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Leafy greens decrease bowel cancer risk

New study shows that eating foods with higher folate levels reduces the risk of colorectal cancer.

Author: The WCRF team
Published: 30 November 2023

Leading cancer prevention and survival charity World Cancer Research Fund has funded a large study which found that higher levels of folate (vitamin B9) and folic acid in the diet can reduce the risk of bowel (colorectal) cancer by 9%.

The charity recommends that people, especially men, should eat more leafy greens, such as spinach, cabbage, broccoli on a daily basis, to reduce their risk of bowel cancer.

The study was led by Dr Konstantinos Tsilidis, Reader in Cancer Epidemiology and Prevention at Imperial College London. The study, published in the American Journal of Clinical Nutrition, gathered data from more than 70,000 people and looked into how food high in folate, such as leafy green vegetables, affects cancer risk.

The research revealed a stronger link in males than in females. If men and women both had the same amount of folate, there was an 11% lower risk of getting bowel cancer for men, compared with 6% for women.

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

It is also sold as a supplement in the form of folic acid. Folate and folic acid are critical for producing red blood cells and are especially important for women who are pregnant or trying to get pregnant.

Bowel cancer is the 3rd most common cancer globally. In the UK, bowel cancer is the 4th most common cancer, with nearly 45,000 people diagnosed every year, and more than 120 new cases diagnosed each day. 1 in 15 men are likely to receive a bowel cancer diagnosis in their lifetime, compared with 1 in 18 women.

There are ways to reduce bowel cancer risk, including eating a varied diet – rich in wholegrains, vegetables, fruit, and beans – which supports the findings from this study.

Dr Tsilidis said:

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

Dr Helen Croker, Assistant Director of Research and Policy at World Cancer Research Fund, said:

Interestingly, in this study, the protective effects were seen at usual dietary intakes of folate, further indicating the importance of folate-rich foods as part of a healthy, balanced diet, as well as being physically active.

Matt Lambert, Nutritionist and Health Information Manager at World Cancer Research Fund, said:

This study adds to what we’ve been saying for years – that a healthy diet based around vegetables, fruit, wholegrains and pulses can help reduce cancer risk. Folate, which is found in a variety of foods, has not only has been linked to a reduced bowel cancer risk, but also supports our overall health if eaten frequently.

We understand that not everyone enjoys eating vegetables, which is why we have lots of delicious and varied recipes that use vegetables without you even knowing they are there.