The objective of the study was to assess whether the consumption of ultra-processed foods and drinks is associated with an increased risk of colorectal, breast, or prostate cancers. The research team conducted a case-control study of 7843 adults living in different Spanish provinces, with half of the participants having a diagnosis of colorectal (1852), breast (1486), or prostate cancers (953), whereas the other half were people with the same characteristics who did not have cancer.
Data were obtained from the multicase-control study MCC-Spain, which was collected using a validated questionnaire designed to evaluate the frequency of consumption of usual food and drink items over a 1-year period. The results were then classified according to the level of processing using the Nova classification, which groups foods and drinks into 4 categories by how much processing they undergo, according to the study.
The researchers concluded that the consumption of ultra-processed foods and beverages is associated with an increased risk of colorectal cancer. Specifically, a 10% increment in the consumption of ultra-processed foods and drinks was found to be associated with an 11% increase in the risk of developing colorectal cancer.
“By the low intake of fiber, fruits, and vegetables, which are known to offer protection against colorectal cancer, among people who eat a lot of ultra-processed foods, but also by the additives and other substances with carcinogenic potential typically used in processed food products,” said study first author and ISGlobal researcher Dora Romaguera in a press release.
In the case of breast cancer, no strong relationship was found, but an association was observed in the group of current and former smokers.
“Smoking is a risk factor for breast cancer, and smoking and certain dietary factors, such as the consumption of ultra-processed foods and beverages, are known to have synergetic effects on cancer development,” Romaguera said in a press release.
Further, no association was found between prostate cancer and a diet high in ultra-processed products. Romaguera added that this finding is not surprising and is consistent with the results of previous studies of dietary factors and prostate cancer risk, in which no link was found.
The results of the study also showed that people with breast and colorectal cancer, but not those with prostate cancer, reported less healthy diets than people without cancer in the control group.
“We found differences in terms of their intake of energy, fiber, energy density and saturated fatty acids,” said joint first study author and ISGlobal researcher Sílvia Fernández in a press release. “Consumption of ultra-processed foods and beverages was higher among colorectal and breast cancer cases than in the controls.”
The food groups that accounted for the largest proportion of ultra-processed food consumption were sugary beverages (35%), sugary products (19%), ready-to-eat foods (16%), and processed meats (12%).
“Ultra-processed foods and drinks in general are not yet classified as carcinogenic because the aim of the [International Agency for Research on Cancer (IARC)] was not to assess the overall risk of an individual’s diet, but rather to focus on specific components that might be dangerous, such as processed meats,” said study coordinator Pilar Amiano in a press release.
Amiano added that in light of the results of the present study and current scientific evidence on the health risks associated with ultra-processed foods and drinks, in particular with respect to cancer, “food and public health policies and the IARC should already be taking food processing into account and discouraging the consumption of ultra-processed products.”
Association found between consumption of ultra-processed foods and drinks and increased colorectal cancer risk. ISGlobal. Published March 23, 2021. Accessed March 25, 2021. https://www.isglobal.org/documents/10179/8761301/NdP_ultraprocesados+y+cancer+Clinical+Nutrition+03+2021+eng.pdf/64366530-fead-40e7-b4d6-7089be6229f8.