Highly Processed Foods & Cancer Risk

A study out Wednesday suggests eating a lot of highly processed foods might be associated with higher rates of cancer. The study appears in BMJ, and the authors admit more study is needed, but warn that the rapid adoption of what they call “ultra-processed foods” may increase the cancer burden in the coming decades.

We asked Marji McCullough, SCD, RD, strategic director of nutritional epidemiology for her thoughts on the study.

“This was a well-conducted study but we should be cautious about interpreting what exactly is responsible for the higher cancer risk.  For example, people eating more highly processed foods are eating fewer healthy foods that may reduce the risk of cancer.

“Highly processed foods are frequently packed with sugar, salt, fat and calories. The authors did try to control for these factors, but it’s difficult to totally control for these and other dietary components.

“Of note, a large proportion of the highly processed foods in this study were sugary products and beverages, which contribute to weight gain and add little nutritional value to the diet.

“In addition, people who eat more highly processed foods tend to have other unhealthy dietary and lifestyle behaviors which might not have been fully accounted for in this study.

“We know people who eat more processed and red meat, potatoes, refined grains, and sugar sweetened beverages and foods are at a higher risk of developing certain cancers. It’s still unclear what role processing has in this relationship; more research on this will be done to more carefully tease out this risk.

“In the meantime, this is one more piece of evidence that a diet rich in whole grains, whole fruits and vegetables, as recommended in the American Cancer Society guidelines, is beneficial for lowering cancer risk.”

Marji also had an important tip for shoppers: “Focus your shopping on the perimeter of the grocery store,” she says. “That’s usually where the whole foods tend to be; vegetables, fruit, whole grains, etc.”