High consumption of ultra-processed foods associated with CRC in men

Among women, only consumption of ready-to-eat or -heat mixed dishes was linked to increased risk of colorectal cancer (CRC), according to a new analysis of the Health Professionals Follow-up Study and Nurses' Health Studies.

Men who eat more ultra-processed foods have higher risk of colorectal cancer (CRC), according to an analysis from the Health Professionals Follow-up Study, and certain of these foods were also associated with risk in women.

Researchers used dietary intake data from 46,341 men in the Health Professionals Follow-up Study and 159,907 women from the Nurses' Health Studies to evaluate associated risk of CRC. No participants had been diagnosed with cancer at baseline. A total of 3,216 cases of CRC (1,294 in men, 1,922 in women) were documented during the 24 to 28 years of follow-up. Results were published by The BMJ on Aug. 31.

Men in the highest fifth of ultra-processed food consumption had significantly higher risk of CRC than those in the lowest fifth (hazard ratio [HR], 1.29 [95% CI, 1.08 to 1.53]; P=0.01). The positive association was seen only with distal colon cancer (HR, 1.72 [ 95% CI, 1.24 to 2.37]; P<0.001), not proximal colon or rectal cancer. The associations remained significant after adjustment for body mass index and nutritional quality of diet. No association was observed between overall ultra-processed food consumption and CRC in women, but there was an association with the subgroup of ready-to-eat or -heat mixed dishes (HR for highest consumption vs. lowest, 1.17 [95% CI, 1.01 to 1.36]; P=0.02). Among men, associations were seen with meat/poultry/seafood-based ready-to-eat products (HR, 1.44 [95% CI, 1.20 to 1.73]; P<0.001) and sugar-sweetened beverages (HR, 1.21 [95% CI, 1.01 to 1.44]; P=0.013). Consumption of yogurt and dairy-based desserts was negatively associated with CRC in women (HR, 0.83; [95% CI, 0.71 to 0.97]; P=0.002).

“This study is among the first that has detected a positive association between ultra-processed food consumption and risk of colorectal cancer among men,” the study authors said. They highlighted the persistence of the association after adjustment for dietary quality and body mass as important, as it suggests that other attributes of the foods might be responsible. “For example, ultra-processed foods commonly contain food additives such as emulsifiers and artificial sweeteners, which may alter gut microbiota, promoting inflammation and colon carcinogenesis,” they wrote.

A complicating factor in this study is that some ultra-processed foods are healthier than others, the authors said. That may explain, for example, why yogurt and dairy-based desserts were actually associated with lower risk among women. The observed associations between ready-to-eat or -heat mixed dishes and CRC “support the recommendation by the World Cancer Research Fund International/American Institute for Cancer Research to limit the intake of ‘fast foods' for the primary prevention of cancer,” the authors said.

An accompanying editorial explained that ultra-processed foods include sodas and other sugary drinks; packaged snacks; commercial breads, cakes, and cookies; candy; sweetened breakfast cereals; margarine; and preprocessed burgers, pastas, and pizzas. The editorial called for “official public policies, including guidelines and publicity advising avoidance, and actions, including statutes, designed to reduce production and consumption of ultra-processed foods and to restrict or preferably prohibit their promotion.”