Although scientists have long suspected an association between vitamin D deficiency and cancer risk, only now are they presenting models which try to explain how this link may work.

The cancer model proposed by a team from the Moores Cancer Center at the University of California in San Diego relies on a loss of cancer cells’ ability to stick together.

“The first event in cancer is loss of communication among cells due to, among other things, low vitamin D and calcium levels,” says Dr Cedric Garland, professor of family and preventive medicine at the UC San Diego School of Medicine.

“[We] propose that this loss may play a key role in cancer by disrupting the communication between cells that is essential to healthy cell turnover, allowing more aggressive cancer cells to take over,” he adds.

The findings come against the backdrop of studies which have shown the average blood levels of vitamin D appear to have decreased in the U.S. between 1994 and 2004.

Experts believe poor diet, a decline in outdoor physical activities and more successful campaigns to reduce sun exposure may have contributed to this phenomenon.

Vitamin D may also be obtained from dairy products and nutritional supplements.