would have been a massive epidemic of kidney stones noticed by this time. There has been none.


“I started using vitamin C in massive doses in-patients in 1969. By the time I read that ascorbate should cause kidney stones, I had clinical evidence that it did not cause kidney stones, so I continued prescribing massive doses to patients. To this day (2006) I estimate that I have put 25,000 patients on massive doses of vitamin C and none have developed kidney stones. Two patients who had dropped their doses to 500 mg a day developed calcium oxalate kidney stones. I raised their doses back up to the more massive doses and added magnesium and B6 to their program and no more kidney stones. I think that the low doses had no effect and they, by coincidence, developed the kidney stones because they were not taking enough vitamin C.”

(If you want to read more by Dr. Cathcart, a quick website search for “Cathcart” from the main page will bring up a lot for you to look at.)

 Ways for ANYONE to reduce the risk of kidney stones: 

  1. Maximize fluid intake. Especially drink fruit and vegetable juices. Orange, grape and   carrot juices are high in citrates which inhibit both a build up of uric acid and also stop calcium salts from forming. (Carper, J. "Orange Juice May Prevent Kidney Stones," Lancaster Intelligencer-Journal, Jan 5, 1994) 
  2. Control urine pH. Acidic urine helps prevent urinary tract infections, dissolves both phosphate and struvite stones, and will not cause oxalate stones. 
  3. Eat your veggies: studies have shown that dietary oxalate is generally not a significant factor in stone formation. I would go easy on rhubarb and spinach, however. 
  4. Most kidney stones are compounds of calcium and most Americans are calcium deficient. Instead of lowering calcium intake, reduce excess dietary phosphorous by avoiding carbonated soft drinks, especially colas. Soft drinks contain excessive quantities of phosphorous as phosphoric acid.  This is the same acid that has been used by dentists to etch tooth enamel before applying sealant. 
  5. Take a magnesium supplement of AT LEAST the US RDA of 300-350 mg/day (more may be desirable in order to maintain an ideal 1:2 balance of magnesium to calcium) 
  6. Be certain to take a good B-complex vitamin supplement daily, which contains pyridoxine (vitamin B-6).  B-6 deficiency produces kidney stones in experimental animals. In high doses, it is also used medically to treat kidney stones. Remember:

  * B-6 deficiency is very common in humans 

  * B-1 (thiamine) deficiency also is associated with stones (Hagler and Herman, "Oxalate Metabolism, II" American Journal of Clinical Nutrition, 26:8, 882-889, August, 1973) 

  1. Additionally, low calcium may itself CAUSE calcium stones (L. H. Smith, et al, "Medical Evaluation of Urolithiasis"  Urological Clinics of North America 1:2, 241-260, June 1974) 
  2.  For uric acid/purine stones (gout), STOP EATING MEAT! Nutrition tables and textbooks indicate meats as the major dietary purine source.  Naturopathic treatment adds juice fasts and eating sour cherries. Increased vitamin C consumption helps by improving the urinary excretion of uric acid. (Cheraskin, et al, 1983). Use buffered ascorbate "C". 
  3.  Persons with cystine stones (only 1% of all kidney stones) should follow a low methionine diet and use buffered C. 
  4. Kidney stones are associated with high sugar intake, so eat less (or no) added sugar (J. A. Thom, et al "The Influence of Refined Carbohydrate on Urinary Calcium Excretion," British Journal of Urology, 50:7, 459-464, December, 1978) 
  5. Infections can cause conditions that favor stone formation, such as overly concentrated urine (from fever sweating, vomiting or diarrhea).  Practice good preventive health care, and it will pay you back with interest. 


      Gerster H. No contribution of ascorbic acid to renal calcium oxalate stones. Ann Nutr Metab. 1997;41(5):269-82. "Even though a certain part of oxalate in the urine derives from metabolized ascorbic acid (AA), the intake of high doses of vitamin C does not increase the risk of calcium oxalate kidney stones. . . (I)n the large- scale Harvard Prospective Health Professional Follow-Up Study, those groups in the highest quintile of vitamin C intake (greater than 1,500 mg/day) had a lower risk of kidney stones than the groups in the lowest quintiles."

      Revusova V, Zvara V, Karlikova L, Suchanek B. Prognosis of urolithiasis and nephrocalcinosis in hypomagnesemia. Czech Med. 1985;8(4):207-13.

      Kridl J, Zvara V, Revusova V, Gratzlova J, Ondrus B. [Inhibition of calcium oxalate urolithiasis with pyridoxine and magnesium in an experiment] Bratisl Lek Listy. 1984 Jan;81(1):21-8. Slovak.

      Ringsdorf WM Jr, Cheraskin E. Nutritional aspects of urolithiasis. South Med J. 1981 Jan;74(1):41-3, 46. Review.

      Schneider HJ, Hesse A, Berg W, Kirsten J, Nickel H. [Animal-experiment studies on the effect of magnesium and vitamin B 6 on calcium-oxalate nephrolithiasis] Z Urol Nephrol. 1977 Jun;70(6):419-27. German.

      Revusova V, Gratzlova J, Zvara V, Kridl J, Suchanek B, Breza J. The evaluation of some biochemical parameters in pyridoxine-treated calcium oxalate renal stone formers. Urol Int. 1977;32(4):348-52.

      Izashvili NP, Kasabian EV. [Metabolism of vitamin B6, citric and oxalic acids, calcium and magnesium in nephrolithiasis] Urol Nefrol (Mosk). 1973 May-Jun;38(3):9-13. Russian.

      Gershoff SN. Production of urinary calculi in vitamin B6-deficient male, female and castrated male rats. J Nutr. 1970 Jan;100(1):117-22.

      Takasaki E, Shimano E. The urinary excretion of oxalic acid and magnesium in oxalate urolithiasis. Invest Urol. 1967 Nov;5(3):303-12.

      [No authors listed] The effect of magnesium and pyridoxine on formation of calcium oxalate stones in man. Nutr Rev. 1967 Oct;25(10):304-5. Review.

      Gershoff SN, Prien EL. Effect of daily MgO and vitamin B6 administration to patients with recurring calcium oxalate kidney stones. Am J Clin Nutr. 1967 May;20(5):393-9.

      Lyon ES, Borden TA, Ellis JE, Vermeulen CW. Calcium oxalate lithiasis produced by pyridoxine deficiency and inhibition with high magnesium diets. Invest Urol. 1966 Sep;4(2):133-42.

      Cheraskin, Ringsdorf Jr. and Sisley: The Vitamin C Connection, Harper and Row, 1983 

      Pauling, Linus. "Are Kidney Stones Associated with Vitamin C Intake?"  Today's Living, September, 1981 

      Pauling, Linus. "Crystals in the Kidney," Linus Pauling Institute Newsletter, 1:11, Spring, 1981 

      Pauling, Linus. How to Live Longer and Feel Better, Freeman, 1986 

      Copyright C 2019, 2008, 2005 and prior years Andrew W. Saul.

      Andrew Saul is the author of the books FIRE YOUR DOCTOR! How to be Independently Healthy (reader reviews at ) and DOCTOR YOURSELF: Natural Healing that Works. (reviewed at )



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