Vitamin C has taken its share of "media hits," but the science clearly shows that it's essential
for health - and that supplements can greatly improve your health.
The controversies surrounding vitamin C began to swirl in the late 1960s, when Nobel laureate Linus Pauling, Ph.D., recommended large amounts to reduce cold and flu symptoms and, several years later, to fight cancer. Despite extreme medical resistance at the time, studies have since confirmed the vitamin's ability to fight both infections and cancer, at least in some people.
The truth is that vitamin C plays a fundamental role in all life on Earth. Plants make the vitamin from simple sugars, and it protects them from sunlight-generated free radicals. Nearly all animals also make their own vitamin C (from glucose, or blood sugar), but humans and a small number of other species do not. The reason is not that we're more advanced biologically. Rather, a key gene involved in vitamin C productions was damaged in our ancestors some 35 million years ago, and we continue to inherit with nonfunctioning gene.
Here's a rundown of some of the recent - and diverse - research on the health benefits of vitamin C.
Colds and Flu
Pauling often recommended that people take 10 grams (10,000 mg) of vitamin C daily to prevent and fight colds. Harri Hemila, Ph.D., a professor at the University of Helsinki, Finland, analyzed 21 vitamin C studies and found that 2-6 grams daily reduced cold symptoms by about one-third.
Recently, two suburban Salt Lake City, Utah, chiropractors, H. Clay Gorton, D.C., and Kelly Jarvis, D.C., reported comparable amounts of vitamin C reduced flu symptoms by 85 percent in a group of 47 students. They asked the students to take 1,000 mg of vitamin C hourly for the first six hours after initial symptoms, and then 1,000 mg three times daily thereafter. Gorton and Jarvis wrote that "23 experienced relief of symptoms with one 6-hour treatment of 1,000 mg of vitamin C per hour, 19 with 2, and 5 with 3 such treatments."
Heart Disease
Vitamin C has multiple actions that can reduce the risk of heart disease. Two recent studies have found that 500 mg daily can significantly reduce blood pressure. In a study 38 people with mild to moderate hypertension, Joseph A. Vita, M.D., of the Boston University School of Medicine, reported that 500 mg daily of vitamin C supplements reduced blood pressure by almost 10 percent in just one month.
A separate study, by Martin D. Fotherby, M.D., of the Glenfield Hospital, Leicester, England, found that 500 mg daily of vitamin C reduced blood pressure by an average of 2 mmHg in 40 elderly men and women after three months. "We cannot exclude the possibility that vitamin C supplements given for a longer duration or at a higher dose would not result in further changes to plasma lipids or blood pressure," Fotherby and his colleagues wrote in the Journal of Hypertension.
Researchers have also discovered that vitamin C (sometimes in combination with vitamin E) can improve "endothelial dysfunction," a risk factor for heart disease characterized by stiff blood vessel and reduced blood flow. Diets high in a combination of saturated fat and refined carbohydrates increase endothelial dysfunction. British researchers determined that 1 gram of vitamin C could improve blood vessel flexibility, and the effect may be enhanced with the addition of vitamin E.
Stroke
Several studies have found that vitamin C can reduce the risk of stroke - and limit brain damage from strokes. In a study of 2,100 Japanese men and women, Tetsuji Yokoyama, M.D., of the Osaka City University Medical School, noted that subjects with the highest blood levels of vitamin C at the beginning of the study, suggestive of long-term vitamin C consumption, had the lowest risk of stroke after age 40. People over age 64 with high vitamin C levels were 41 percent less likely to suffer a stroke compared with those who had the lowest vitamin levels.
A recent study found that the oxidized form of vitamin C - that is, the type formed after fighting free radicals - efficiently enters the brain and is particularly good at minimizing brain damage. In an animal study, researchers at Columbia University, New York City, found that in high doses dehydroascorbic acid, which the body normally makes from vitamin C (and can be converted back to vitamin C), reduced stroke damage by up to 95 percent in laboratory mice. The researchers recommended that dehydroascorbic acid be used as a "drug" in stroke patients.
Cancer
Pauling recommended a minimum of 10 grams of vitamin C daily for cancer patients. He found that the life expectancies of some patients were extended but, also, that terminal patients experienced less pain. Over the past 20 years, Abram Hoffer, M.D., Ph.D., of Victoria, Canada, who collaborated with Pauling, has treated several hundred cancer patients with high doses of vitamin C and other vitamins and minerals. About one-third of his earliest patients, who were considered terminal, lived more than ten years and were, by conventional criteria "cured."
Mark Levine, M.D., Ph.D., of the National Institutes of Health, Bethesda, Maryland, believes that intravenous (IV) vitamin C may be more effective than oral supplements in treating cancer. The reason is that IV vitamin C is much better at raising blood levels.
Life span
Because vitamin C can reduce the risk of heart disease, stroke, and perhaps cancer, it can also extend life span.
In a recent study of almost 20,000 middle-age and elderly people, Kay-Tee Khaw, MBBChir (British medical degrees), of Cambridge University, England, found that people with the highest blood levels of vitamin C were the least likely to die at any given age. For example, Khaw found that men and women consuming about 109-113 mg of vitamin C daily had about half the risk of death compared with people consuming about half that amount.
Skin, Bones and Joints
Vitamin C plays key enzymatic roles in the formation of collagen, one of the key proteins that make up skin and other tissues. In one study, Steven S. Traikovich, D.O., a physician in Phoenix, Ariz., assessed the responses of 19 patients who applied a vitamin C-rich lotion to parts of their face for three months. He reported in Archives of Otolaryngology, Head and Neck Surgery that the areas treated with the lotion had reductions in fine wrinkles and roughness and improvements in skin tone and complexion.
Similarly, vitamin C is required for normal bone mineralization. Elizabeth L. Barrett-Connor, M.D., of the University of California, San Diego, recently reported that middle-age and elderly women taking vitamin C supplements had far greater bone density than women who did not take the supplement. Another study, by Dutch researchers, fund that patients with broken wrists suffered less pain when taking 500 mg of vitamin C daily.
Food versus Supplements
It's important to consume at least five servings of vegetables and fruit daily to obtain a modest intake of vitamin C and other antioxidants through the diet. However, various studies have found that 68-91 percent of Americans do not eat this quantity of vegetables and fruit each day. The situation is so bad that a study of 500 patients at clinics in Phoenix found more than a third to have low blood levels of the vitamin.
Because it's nearly impossible to obtain therapeutic levels of vitamins through the diet, better eating habits and supplements would seem to be the answer. Consider starting with a minimum of 1,000 mg of vitamin C daily, and increasing the dosage if you are stressed by health problems. Stores sell a wide variety of vitamin C products, from simple vitamin C to combinations with synergistic antioxidant flavonoids.
Related Article: The Linus Pauling Institute
Nobel laureate Linus Pauling, Ph.D., widely regarded as the second most important scientist (after Einstein) of the 20th century, founded the institute bearing his name after retiring from Stanford University in the 1960s. The Pauling Institute quickly became an important center for vitamin and molecular biology research.
After Pauling died in 1994 (at the age of 93), the institute moved to Oregon State University, Corvallis. Here, some of the brightest researchers in the world have joined together to study vitamin C, vitamin E, and other antioxidants, and how these nutrients can slow the aging process and reduce the risk of disease. Balz Frie, Ph.D., a highly respected researcher is director of the institute.
Although the Pauling Institute is supported by Oregon State University, it also depends on private tax-deductible charitable contributions. You can find more information about the Institute at http://lpi.orst.edu.
Related Article: Are There Problems with Vitamin C?
Q. Does vitamin C cause DNA damage?
A. Several years ago, British researchers reported that supplemental vitamin C led to breaks in one type of DNA, the molecule that forms genes. After a big brouhaha, the researchers reported (with much less fanfare) that vitamin C prevented a much more serious type of break in DNA. The scientists were impressed with vitamin C's powerful ability to inhibit DNA damage, and noted that it had an overall profound protective effect."
Q. Are vitamin C free radicals dangerous?
A. After quenching a free radical, every antioxidant becomes a weak free radical. This is normal cell biology. As long as there aren't too many of them, free radicals play normal roles in health. However, antioxidants work as a team and restore each other to full strength in what Lester Packer, Ph.D., of the University of California, Berkeley, calls the "antioxidant network." In addition, the oxidized (or free radical form of vitamin C) may limit damage from strokes. (See main story.)
Q. Does vitamin C increase the risk of cardiovascular disease?
A. One recent unpublished study found an association (not a cause and effect) between supplemental vitamin C and increased thickness of the carotid artery, a sign of cardiovascular disease. Balz Frie, Ph.D., director of the Linus Pauling Institute at Oregon State University, Corvallis, points out that more than 50 other studies clearly show vitamin C lowering the risk of cardiovascular disease.
Q, Doesn't too much vitamin C cause diarrhea?
A. Robert Cathcart III, M.D., of Los Altos, Calif., recommends using the "bowel-tolerance" method of determine your optimal vitamin C intake. Cathcart believes that your optimal intake is just under the diarrhea-causing amount of vitamin C. Your tolerance for vitamin C will increase when you're sick. It's best to spread out your daily dose into two to four doses, which increases absorption and reduces the chance of diarrhea.
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The information provided by Jack Challem is strictly educational and not intended as medical
advice. For diagnosis and treatment, consult your physician.