It may not be able to prevent the common cold, but vitamin C is still a vital player, sustaining body tissues, blood vessels, the immune system, and more. Recent research hints at another role, one few would expect: Indirectly, vitamin C might help control weight.
In a 2005 study of more than 19,000 people, researchers at Cambridge University found that subjects with low levels of vitamin C tended to accumulate more abdominal fat.
One theory is that excess fat depletes the body of antioxidants such as vitamin C. Another is that the relationship works the other way -- that a shortfall of vitamin C makes it harder for the body to burn fat and to exercise. In a study published last year, Carol S. Johnston, a nutrition professor at Arizona State University, reported that people low in vitamin C oxidized 25 percent less fat during a treadmill test than those with adequate levels.
When the body has difficulty tapping fat stores for fuel, it seems to tire more easily, Johnston says. She found that a deficiency -- getting 45 milligrams of vitamin C instead of the recommended dietary allowance of 75 to 90 -- corresponded with impaired exercise performance. With the right foods, you'll keep levels of vitamin C -- and energy -- high.