New research suggests that ultra-processed foods, already known to be detrimental to overall health, may pose a particularly significant risk to cancer survivors. A study published in , in Cancer Epidemiology, Biomarkers &. Prevention, found a strong association between high consumption of these foods and increased risk of both cancer recurrence and all-cause mortality in individuals who have survived a cancer diagnosis.
The Italian researchers followed cancer survivors for , and their findings revealed that those with the highest intake of ultra-processed foods experienced a 59 percent increase in the risk of cancer returning and a 48 percent increase in the risk of death from any cause, compared to those who consumed the least.
While the precise mechanisms underlying this link remain under investigation, the study authors suggest that approximately 37 percent of this association could be explained by elevated levels of inflammatory markers and a faster resting heart rate in those consuming more ultra-processed foods. This suggests a potential pathway through which these foods may negatively impact health outcomes in cancer survivors.
What are Ultra-Processed Foods?
Ultra-processed foods are characterized by their industrial production and the inclusion of ingredients not typically used in home cooking. These include emulsifiers, preservatives, artificial colors, and artificial flavors. This broad category extends beyond obvious examples like soft drinks, instant noodles, and potato chips to include less intuitively recognized items such as flavored yogurts and commercially prepared whole grain breads.
David Labbé, a scientist with the cancer research program at the McGill University Health Centre Research Institute, emphasized the growing body of evidence linking ultra-processed foods to adverse health outcomes. “We knew there was an increased risk of developing cancer linked to ultra-processed foods,” he said. “Now there is evidence that there is an increased risk of dying, either from cancer or other causes.”
Uncertainties and Potential Biases
Despite the compelling findings, researchers acknowledge that several factors require further investigation. Labbé cautioned that the observed association could be influenced by selection bias. “Perhaps patients are in poorer health,” he explained. “That may be why they consume more ultra-processed foods. Perhaps they are people who have had cancer or more aggressive treatment. Perhaps they are no longer able to cook at home with higher quality ingredients.”
The study authors also note that the substances used in industrial food processing can interfere with metabolic processes, disrupt the gut microbiota, and promote inflammation. They highlight that even foods with seemingly comparable calorie content and nutritional profiles to minimally processed alternatives may have a more detrimental effect on the body due to these industrial additives.
Beyond Prevention: Impact on Survivors
The findings underscore the importance of dietary considerations not only for cancer prevention but also for long-term health management among survivors. While preventing cancer remains a crucial goal, Labbé stresses the potential for dietary interventions to improve outcomes after a diagnosis. “We can’t really prevent cancer, but we can reduce the risk of developing it,” he said. “We need to limit our consumption of processed foods high in added sugars, processed meats, sugary soft drinks, etc.”
A Growing Public Health Concern
The prevalence of ultra-processed foods in modern diets is a growing public health concern. According to recent data, these foods account for nearly 45 percent of the daily energy intake of Canadians aged 20 and over. This highlights the widespread exposure to potentially harmful ingredients and the need for greater awareness and dietary changes.
The study utilized the Nova food classification system, which categorizes foods into four groups: minimally processed or unprocessed foods (green category); processed food ingredients (yellow category); processed foods (orange category); and ultra-processed foods (red category). While not widely known in Quebec, studies have demonstrated its effectiveness in promoting weight loss and managing conditions like diabetes.
A Parallel to Tobacco Regulation
Labbé draws a parallel between the growing evidence against ultra-processed foods and the historical response to tobacco. “It’s a bit like cigarettes,” he said. “We didn’t know exactly which chemical compound increased the risk of lung cancer in smokers, but that didn’t stop us from starting to legislate and then adopting regulations and laws to regulate and reduce smoking.” He believes that even without a complete understanding of the mechanisms involved, “there is enough smoke to say that we, as individuals and as a society, should start making choices or supporting people to move away from ultra-processed foods.”
The findings from this study, and others like it, reinforce the importance of prioritizing whole, unprocessed foods in the diet, particularly for individuals navigating the challenges of cancer survivorship. Further research is needed to fully elucidate the complex interplay between ultra-processed foods, inflammation, and long-term health outcomes, but the current evidence strongly suggests a need for caution and a shift towards more mindful eating habits.
