Ultraprocessed Foods Tied to Higher Cancer Risk: Mingyang Song, MBBS, ScD

During an interview at the American Association for Cancer Research Annual Meeting 2025, Mingyang Song, MBBS, ScD, associate professor of clinical epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, describes the link between ultraprocessed foods and cancer risk. In contrast, he also highlights specific foods and diets shown to reduce cancer risk.

Song expanded on these insights during his presentation, "Ultra-Processed Foods and Cancer Risk: Epidemiologic Insights," held on Monday.

This transcript has been lightly edited; captions were auto-generated.

Transcript

In your presentation, you explored the link between ultraprocessed foods and cancer risk. Can you summarize what the research currently shows about this association?

Currently, there has been a modest association identified between higher intake of ultraprocessed food and an increased risk of cancer. For specific types of cancer, colorectal cancer showed, so far, the strongest association with ultraprocessed food intake. But still, currently, the literature is very limited, and the data acquired are sparse for other cancers.

What about ultraprocessed foods makes them more strongly associated with cancer risk? Are certain cancers more commonly linked to certain ultraprocessed foods?

There are several reasons why ultraprocessed foods may increase cancer risk. First, compared with unprocessed or minimally processed foods, ultraprocessed foods tend to have poor nutrient profiles, so they tend to have high salt, sugar, energy density, saturated fat, and are very low in fiber and vitamins.

Also, ultraprocessed food contains a variety of additives, including emulsifiers, food colors, sweeteners, and other flavors added during the processing of ultraprocessed food.

Finally, ultraprocessed food may contain potential carcinogens. These carcinogens may be produced during food processing. For example, for processed meat, when the meat is cooked at a high temperature, there can be some potential carcinogens resulting from this process. Some examples include heterocyclic amines, which can be generated during the production of processed meat. These 3 factors can all underlie the potential adverse effect of ultraprocessed food on cancer risk.

In terms of specific ultraprocessed foods, so far, the most convincing evidence is between processed meat and colorectal cancer and sugar-sweetened beverages and liver cancer. For processed meat, evidence has shown that it is associated with a higher risk of colon cancer, and this has also been confirmed by laboratory studies, animal studies.

The International Agency for Research on Cancer has classified processed meat as a group 1 carcinogen. This literally put processed meat in the same category as other well-known carcinogens, such as hepatitis B virus and tobacco smoke.

For sugar-sweetened beverages, several studies have tested the association with cancer. So far, the most striking association is with liver cancer. Compared with people who drink very minimal sugar-sweetened beverages, those who drink a high amount of sugar-sweetened beverages can have a roughly 2-fold higher risk of developing liver cancer.

This association seems to be driven by sugar, which is rich in sugar-sweetened beverages. Artificially sweetened beverages haven't been shown to be associated with liver cancer, suggesting that artificial sweeteners may have quite minimal or neutral effects on cancer.

In contrast, are there any dietary patterns or specific foods that have been shown to reduce cancer risk?

Yes, definitely. Over the past few decades, we have learned a lot about how diet and nutrition may influence cancer risk, and we have identified various foods or nutrients that may be beneficial for cancer. This includes the high intake of fruits, vegetables, whole grains, nuts, and some studies suggest yogurt. We do know that these generally healthy dietary patterns are associated with a lower risk of cancer.

Several professional organizations have published or released their dietary recommendations for cancer prevention. For example, the American Cancer Society, the American Institute for Cancer Research, and the World Cancer Research Fund have all published their own recommendations for dietary recommendations for cancer prevention.

They all highlight the importance of consuming high levels of fruits, vegetables, whole grains, nuts, and reducing the consumption of ultraprocessed food, particularly red and processed meat and sugar-sweetened beverages.