A combination of high-dose Vitamin D, Omega-3s, and simple home strength exercises can help reduce cancer risk in healthy adults aged 70 or older by 61 per cent, claims a study.

Published in Frontiers in Aging, it is the first study to test the combined benefit of three affordable public health interventions for the prevention of invasive cancers - that has grown past the original tissue or cells where it developed, and spread to otherwise healthy surrounding tissue.

Apart from preventative recommendations such as not smoking and sun protection, public health efforts that focus on cancer prevention are limited, according to Dr Heike Bischoff-Ferrari of the University Hospital Zurich in Switzerland.

"Preventive efforts in middle-aged and older adults today are largely limited to screening and vaccination efforts," Bischoff-Ferrari noted.

Studies have shown that Vitamin D inhibits the growth of cancer cells. 

Similarly, Omega-3 may inhibit the transformation of normal cells into cancer cells, and exercise has been shown to improve immune function and decrease inflammation, which may help in the prevention of cancer.

However, there was a lack of robust clinical studies proving the effectiveness of these three simple interventions, alone or combined.

Bischoff-Ferrari and her colleagues tested the effect of daily high-dose Vitamin D3 (one form of Vitamin D supplements), daily supplemental Omega-3s, and a simple home strength exercise, alone and in combination, on the risk of invasive cancer among adults aged 70 or older.

The three-year trial, held in Switzerland, France, Germany, Austria, and Portugal, involved 2,157 participants.

The results show that all three treatments (Vitamin D3, Omega-3s, and exercise) had cumulative benefits on the risk of invasive cancers, Bischoff-Ferrari said.

Each of the treatments had a small individual benefit but when all three treatments were combined, the benefits became statistically significant, and the researchers saw an overall reduction in cancer risk by 61 per cent.

"Our results, although based on multiple comparisons and requiring replication, may prove to be beneficial for reducing the burden of cancer," Bischoff-Ferrari said, adding the need for further studies.