A major new study has revealed a disturbing link between high consumption of ultra-processed foods (UPFs) and the development of pre-cancerous growths in women's bowels. The research suggests those eating the most UPFs face a dramatically increased risk of early-onset adenomas, which can develop into bowel cancer over time.
The Alarming Connection Between Diet and Bowel Health
Published in the prestigious journal JAMA Oncology, the study followed 29,105 American nurses with an average age of 45 from 1991 through 2015. Researchers gathered detailed dietary information through food surveys conducted every four years, creating a comprehensive picture of UPF consumption patterns.
Among the participants, 1,189 cases of early-onset adenomas were identified. These growths, a type of polyp, are not cancerous themselves but represent a significant precursor to bowel cancer. The study was funded by Cancer Grand Challenges, a global research initiative founded by Cancer Research UK and the US National Cancer Institute.
Stark Differences in Consumption and Risk
The findings revealed a startling contrast between high and low consumers of ultra-processed foods. Women with the highest UPF consumption were 45% more likely to develop these early-onset adenomas compared to those with the lowest intake.
The research quantified what these consumption levels actually look like in daily life. Those in the highest consumption group ate approximately 9.9 portions of UPFs each day. Cancer Research UK illustrated that a typical day of this magnitude might include sweetened breakfast cereal, white toast with margarine, a flavoured yoghurt, a pre-packaged sandwich, crisps, a canned soft drink, frozen pizza or chicken nuggets with sauces, followed by ice cream or biscuits in the evening.
In contrast, those with the lowest risk consumed an average of just 3.3 servings of UPFs daily.
Addressing the Rise in Early-Onset Bowel Cancer
This research comes at a critical time, as medical professionals grapple with understanding why bowel cancer cases are increasing among younger adults. According to Cancer Research UK, incidence rates of bowel cancer among people aged 25-49 have surged by 62% since the early 1990s.
Dr Andrew Chan, the study's lead author from Harvard Medical School and Massachusetts General Hospital, explained: "We're seeing more cases of bowel cancer in younger adults, and we still don't understand why. Our research is exploring possible factors such as diet, lack of exercise and disruption to the gut microbiome, which may all play a role."
Dr Chan emphasized that while the study suggests these foods could be linked to higher polyp risk, more research is needed to confirm this connection across larger and more diverse population groups.
Professor Charles Swanton, Cancer Grand Challenges scientific committee chairman and Cancer Research UK's chief clinician, noted the study helps "shed light on how diet and other factors are associated with gut health and changes in the bowel linked to cancer risk."
Fiona Osgun, head of health information at Cancer Research UK, added crucial context: "While this study doesn't directly measure cancer risk, it offers useful insight into how diet might influence early changes in the bowel that sometimes lead to cancer. Our diets are shaped by the world around us, from food prices, marketing and local availability."
She stressed that broader changes are needed – from food policy to public health initiatives – to make healthier diets more accessible for everyone, noting that "our overall diet matters more for cancer risk than any single food type."
The study authors concluded that these data "highlight the important role of UPFs in early-onset colorectal tumorigenesis and support improving dietary quality as a strategy to mitigate the increasing burden of early-onset colorectal cancer."
