A high intravenous dose of vitamin C could one day reduce the size of cancerous tumors in people, new studies say. When tested on mice, intravenous vitamin C produced hydrogen peroxide, which proceeded to reduce cancerous tumors in the mice by 43 percent to 51 percent.

The mice had ovarian, pancreatic and brain cancer. The normal cells remained unharmed by the therapy

Low vitamin D levels is linked with cardiac risks, a new study has found adding to the pre-existing evidence about the "sunshine" vitamin's role in good health.

The study, published in the June 23, 2008 issue of the Archives of Internal Medicine, found that patients with the lowest blood levels of vitamin D were about two times more likely to die from any cause during the next eight years than those with the highest levels. The link with cardio-related deaths was particularly strong in those with low vitamin D levels

With fall approaching the days are growing shorter and cold weather is quickly approaching, many Americans will not be getting the necessary levels of vitamin D in the coming months, a deficiency that could put them at higher risk for such serious illnesses as cancer, diabetes, heart disease, depression and osteoporosis.

Christiane Wert Rivard a registered dietitian says, "Sunshine is a significant source of vitamin D.....The body produces vitamin D when the skin is exposed to direct sunlight. However, as we head into these colder and darker months, it's essential to increase your intake of vitamin D since time spent outside is limited

A new study has linked low levels of vitamin D to poor physical performance in older adults. Researchers at North Carolina's Wake Forest University Baptist Medical Center in Winston-Salem made the discovery. Researchers say that older adults who don't get sufficient vitamin D from their diets or from exposure to the sun could be at risk for both poor physical performance and disability.

So getting enough of the vitamin is important, according to lead author Denise Houston, Ph.D

According to a panel of U.S. experts, some Americans might be taking too many vitamins in a hope to live longer.

However, the panel also stated that some individuals need the supplements. The panel said, "For instance, older women benefit from taking calcium and vitamin D to strengthen their bones, and younger women need to take folic acid to reduce birth defects in any children they may have