LOS ANGELES, Aug. 21 (Xinhua) -- Adequate intake of vitamin D may help prevent cancer, according to a new study.

    A number of 600,000 cases a year of breast and colorectal cancer could be prevented each year if vitamin D3 levels met the target proposed by researchers, said the study by researchers at the Moores Cancer Center at the University of California, San Diego (UCSD).

    The effect of Vitamin D3 is more evident in countries north of the equator. Vitamin D3 is available through diet, supplements and exposure of the skin to sunlight.

    "For the first time, we are saying that 600,000 cases of breast and colorectal cancer could be prevented each year worldwide, including nearly 150,000 in the United States alone," said Cedric F.Garland, a cancer prevention specialist at UCSD.

    The paper, which looks at the dose-response relationship between vitamin D and cancer, will be published in the August edition of the journal Nutrition Reviews.

    The study combined data from surveys of serum vitamin D levels during winter from 15 countries. It is the first such study to look at satellite measurements of sunshine and cloud cover in countries where actual blood serum levels of vitamin D3 had also been determined.

    The data were then applied to 177 countries to estimate the average serum level of a vitamin D metabolite of people living there.

    The data revealed an inverse association of serum vitamin D with risk of colorectal and breast cancer.