a bottle of vitamin c, much vitamin C

Vitamin C, isolated and named more than 100 years ago, is crucial for good health. Even before it was discovered, vitamin C entered history. A lack of fresh fruits and vegetables on long sea voyages meant sailors were susceptible to scurvy. This sapped their energy and caused pain and shortness of breath. Bleeding gums made it difficult for them to eat the hardtack biscuits that were frequent fare. By the mid-18th century, James Lind of the Royal British Navy had figured out that a ration of citrus juice would prevent scurvy. Although it took decades before the navy implemented his findings, ultimately British sailors were issued lemon or lime juice, earning them the nickname “limeys.” But how much vitamin C do humans need?

How Much Vitamin C Should You Get?

Q. My dad can’t drink any citrus juice because it does not agree with him. He eats green vegetables, but not every day. Could he be low in vitamin C? If so, how much vitamin C should he take in a supplement?

A. The recommended dietary allowance (RDA) for vitamin C (ascorbic acid) is 90 mg for adult men and 75 mg for adult women. Smokers need more. So do women who are pregnant or breast feeding. (Here is the detailed breakdown.)

How Much Vitamin C Is in Your Diet?

According to the CDC, nearly 16 million Americans get too little vitamin C, less than 30 mg a day. Some experts suggest supplementing with 200 to 300 mg a day to be safe. Citrus foods are a wonderful source, but not everyone can tolerate them. Other foods high in vitamin C include bell peppers, kiwifruit, broccoli, strawberries and Brussels sprouts. Cantaloupe, cabbage and cauliflower also provide significant ascorbic acid.

Why You Need Vitamin C:

Vitamin C is critical for the immune system, skin and connective tissue and has anti-cancer activity. Vitamin C also promotes the absorption of nonheme iron from plant foods, and thus helps prevent iron deficiency anemia. The RDA may protect people from deficiency (scurvy) but may not be optimal for good health.

You can read more about unusual uses for vitamin C, such as to calm a cough due to asthma or to protect the stomach from damage caused by aspirin or other NSAIDs. Tell us about your experience using vitamin C supplements.

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  1. Jeff

    I have read everything by Linus Pauling–and many other nutrition pioneers–on vitamin C. The body will get rid of vitamin C if one consumes too much. The *optimal* dose for everyone is different. What medical science gets wrong is that human beings are not “cookie cutter” beings–we’re all different, and may need different amounts of each nutrient for optimal health.

    Bowel tolerance is the concept to keep in mind when finding one’s dose of C. And there is a huge difference between being water soluble and the RDA being wrong–2 different concepts.

    RDAs are the minimum amount necessary to prevent the deficiency disease for the nutrient–in this case, scurvy. It’s only 10 mg so the government puts in what they believe is a reasonable fudge factor. The amounts needed to prevent illnesses, or even cure, are much higher. And even if those factors were’t relevant (and they are), who can say that they aren’t doing an enormous amount of good work in those higher doses on the way to the kidneys?

    I took 18 grams daily for years and felt better and got fewer colds. Vitamin C is cheap and completely non-toxic. The worst thing that will happen if you get too much is some diarrhea that will quickly resolve once its cut back.

  2. dzrlib

    I read Dr. Pauling’s book and have been consuming 2-3 grams (2000-3000 mg) per day ever since. It is essential to take the Vitamin C crystals as the pills degrade overtime. Vitamin C is also extremely effetive against viruses.

  3. Gin
    Albuquerque, N M 87120

    Recently you gave a recipe from Dr Low Dog for a thyme based cough reliever. I had jotted it down not realizing my husband would shortly be coughing, coughing from flu. Middle of the night found me mixing up her formula. Fortunately I had all the ingredients. It worked and hubby has been able to rest the night without coughing.

  4. Marie

    When I stayed within the recommended dose of Vitamin C, I was sick all the time – asthma, frequent bronchitis, strep, and pneumonia – and was on frequent prescriptions that did nothing to alleviate my illnesses. I had read about Linus Pauling taking 10,000 mg or 10 grams of Vitamin C every day so I gradually increased toward that amount over a period of years. Ten grams is now my maintenance level.

    I have gone up to 12 grams when I was ill and didn’t suffer from loose stools until I once went beyond 13 grams. I have returned to 10 grams on a daily basis. I no longer have asthma and have fewer bouts of the other illnesses named above. And I do not take any prescription medications of any kind. I know this is not for everyone but I just seem to be one of those individuals with a larger need for Vitamin C that other people. I have learned to ignore medical professionals that say I am merely urinating it out. That’s for the general public; this is for me.

  5. Sheleen

    I take 9 grams of vitamin C every day. The recommended amounts are WAY too low. Vitamin C cured my dad of a terrible illness when traditional doctors wanted to give him painkillers and muscle relaxers. He said the more he took, the better he felt. At his worst he was taking 15-20 grams a day. Today, you would never know he was sick. I am a firm believer in Vitamin C.

  6. SJ

    Back in my twenties I would get UTIs quite often. My doctor finally suggested I take 500 mg of Vitamin C, B-complex with extra B6 and acidophilus with pectin. I did as he suggested and stopped having the UTIs. It was such a relief.

  7. Linda

    I have been taking 500mg daily *forever* in addition to whatever is in my multi-vitamin.
    Never had any problems with 500mg. I don’t do citrus fruits but I know I need Vit C.

    Only recently did I discover that Multi-Vitamins are totally lacking in too many vitamins :(

  8. Dagny
    Philadelphia, PA

    My first thought in reading your article was, “Good luck finding a Vitamin C supplement in a small dose”. The minimum amount seems to be 500 mg. Why the overkill? I don’t understand this. (Vitamin B-12 is sold in huge doses too, I’ve noticed). I know the general wisdom is that Vitamin C is water soluble and therefore can’t build to toxic levels, but my experience is that it can. I was taking 2000 mg. a day of the time-released kind several years ago and experienced chronic stomach problems which I thought were due to too much magnesium. Now I get the minimum amount in a multi-vitamin and a bit extra from an occasional orange at breakfast or Vitamin C fortified canned fruit. Much better.

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