Eating leafy greens, such as spinach, cabbage and broccoli, rich in folate, may help to reduce the risk of colorectal cancer, according to a study.

Folate is a natural form of vitamin B9 and is found in many foods. Good sources include foods such as spinach, cabbage, broccoli, sunflower seeds, wholegrains, pulses like chickpeas, lentils and beans, and fruit, especially citrus fruits like oranges.

Folate is also available as a supplement in the form of folic acid.

The findings by researchers at the Imperial College London suggest that increasing the intake of folate via diet or taking supplements can decrease the risk of colorectal cancer by up to 7 per cent.

"When it comes to bowel cancer, there are a number of things that people can do to reduce their risk, including eating a varied diet rich in wholegrains, vegetables, fruit, and beans which supports the findings from this study," said Dr Konstantinos Tsilidis, Reader in Cancer Epidemiology and Prevention at Imperial.

"The potential protective health benefits of vitamin B9 are demonstrated in this large study. The study also found some promising findings about how folate might be influencing cancer risk, including different genes, but these need further exploration," Tsilidis added.

In the largest study of its kind, published in The American Journal of Clinical Nutrition, researchers analysed data from over 70,000 individuals to identify genetic variants that may modify how dietary folate (vitamin B9), folic acid supplements, and total folate can influence the risk of colorectal cancer (CRC).

In line with previous studies, they found that for people consuming higher levels of dietary folate, the odds of developing CRC (including proximal colon, distal colon, and rectal cancer) were reduced by 7 per cent for every 260 micrograms higher consumption of dietary folate, which corresponds to 65 per cent of the daily recommended amount (400 micrograms).

According to the authors, the findings support the hypothesis that folate may be effective for CRC prevention, even at regular levels of intake that can be achieved through the diet. The study also suggests folate might be influencing cancer risk, including different genes involved in modulating this risk.

However, they stress the need for more research to pinpoint the genes involved and their influence.