Before antibiotics where discovered, vitamin D was used to treat tuberculous and other respiratory illnesses. There is now renewed interest in researching vitamin D for infectious diseases.

SOURSE AMERICAN JOURNAL OF RESPIRTORY AND CRITICAL CARE MEDICINE JULY 15 2007

In 2006 the US Vitamin D council published a study in the Journal of Epidemiology and Infection suggesting among other things that children who are exposed regularly to sunlight are less likely to catch colds and respiratory infections. A separate 2006 study published in the journal Science suggested that Vitamin D might boost the body’s production of naturally occurring antibiotics

Canadian Cancer Society gives a new supplement recommendations for vitamin D in 2007:

• Adults living in Canada should consider taking 1,000 international units (IU) of vitamin D supplements a day in the fall and winter.
• Adults at higher risk of having vitamin D deficiency should consider taking the 1,000 IU supplement year round.

A study published in the American Journal of Clinical Nutrition showed a reduction in cancer rates among postmenopausal women who took vitamin D combined with calcium compared to a placebo.

The study looked at just under 1,200 postmenopausal women from rural Nebraska.

One group was given 1,400 to 1,500 mg of supplemental calcium plus 1,100 IU of vitamin D3, also called cholecalciferol, the calcium supplement alone, or a placebo.

There were 37 cancers in just over 1,000 women. The woman who took calcium and vitamin D reduced  their cancer to 18 per 1,000 women.

Researchers at the University of California, San Diego, suggested in the March 2007 issue of the American Journal of Preventive Medicine that taking 2,000 IU of vitamin D daily along with 10 to 15 minutes in the sun and a healthy diet could reduce the incidence of colorectal cancer by two-thirds.

It looks like vitamin D seems to produce signalling molecules. The significance is that these signals help cells recognize what kinds of cells they should become or when they should stop proliferating, which may explain the vitamin’s anti-cancer properties, said Reinhold Vieth, a professor of nutritional sciences at the University of Toronto and an expert on the vitamin.