Men who consume a high amount of ultra-processed foods are 29% more likely to develop colorectal cancer than those who eat smaller quantities, a study has revealed.
Scientists from Harvard University and Tufts University have found that sugar-sweetened drinks and ready-to-eat foods can trigger the development of colorectal cancer in men.
Chief author Lu Wang said: “We started out thinking that colorectal cancer could be the cancer most impacted by diet compared to other cancer types.
“Processed meats, most of which fall into the category of ultra-processed foods, are a strong risk factor for colorectal cancer.”
Wang added: “Ultra-processed foods are also high in added sugars and low in fibre, which contribute to weight gain and obesity, and obesity is an established risk factor for colorectal cancer.”
More than 200,000 adults took part in the study by outlining their food consumption by filling in dietary surveys every four years.
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The findings show that those who consume a high amount of ultra-processed foods are more at risk of developing colorectal cancer, particularly men.
Ultra-processed foods that put men most at risk include ham, bacon, fish cakes, fruit-based beverages, soda and milk-based drinks, the study has reported.
According to the research, some ultra-processed foods are not associated with colorectal cancer, such as yoghurt.
Fellow author Fang Zhang said: “We found an inverse association between ultra-processed dairy foods like yoghurt and colorectal cancer risk among women.
“Foods like yoghurt can counteract the harmful impacts of other types of ultra-processed foods in women.”
Co-author Mingyang Song said: “Further research will need to determine whether there is a true sex difference in the associations, or if null findings in women in this study were merely due to chance or some other uncontrolled confounding factors in women that mitigated the association.”
Food additives contained in some ultra-processed foods affect the composition of the gut microbiota and cause inflammation, making it more likely for colorectal cancer to develop.
Song added: “Cancer takes years or even decades to develop, and from our epidemiological studies, we have shown the potential latency effect – it takes years to see an effect for certain exposure on cancer risk. Because of this lengthy process, it’s important to have long-term exposure to data to better evaluate cancer risk.”
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Prior research has found that children and young people in America tend to eat a high amount of ultra-processed foods.
Zhang said: “Much of the dependence on these foods can come down to factors like food access and convenience.
“Chemically processing foods can aid in extending shelf life, but many processed foods are less healthy than unprocessed alternatives.”
Zhang added: “We need to make consumers aware of the risks associated with consuming unhealthy foods in quantity and make the healthier options easier to choose instead. Long-term change will require a multi-step approach.
“Researchers continue to examine how nutrition-related policies, dietary recommendations, and recipe and formula changes, coupled with other healthy lifestyle habits, can improve overall health and reduce cancer burden.”
Zhang concluded: “It will be important for us to continue to study the link between cancer and diet, as well as the potential interventions to improve outcomes.”
The full set of results can now be accessed in the British Medical Journal.
