What Cancer Survivors Should Know About Processed Foods

On World Cancer Day, investigators are continuing to look for ways cancer survivors can improve long-term health and reduce their risk of complications. A recent study published in Cancer Epidemiology, Biomarkers & Prevention explored whether eating large amounts of ultraprocessed foods after a cancer diagnosis could affect survival outcomes.

Ultraprocessed foods are heavily manufactured products that often contain additives, preservatives, artificial ingredients and refined sugars or fats. Common examples include packaged snacks, sugary cereals, fast food, processed meats, soda and ready-to-eat frozen meals. While these foods can be convenient, they are typically lower in nutrients and fiber compared with whole or minimally processed foods.

“What people eat after a cancer diagnosis may influence survival, but most research in this population has focused only on nutrients, not how processed the food is,” said lead investigator Marialaura Bonaccio, Ph.D., of the Research Unit of Epidemiology and Prevention at IRCCS Neuromed in Pozzilli, Italy. “The substances involved in the industrial processing of foods can interfere with metabolic processes, disrupt gut microbiota and promote inflammation. As a result, even when an ultraprocessed food has a similar calorie content and nutritional composition on paper compared to a minimally processed or ‘natural’ food, it could still have a more harmful effect on the body.”

To better understand how these foods may affect cancer survivors, the team of investigators analyzed data from more than 800 men and women who had previously been diagnosed with cancer. Participants were part of the Moli-sani Study, a long-term health study that tracked diet and health outcomes over many years. On average, participants’ eating habits were evaluated more than eight years after their cancer diagnosis, and they were followed for nearly 15 years to monitor survival outcomes.

Investigators compared participants based on how much ultraprocessed food they consumed. They also evaluated overall diet quality using the Mediterranean Diet Score, which measures how closely someone follows a Mediterranean-style eating pattern rich in vegetables, fruits, whole grains, healthy fats and lean proteins.

The study found that cancer survivors who ate the highest amounts of ultraprocessed foods had a significantly higher risk of death from any cause compared with those who ate the lowest amounts. Specifically, survivors with the highest intake had about a 48% higher risk of dying from any cause and about a 57% higher risk of dying from cancer during the study period.

Importantly, these risks remained even after researchers accounted for overall diet quality. This suggests that high intake of ultraprocessed foods may affect health outcomes independently, even among individuals who otherwise follow relatively healthy eating patterns.

The team also explored possible reasons why ultraprocessed foods may increase health risks. They found that higher levels of inflammation in the body and elevated resting heart rate helped explain part of the link between ultraprocessed foods and higher mortality risk. Chronic inflammation is known to contribute to cancer progression, heart disease and other long-term health conditions, while resting heart rate can reflect overall cardiovascular health.

While this study does not prove that ultraprocessed foods directly cause worse survival outcomes, it highlights a possible connection that may be important for cancer survivors to consider. The findings add to growing evidence that diet plays a meaningful role in long-term health after cancer treatment.

Investigators note that more studies are needed to better understand exactly how ultraprocessed foods affect cancer survival and whether reducing these foods can improve long-term outcomes. However, this study reinforces the idea that lifestyle choices, including diet, can remain important even years after a cancer diagnosis.

“The main message for the public is that overall consumption of ultraprocessed foods matters far more than any individual item,” concluded Bonaccio. “Focusing on the diet as a whole and reducing ultraprocessed foods overall and shifting consumption toward fresh, minimally processed, home-cooked foods is the most meaningful and beneficial approach for health. A practical way to do this is by checking labels: Foods with more than five ingredients, or even only one food additive, are likely to be ultraprocessed.”