Ten minutes of sun 'could stop 30,000 cases of cancer', researchers say

Vitamin D, which helps protect against the cancers, is created in the body when it is exposed to sunshine.

The researchers believe vitamin D deficiency may be to blame for 600,000 cancer cases worldwide each year, particularly in northern European countries where sun exposure levels are relatively low.

The study - which comes amid the wettest summer since records began - recommends ten or 15 minutes a day in the sun to maximise vitamin D levels.

There is mounting evidence that vitamin D could play a vital role in helping prevent disease, with the sun helping top up natural levels more effectively than diet.

Although most people in northern Europe are not sufficiently lacking in vitamin D to be classified as deficient, some experts believe blood levels should be higher to optimise health.

In the latest study, scientists at the Moores Cancer Centre at the University of California, San Diego, estimate that 250,000 cases of colorectal cancer and 350,000 cases of breast cancer could be prevented worldwide by increasing the intake of vitamin D3.

In the UK, such a strategy would reduce cancer cases by 30,000 a year.

The study combined data from surveys of blood levels of vitamin D during winter from 15 countries, along with satellite measurements of sunshine and cloud cover.

The data was then applied to 177 countries to estimate the average blood level of vitamin D among inhabitants, says a report in the journal Nutrition Reviews.

The study showed lower levels of vitamin D are linked to higher levels of breast and colon cancers.

Researchers say increasing vitamin D levels has the potential to help prevent cancer.

Dr Cedric Garland, the cancer prevention specialist who led the study, said: "This could be best achieved with a combination of diet, supplements and short intervals - ten or 15 minutes a day - in the sun."

The study says an intake of 50 microgrammes a day of vitamin D3 would lead to a 'meaningful reduction' in the two cancers.

Vitamin D supplements are available in two forms - vitamin D2 and vitamin D3.

The mechanism by which vitamin D works is only partly understood, but it slows the rate of cancer cells' growth.

It is made when the body is exposed to the sun's UVB rays.

These only reach northern countries in summer months because the angle of the sun means they are mostly absorbed in the atmopshere.

The best chance of producing vitamin D is on sunny, summer days because less is made in cloudy conditions.

But Dr Garland said those with a history of skin cancer or a light sensitivity disease such as lupus should avoid sun exposure.

Clothing and a hat should be used when in the sun for longer than 15 minutes.