Powerhouse vitamin: OK, so it can't cure the common cold, but vitamin C may still be a strong ally in the fight against disease

COLD SEASON ROLLS AROUND and bottles of vitamin C supplements start rolling out the doors of pharmacies across America. Yet while the C/cold cure connection has been etched in our psyches ever since the 1970s, when Linus Pauling first proposed the link, science has shown that loading up on C won't prevent or cure your sniffles. At best, taking vitamin C may shorten a cold by a day.

But don't give up on C completely. Even if it's not the cure for the common cold, there are plenty of other reasons why you should make sure you're getting enough of the nutrient. In fact, vitamin C has been linked to so many health benefits lately that it's begun to enjoy renewed nutrition-star status. Today, C can be found in hundreds of products, ranging from breakfast cereals and teas to juices like apple and grape that aren't naturally rich in the vitamin. You can find C in candy, frozen desserts, caramel corn (caramel corn?), and even skin care cosmetics.

A DISEASE FIGHTER

Vitamin C has some basic jobs in the body. It helps form hemoglobin, the protein in red blood cells, and it aids in iron absorption. It also plays a role in keeping the immune system operating in high gear and helps build collagen, the stabilizing tissue in bone, muscle and skin. As an antioxidant, vitamin C is one of our best defenses against cell-damaging free radicals, too, and this is particularly important for very active people to note: Some research suggests that the stress of exercise bumps up the need for antioxidants.

What's got most people excited about C of late (and caused manufacturers to put their fingers on the fortifying button) is the vitamin's potential to protect against disease--and not just one disease, but several. For instance, Harvard researchers conducting the Nurses' Health Study, a large-scale, ongoing investigation, found that premenopausal women with a family history of breast cancer who consumed 205 mg of C a day (the equivalent of one red pepper) had a 63 percent lower risk of the disease than women who consumed 70 mg a day. Studies have also shown that vitamin C may lower the risk of cancers of the mouth, throat, esophagus, colon and lung. "And it may protect against cancer of the digestive and urinary tract as well," says Jane Higdon, PhD, a researcher at the Linus Pauling Institute at Oregon State University. "Vitamin C has been found to inhibit the formation of carcinogenic N-nitroso compounds, especially in the stomach."

Researchers have also established that low blood levels of C are associated with a higher risk of heart disease and stroke, and, according to studies conducted at the University of California, Berkeley, there also seems to be a link between low C levels and high blood pressure. And the power of C doesn't stop there: In a 10-year Tufts University study, subjects who consumed more than 250 mg of the vitamin daily had an 83 percent lower chance of developing cataracts. Some research also suggests that vitamin C may help increase bone density.

While most of the focus on C has been on what it can do inside the body, there has also been some interest in what it can do on the outside. Some studies have found that vitamin C, when applied topically, helps aged skin feel less rough and stay hydrated, decreasing the appearance of lines and wrinkles. It's been found, too, that topical vitamin C protects against sun damage. "If you use a vitamin C product in combination with a sunscreen, it helps prevent sun damage and repairs sun damage at the same time," says Nia Terezakis, MD, a clinical professor of dermatology at Tulane University School of Medicine in New Orleans. Although there are many over-the-counter products that now contain vitamin C, Terezakis warns that they may not all be effective. "Vitamin C is very unstable and easily degrades," she says. "Unfortunately there's no way to tell if a product will work or not." One that has been shown to be effective, she adds, is Cellex-C skin firming cream, though like many other C preparations, it's expensive (about $90 for the company's core formulation).

HOW MUCH C DO YOU NEED?

In light of all the news about vitamin C, it's not surprising that its reputation has soared. Yet that doesn't mean you should load up on the nutrient. After completing a survey of vitamin C studies, Robert Jacob, PhD, a researcher at the USDA's Western Human Nutrition Research Center at the University of California, Davis, noted that many people who have higher intakes of vitamin C might also have healthier diets overall. In other words, experts don't know for sure whether it's vitamin C alone or vitamin C in combination with other nutrients that protects against disease.

For that reason, most experts recommend getting vitamin C through fruits and vegetables whenever possible. "The vitamin C from supplements is absorbed just as well as the vitamin C from fruits and vegetables, but fruits and vegetables contain numerous other nutrients and phytochemicals, which probably work synergistically to prevent diseases," says Higdon. If you just take a supplement and avoid fruits and vegetables, you will miss out on some of these other beneficial compounds. Look at supplements as insurance.