Formula Medical Group
Apple Valley, CA
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James Krider, MD


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Nutrition
 
Vitamin C - Ascorbic acid

What is vitamin C?

All vitamins are organic substances found in plants and animals. Vitamin C is a water-soluble vitamin, which means it should be consumed every day or so, since large reserves are not stored in the body. When the intake of vitamin C is greater than the body's needs, the excess is excreted through the urine or perspiration.

Why is vitamin C important to nutrition?

Vitamin C is instrumental in forming collagen, an important structural protein that is found in the skin, tendons, bones, cartilage, and connective tissue. Collagen literally holds the body's cells together. By forming such substances, vitamin C plays a part in making blood vessels stronger, helping broken bones and wounds to heal, and increasing the body's natural resistance to infection.

Good sources of vitamin C

Many fruits and vegetables contain vitamin C. The following are particularly good sources.

  • Oranges, grapefruits, and other citrus fruit.
  • Cantaloupe and other melons.
  • Strawberries.
  • Broccoli.
  • Brussels sprouts.
  • Spinach.
  • Sweet and hot peppers.
  • Collards and other greens.
  • Potatoes.
  • Tomatoes.

Vitamin C also is important in the metabolism of other nutrients. For example, it helps the body absorb iron and, perhaps, calcium. It plays a role in the metabolism of amino acids, the building blocks of protein, and folic acid, one of the B vitamins.

In recent years, there has been considerable controversy over vitamin C. Dr. Linus Pauling, a Nobel laureate in chemistry, contends that, when taken in large doses, vitamin C can prevent the common cold. This claim has not been scientifically

 Many fruits, including pineapples and kiwi, are high in vitamin C.
Many fruits, including pineapples and kiwi, are high in vitamin C.

verified, but proponents of high-dose vitamin C have continued to urge its use for a number of human ills.

How much vitamin C do I need?

The Recommended Dietary Allowance (RDA) for adults and children over the age of 4 is 60 milligrams per day. This estimate contains a wide margin of safety, however, because it is about 6 times what is needed to prevent symptoms of deficiency.

What happens if I don't get enough vitamin C?
People with a deficiency of vitamin C may bruise easily or have bleeding gums. A severe deficiency could lead to a disease called scurvy, which is extremely rare in the United States today. Although it is a good idea to consume citrus fruits or other good sources of vitamin C daily, it takes several months of deprivation before signs of deficiency appear. This is because body tissue builds up enough reserves of vitamin C to see it through periods of short supply.

What happens if I get too much vitamin C?
The body normally disposes of any excess water-soluble vitamins, so overdoses of vitamin C should not be a problem. Taking very high

doses of vitamin C, however, can cause diarrhea and bladder irritation, and may promote formation of kidney or bladder stones.

For some people, high-dose vitamin C can be dangerous. For example, it can precipitate a crisis in people with sickle-cell anemia and worsen diarrhea in AIDS patients.

Should I take vitamin C supplements?
There is no need for a healthy person who consumes even a minimal amount of citrus fruits or other fruits and vegetables to take additional vitamin C. No benefit has been found from taking more than 60 milligrams of vitamin C a day — the amount in 6 ounces of orange juice or a regular serving of many other fruits and vegetables.

Advice about vitamin C

  • Since it is water soluble, vitamin C breaks down quickly. Its full benefits can be lost if foods that are good sources are harvested too early, stored too long or in the wrong way, over­cooked, processed, or cooked in water. Buy fresh foods in small quantities, and cook them as little as possible. Steam or stir-fry rather than boil in water.
  • Frozen foods are more likely to retain vitamin C than foods that have been canned or pasteurized.
  • Check food labels to see what percentage of the RDA for vitamin C is in a particular product.
  • If you do take high doses of vitamin C (more than 1,000 milligrams a day), be sure to drink at least 2 quarts of water daily. This will help prevent bladder irritation and kidney or bladder stones.
Strawberries and tomatoes are good sources of vitamin C.
Strawberries and tomatoes are good sources of vitamin C.
This article was last reviewed December 20, 2005 by Dr. James Krider.
Reproduced in part with permission of Home Health Handbook.


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