Patrick J. Skerrett

High-dose vitamin C linked to kidney stones in men

File this under “if a little bit is good, a lot isn’t necessarily better:” taking high-dose vitamin C appears to double a man’s risk of developing painful kidney stones.

In an article published yesterday in JAMA Internal Medicine, Swedish researchers detail a connection between kidney stone formation and use of vitamin C supplements among more than 23,000 Swedish men. Over an 11-year period, about 2% of the men developed kidney stones. Those who reported taking vitamin C supplements were twice as likely to have experienced the misery of kidney stones. Use of a standard multivitamin didn’t seem to boost the risk.

The average man needs 90 milligrams (mg) of vitamin C a day; the average woman 75 mg. The vitamin is important for making and repairing connective tissue, skin, and bones. It also helps the body absorb iron. Good food sources include red peppers, papaya, and citrus fruits. Vitamin C supplements can deliver 10 times or more of the daily requirement.

In part because of the tireless but misguided efforts of Nobel laureate Linus Pauling and others, many people believe that extra vitamin C can prevent colds, supercharge the immune system, detoxify the body, protect the heart, fight cancer, and more. To date, though, the evidence doesn’t support claims that extra vitamin C is helpful. Despite that, vitamin C represents the biggest single category of vitamin and mineral sales; Americans bought more than $200 million worth of it last year.

Risk is real, benefits aren’t

The Swedish study isn’t the first to link vitamin C with kidney stones. A similar connection was observed in men by Dr. Gary C. Curhan and colleagues at the Harvard School of Public Health. Curiously, in an almost identical study in women, Curhan’s team didn’t find any association between vitamin C intake and kidney stones.

Kidney stones form for a variety of reasons. Genes matter, as do gender (men get them more than women), weight (obesity boosts the risk), and diet (eating a lot of animal protein, not drinking enough fluids). The most common type of stone is a mixture of calcium and oxalate, a substance found in many foods. Some people break down vitamin C into oxalate, which may explain the connection with kidney stone formation.

Is there enough evidence to warn men, at least, from taking vitamin C supplements? Yes, says Dr. Curhan. “High dose vitamin C supplements should be avoided, particularly if an individual has a history of calcium oxalate stones.”

In a commentary accompanying the vitamin C article, Dr. Robert H. Fletcher, emeritus professor of ambulatory care and prevention at Harvard Medical School, made the point a different way. If there’s truly a cause-effect relationship, then one of every 680 people who take high-dose vitamin C (also known as ascorbic acid) would develop kidney stones. “This is not an insignificant risk,” Fletcher writes. “But more to the point, is any additional risk worthwhile if high-dose ascorbic acid is not effective?”

Comments:

  1. Olufisola Agboola

    If another 11,000 men not vitamin c supplement were studied, would the incidence of kidney stone be 0 or much less than 2%?

  2. Jane

    Firstly rather than vitamin C, people with a predisposition to kidney stones should drink citrus juice in order to tip the intracellular ph toward alkaline. The resulting citric acid efflux, will also remove the calcium that contributes to stone formation.

  3. Mark

    Vitamin C is helpful for human health. We meet this vitamin oranage,lemon and so on. Many people believe that extra vitamin C can prevent colds, supercharge the immune system, detoxify the body, protect the heart, fight cancer, and more. As kidney stones are more because of this calcium oxalate than the intake vitamin C should be controlled.

  4. Houdini

    “In part because of the tireless but misguided efforts of Nobel laureate Linus Pauling and others, many people believe that extra vitamin C can prevent colds, supercharge the immune system, detoxify the body, protect the heart, fight cancer, and more. To date, though, the evidence doesn’t support claims that extra vitamin C is helpful.” Thank you for your opinion. I’m interested as to why you believe Dr. Linus Pauling’s studies were “misguided.” Surely, scholars such as, Dr. Abram Hoffer, Dr. Max Gerson, Dr. Dan Rogers, Professor Ian Brighthope, and Dr. Dean Ornish, to name some, along with myself, would disagree. What about the hundreds of thousands of people who have been cured by Vitamin C? By no means am I saying your findings are incorrect, but essential details are greatly lacking in your claim. For instance, of the 23,000 Swedish men that were involved in this 11-year case study, what records do researchers have of their daily lifestyle, their daily nutrition, and what other vitmans or medications were they taking during this period. This is but one question of hundreds that’s paramount before making a statement to the public about the disadvantages of Vitamin C.

    • Laura Morrison

      My husband is having his 48th kidney stone attack today at the age of 52, please respond further on the nutritional therapy he so needs……………Modern medicine isn’t doing it……….you think!

  5. Stalina Dsouza

    Me and my lab-partner made a mistake in our project. But that’s okay, we have fixed it. Now we want to know what would happen if you would take 15730 miligram of vitamin C on one day. That is the value we found that was in an orange.

  6. Stereo Max

    My goodness to see this blog its a very good and great blog. After reading all about vitamins i realize how it works and how can we maintain our body with vitamins.
    But this health and vitamin blog contains only information for Men he should blog also Women that may be more helpful and beneficiary

  7. Liam Rubel

    Nowadays many are going for citrus fruits more because of weight loss concerns, detoxifying body and also for sugar level control. As kidney stones are more because of this calcium oxalate than the intake vitamin C should be controlled.

  8. Chris Heald

    Why only men? high dose cant effect women?

  9. Jake

    Oh for pete sake, why is everything to do with men? Can scientists work that out? Everybody wants longevity, men included!

  10. Medicare Health Plans

    I already suffer from kidney stones and passed my first one at age 15. It takes a lot of effort to avoid the foods and drinks I am supposed to, but I was told to drink a lot of lemonade (the good stuff). I assume that getting my vitamin C naturally instead of through supplements won’t increase my risk.