Vitamin C (Ascorbic Acid)

Your body does not store vitamin C so you must consume enough each day to maintain good health. Vitamin C is needed for the growth and repair of tissues in all parts of your body. It is necessary to form collagen, an important protein used to make skin, scar tissue, tendons, ligaments, and blood vessels. Because of this, your body uses a lot of vitamin C to repair wounds. Vitamin C is also needed to form and repair cartilage, bones, and teeth. Large amounts of vitamin C are used by your body during any kind of healing process, whether it's from a cold, infection, disease, injury, or surgery. In these cases you may need extra vitamin C. Vitamin C helps reduce the damage to the body caused by toxic chemicals and pollutants like drugs and cigarette smoke. Smokers especially need extra vitamin C. Research has shown that vitamin C can help prevent cancer and is necessary for a healthy immune system. It also helps maintain good vision as you get older.

Uses

Vitamin C can have many positive effects on your body, including the following.

• Boosts immune system functions
• Protects against cancer
• Necessary for wound healing
• Helps prevent cataracts
• Increases HDL (good) cholesterol
• Decreases risk of heart disease
• Reduces blood pressure
• Useful in treating allergies
• Maintains healthy blood vessels
• Counteracts asthma spasms
• Helps overcome male infertility
• Helps protect diabetics against long-term complications
• Protects against sunburn and its effects.
• Can assist treatment of bleeding gums, easy bruising, and arthritis
• Assists treatment of arthritis and other inflammatory conditions

If you eat many cured, processed, or preserved meats like bacon, sausage, ham, hot dogs, or sliced luncheon meat, you should know that Vitamin C helps prevent these foods from forming cancer-causing "nitrosamines" in the stomach. It's a good idea to eat foods rich in vitamin C, or take vitamin C supplements, at the same time you eat processed meats.

Dietary Sources

Vitamin C is present in many fruits and vegetables. Foods that are excellent sources of vitamin C include orange juice, green peppers, watermelon, papaya, grapefruit, cantaloupe, strawberries, mango, broccoli, tomato juice, brussels sprouts, cauliflower, and cabbage. Vitamin C is also found in raw and cooked leafy greens (turnip greens, spinach), canned and fresh tomatoes, potatoes, winter squash, raspberries, and pineapple. Vitamin C is sensitive to light, air, and heat. Eating vegetables raw, or minimally cooked, increases their vitamin C content.

Other Forms

You can purchase either natural or synthetic vitamin C, also called ascorbic acid, in a wide variety of supplement forms. Tablets, capsules, and chewable tablets are probably the most popular, but vitamin C also comes in powdered crystalline, effervescent tablet and liquid form. You can purchase dosages ranging from 25 mg to 1,000 mg per tablet. "Buffered" vitamin C is available if you find that regular ascorbic acid bothers your stomach. "Ester-C" is a form of vitamin C which the manufacturer claims is better absorbed by the body. Laboratory testing concluded that this claim is not true, and has shown that regular vitamin C is absorbed just as well.

How to Take It

Vitamin C is not stored in the body, so it must be replaced as it gets used. The best way to take supplements is with meals two or three times per day, depending on the dosage. The Recommended Daily Allowance (RDA) of vitamin C is 60 mg for adults, 70 mg for pregnant women, 95 mg for breast-feeding women, 100 mg for smokers, 40 mg for young children, and 50 mg for older children. Some studies suggest that adults should take between 250 mg and 500 mg twice a day for maximum benefit. Be sure to check with your health care provider before taking more than 1,000 mg of vitamin C on a daily basis.

Precautions

Vitamin C is generally non-toxic. In high doses (more than 2,000 mg daily) it can cause diarrhea, gas, or stomach upset. Check with your health care provider before taking vitamin C supplements if you have any kidney problems. Infants born to mothers taking 6 g or more of vitamin C may develop rebound scurvy due to sudden drop in daily intake.

Possible Interactions

High doses of vitamin C (equal to or greater than 500 mg per day) may raise the levels of aspirin and other acidic medications.

Birth control medications may interfere with the body's ability to use vitamin C.

Cyclosporine, a medication used for the treatment of cancer, may reduce blood levels of vitamin C.

Supporting Research

Adhirai M, Selvam R. Effect of cyclosporin on liver antioxidants and the protective role of vitamin E in hyperoxaluria in rats. J Pharm Pharmacol. 1998;50(5):501-505.

Cohen H, Neuman I, Nahum H. Blocking effect of Vitamin C in exercise-induced asthma. Arch Pediatr Adolesc Med. 1997;151:367–370.

Eades MD. The Doctor's Complete Guide to Vitamins and Minerals. New York, NY: Dell Publishing; 1994.

Eberlein-Konig B, Placzek M, Przybilla B. Protective effect against sunburn of combined systemic ascorbic acid (vit.C) and D-alpha-tocopherol (vit.E). J Am Acad Dermatol. 1998;38:45–48.

Galley HF, Thornton J, et al. Combination oral antioxidant supplementation reduces blood pressure. Clin Sci. 1997;92:361–365.

Hendler SS. The Doctors' Vitamin and Mineral Encyclopedia. New York, NY: Fireside Press, 1991.

Lieberman S, Bruning N. The Real Vitamin & Mineral Book. 2nd ed. New York, NY: Avery Publishing Group; 1997.

Mahan K, Arlin M, eds. Krause's Food, Nutrition and Diet Therapy. 8th ed. Philadelphia, Pa: WB Saunders Company; 1992.

Matsui MS, Rozovksi SJ. Drug-nutrient interaction. Clin Ther. 1982;4(6):423-440.

Mosca L, et al. Antioxidant nutrient supplementation reduces the susceptibility of low density lipoprotein to oxidation in patients with coronary artery disease. J Am Coll Cardiol. 1997;30:392–399.

Murray MT. Encyclopedia of Nutritional Supplements. Rocklin, Calif: Prima Publishing; 1996.

Schumann K. Interactions between drugs and vitamins at advanced age. Int J Vitam Nutr Res. 1999;69(3):173-178.

Watanabe H, Kakihana M, Ohtusuka S, Sugishita Y. Randomized, double blind, placebo-controlled study of ascorbate on the preventive effect of nitrate tolerance in patients with congestive heart failure. Circulation. 1998;97:886–891.

Whitney E,Cataldo C, Rolfes S. Understanding Normal and Clinical Nutrition. St. Paul, Minn: West Publishing Company; 1987.

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The publisher does not accept any responsibility for the accuracy of the information or the consequences arising from the application, use, or misuse of any of the information contained herein, including any injury and/or damage to any person or property as a matter of product liability, negligence, or otherwise. No warranty, expressed or implied, is made in regard to the contents of this material. No claims or endorsements are made for any drugs or compounds currently marketed or in investigative use. This material is not intended as a guide to self-medication. The reader is advised to discuss the information provided here with a doctor, pharmacist, nurse, or other authorized healthcare practitioner and to check product information (including package inserts) regarding dosage, precautions, warnings, interactions, and contraindications before administering any drug, herb, or supplement discussed herein.