Scientists who studied almost 1,600 patients after surgery for bowel cancer found those with the highest levels of vitamin D have half the risk of dying of the disease compared with those with the lowest levels.
The study is the first to correlate the long-term survival prospects of bowel cancer patients after diagnosis with total blood levels of vitamin D.
Vitamin D, sometimes known as the "sunshine vitamin", is made in the body when the skin is exposed to sunlight and is found in foods such as fish liver oil, eggs and fatty fish such as salmon, herring and mackerel.
It is known to boost the uptake of calcium and bone formation. Some observational studies have also suggested a link between low levels of vitamin D and greater risks of many acute and chronic diseases.
Malcolm Dunlop, of the Medical Research Council Human Genetics Unit at the University of Edinburgh who led the study, said it suggested vitamin D supplements may be worth exploring for bowel cancer patients.
Bowel cancer is the second most common cancer in Europe with around 447,000 new cases diagnosed in 2012, said the charity Cancer Research UK.