Vitamin C: The Bottom Line
Every multivitamin on the shelves contains vitamin C. But much information about it is incomplete, misleading or wrong. Because C is one of the most popular vitamins and some great new research has emerged lately, I asked authority Balz Frei, Ph.D., director of the Linus Pauling Institute at Oregon State University, to set the record straight. Here’s the real truth — or latest scientific facts — about vitamin C, according to the world’s expert on this vital vitamin.
What is the most exciting new benefit? Surprisingly, it’s fighting heart disease. Vitamin C combats inflammation in blood vessels and helps stabilize plaque so it doesn’t break off and create blockages. It also relaxes blood vessels, helping prevent high blood pressure, angina (chest pain) and mini-strokes. Several studies suggest that a high level of vitamin C in the blood lowers odds of heart disease by 25% to 60%. A likely effective dose: 200mg to 500mg vitamin C daily.
Can vitamin C cure cancer? Vitamin C-packed fruits and vegetables appear to prevent cancer, but whether vitamin C is responsible is unclear, Frei says. Using large oral doses to treat cancer failed in a large Mayo Clinic study. Frei speculates that infusions of extremely high concentrations of vitamin C, as the late Linus Pauling advocated, still may prove toxic to cancer cells. Some doctors discourage taking vitamin C during chemotherapy, but Frei considers the antioxidant — at least in daily doses up to 500mg — more beneficial than harmful to cancer patients.
Does taking vitamin C cure colds? Popping high doses of vitamin C — 1,000mg or more — after you notice symptoms may cut the severity of a cold and its duration by a few days. But there’s no evidence regular megadoses of vitamin C actually prevent colds. Still, Frei says, “I tell people, if it works for them, go ahead.”
Is Ester-C a superior form of vitamin C? “No,” Frei says. “It’s the most common question I get.” Contrary to ads, your body doesn’t know the difference between costly Ester-C and plain old inexpensive ascorbic acid, a common form of vitamin C. “It’s a marketing gimmick,” he says.
How much vitamin C can your body use? In recent National Institutes of Health studies, cells become “saturated” with vitamin C at daily doses of 200mg to 400mg, indicating that’s the maximum humans can absorb. But the research was conducted on healthy adults ages 25 to 30. Because these people have less need for C’s power, that’s probably not an optimal dose for older people or anyone with infections, chronic inflammatory diseases or cancer, Frei says. A better daily dose to meet the uncertainties of aging: 500mg to 1,000mg.
How safe is vitamin C? “It’s impossible to overdose on vitamin C,” Frei says. Excesses are simply excreted. Also, occasional accusations that vitamin C supplements promote kidney stones, clogged neck arteries or chromosome damage leading to cancer don’t hold up, Frei says. The body doesn’t distinguish between C from pills vs. food, so if the claims were true, fruits and vegetables would harm us — an idea he calls ludicrous.
For vitamin C updates, visit the Linus Pauling Institute’s Web site at lpi.oregonstate.edu. To subscribe to the institute’s free newsletter, click on “Micronutrient Information Center.” Frei cautions that vitamin C is not a magic bullet against all ills. It’s just an essential ingredient of a healthy lifestyle.
This EatSmart column is reprinted from USAWEEKEND Magazine and is copyrighted by Jean Carper. It cannot be reprinted without permission from Jean Carper.