A dose of vitamin D could add years to your life

Trials involving 57,000 people found that those who took supplements regularly were less likely to die over the six-year period.

Scientists have already shown that a deficiency of vitamin D may be to blame for 600,000 cancer cases each year. Other studies have linked low levels of the vitamin with heart disease and diabetes.

Now it is being credited with reducing the risk of death from any causes.

In the latest research, published today in the Archives of Internal Medicine, results from 57,000 people in 18 separate trials of vitamin D supplements were analysed.

They received varying doses, with an average 528 International Units - about the level in commercial supplements.

Over almost six years, 4,777 participants died, while those who took vitamin D had a 7 per cent lower risk of death than those who did not.

The latest study was carried out by the International Agency for Research on Cancer at Lyon and the European Institute of Oncology in Milan.

They reported: "The intake of ordinary doses of vitamin D supplements seems to be associated with decreases in total mortality rates. Interventions effectively strengthening vitamin D status should result in reduced total mortality."

The vitamin's function is only partly understood but it is known to slow the rate of growth of cancer cells and help the immune system.

It is produced naturally in the body through exposure to sunlight and U.S. researchers last month linked higher cancer rates in northern European countries to lower levels of sunshine.

Pamela Mason from the Health Supplement Information Service said: "This is an exciting study.

"There have been a number of studies showing low blood levels of vitamin D are associated with a higher risk of various diseases.

"This latest research shows a reduction in the risk of death over a substantial timespan among people taking supplements.

"In northern climates many people, including the elderly, are likely to have low blood levels of vitamin D because of lower levels of sun exposure.

"But this research, coming after a wet summer in Britain, demonstrates the effectiveness of taking vitamin D supplements or multivitamins, which contain reasonable amounts of vitamin D."

Supplements are available in two forms, vitamin D2 and vitamin D3. Researchers recommend vitamin D3 because it is more active and effective.

Vitamin D is found in salmon, tuna and other oily fish, and is routinely added to milk.

In the UK, the Food Standards Agency does not recommend a specific daily dose of vitamin D unless you are elderly, pregnant, Asian, get little sun exposure or eat no meat or oily fish, in which case 10mcg is advised.