Vitamin C is a water-soluble vitamin that many animals make, but humans must get from food or vitamin supplements. Vitamin C intake helps prevent scurvy and may help shorten illnesses, such as the common cold and flu viruses. Collagen is also made using vitamin C and is necessary for strength of blood vessels, bones, ligaments and tendons. There is controversy within the medical community regarding safe and effective doses of vitamin C. Mega doses of vitamin C are thought by some to dramatically decrease illnesses. Taking more than the recommended dose of vitamin C per day may be considered excessive
Recommended Limits
The recommended daily limit of vitamin C is 2,000 mg per day for adults. Vitamin C is naturally in some foods, such as citrus fruits like oranges. It is also in other fruits, such as strawberries, watermelon and blueberries. Vegetables including broccoli, spinach, tomatoes and cabbage also contain vitamin C. If you include plenty of fresh fruits and vegetables in your diet, you may consume the recommended amount of vitamin C from your food without taking a supplement. In these situations, taking a vitamin C supplement may push you over the upper limit.
Mega Doses
Robert F. Cathcart, M.D. explained in the "Journal of Orthomolecular Medicine" in 1993 that vitamin C isn't well absorbed in the digestive tract. Illness can increase the body's ability to absorb vitamin C, therefore higher levels are tolerated more easily, noted Cathcart. Vitamin C acts as an antioxidant within the body, neutralizing free radicals and helping prevent their damage on the body. For this reason, Cathcart recommended patients sometimes take as much as 200 g of vitamin C in a 24-hour period when illness occurs. In these cases, vitamin C may be given several times an hour for the first 24 hours or so of the illness.
Reasons for Use
Larger than normal doses of vitamin C may offer health benefits, though more research is needed in most cases. In Cathcart's experience, many conditions were effectively treated from the cold or flu to mononucleosis and chronic fatigue syndrome. The effectiveness and safety of vitamin C at these mega doses has not been proven by the medical community. The Linus Pauling Institute also notes that ongoing clinical trials are evaluating the effectiveness of large doses of vitamin C in cancer treatment and prevention.
Warning
Excessive use of vitamin C may cause side effects in some individuals. The most common side effect is diarrhea. Unabsorbed ascorbic acid pulls water into the bowels, causing loose stools or diarrhea. Other side effects include nausea, vomiting, stomach cramping and kidney stones. Additionally, "The New York Times" reports researchers at the University of Leicester believe that excessive doses of vitamin C could result in damage to the DNA and may cause iron stores within the body to convert to a harmful form of iron that may damage some internal organs. Further research is needed to determine the safety and effectiveness of excessive use of vitamin C. Talk to your doctor or health care provider before taking high doses of vitamin C.
References
- MayoClinic.com; Too Much Vitamin C: Harmful?; Katherine Zeratsky; March 2010
- DoctorYourself.com: The Third Face of Vitamin C; Robert F. Cathcart, M.D.; 1994
- Linus Pauling Institute; Vitamin C; Jane Higdon; January 2006
- "The New York Times"; LS Taking Too Much Vitamin C Can Be Dangerous, Study Finds; Jane E. Brody; April 1998
Member Comments