Vitamin C

Is a glass of OJ or vitamin C tablets your go-to when the sniffles come? Loading up on this vitamin was a practice spurred by Linus Pauling in the 1970s, a double Nobel laureate and self-proclaimed champion of vitamin C who promoted daily megadoses (the amount in 12 to 24 oranges) as a way to prevent colds and some chronic diseases.

Vitamin C (ascorbic acid) is a nutrient your body needs to form blood vessels, cartilage, muscle and collagen in bones. Vitamin C is also vital to your body's healing process.

Vitamin C is an antioxidant that helps protect your cells against the effects of free radicals — molecules produced when your body breaks down food or is exposed to tobacco smoke and radiation from the sun, X-rays or other sources. Free radicals might play a role in heart disease, cancer and other diseases. Vitamin C also helps your body absorb and store iron.

Because your body doesn't produce vitamin C, you need to get it from your diet. Vitamin C is found in citrus fruits, berries, potatoes, tomatoes, peppers, cabbage, Brussels sprouts, broccoli and spinach. Vitamin C is also available as an oral supplement, typically in the form of capsules and chewable tablets.

Most people get enough vitamin C from a healthy diet. Vitamin C deficiency is more likely in people who:

1. Smoke or are exposed to secondhand smoking
2. Have certain gastrointestinal conditions or certain types of cancer
3. Have a limited diet that doesn't regularly include fruits and vegetables

Severe vitamin C deficiency can lead to a disease called scurvy, which causes anemia, bleeding gums, bruising and poor wound healing.

If you take vitamin C for its antioxidant properties, keep in mind that the supplement might not offer the same benefits as naturally occurring antioxidants in food.