In the largest study to date into the link between diet and bowel cancer, researchers at Oxford Population Health’s Cancer Epidemiology Unit have found that an additional 300mg of calcium each day is associated with a 17% decrease in the risk of colorectal cancers. The study is published in Nature Communications.
Analysis from Cancer Research UK, who funded the study, has shown that there are around 44,000 cases of bowel cancer every year, making it the fourth most common cancer in the UK. Studies suggest that more than half of all cases of bowel cancer are preventable.
Researchers used dietary data from more than 542,000 women who participated in the Million Women Study and looked at their health records over an average of 16 years to investigate the link between 97 food products and nutrients and bowel cancer risk.
The findings showed that foods and drinks rich in calcium such as milk and yoghurt were associated with a lower risk of a bowel cancer diagnosis. Calcium was found to have a similar effect in both dairy and non-dairy sources, suggesting that it was the main factor responsible for cutting risk.
Key findings:
- Food and drinks rich in calcium such as milk and yoghurt were associated with a lower risk of bowel cancer;
- Calcium was found to have a similar effect in both dairy and non-dairy sources, suggesting that it may be the main factor responsible for reducing risk of cancer;
- There was a clear link between alcohol consumption and increased risk of bowel cancer. An additional 20g of alcohol (equivalent to a large glass of wine) was associated with a 15% increased risk of bowel cancer;
- Red and processed meat were among the other foods associated with an increased risk of bowel cancer with 30g more per day linked to an 8% increase in risk.
Dr Keren Papier, Senior Nutritional Epidemiologist at Oxford Population Health and lead author, said ‘This is the most comprehensive single study ever conducted into the relationship between diet and bowel cancer, and it highlights the potential role of calcium in the development of this disease. Further research is needed to understand the potential health impacts of increasing calcium in different populations.’
Sophia Lowes, senior health information manager at Cancer Research UK, said ‘Bowel cancer is one of the most common cancers affecting people in the UK, which is why it’s so vital that we know how to prevent it. Maintaining a healthy, balanced diet, alongside keeping a healthy weight and stopping smoking, is one of the best ways to lower your risk of bowel cancer. This includes cutting down on alcohol and red and processed meat, and eating lots of fruit, vegetables, and wholegrains. Dairy products like milk can also be part of a diet which reduces bowel cancer risk. We look forward to further research, including into the effects of specific ingredients like calcium, to ensure fewer people are impacted by this devastating disease.’
The researchers acknowledge that the study has some limitations such as the population being largely of European descent, so it is not yet known if the results are generalisable to other populations especially those where lactose intolerance is common.