As evidence continues to grow on the adverse health impacts of ultra-processed foods, researchers are looking at how the risks of specific diseases, including certain cancers, may be influenced by the consumption of these foods. Because diet is known to be a modifiable risk factor for many cancers, gaining a better understanding of which foods to limit and which ones to make the basis of a healthy diet may help people reduce their risk of developing disease.
What are ultra-processed foods?
There’s a difference between processed foods and ultra-processed foods. “Processed food” is a broader label and may apply to both healthy and unhealthy foods. For example, frozen berries and rolled oats are technically processed foods because they have to undergo a degree of processing (in these cases, freezing and steaming and rolling, respectively) to become the form in which they are consumed. You might also refer to these as “minimally processed whole foods.”
Ultra-processed foods generally have a lot of ingredients compared to the one to three ingredients you’ll find in minimally processed foods. This may include added sugar or other sweeteners, unhealthy fats (especially refined oils or hydrogenated fats), and sodium, as well as possible additives like preservatives, emulsifiers, dyes, and starches. These foods are generally highly palatable and low in nutritional value.
Ultra-processed foods and colorectal cancer risk
In a 2022 study by Hang and colleagues published in the Journal of the National Cancer Institute, researchers used data from the Nurses’ Health Study, Nurses’ Health Study II, and Health Professionals Follow-up Study to assess whether consumption of ultra-processed food -- including processed breads, sweets, ready-to-eat meals, savory snacks, beverages, and condiments -- influences risk of colorectal cancer by looking at possible connections between intake of these foods and risk of colorectal cancer precursors, conventional adenomas and serrated lesions. In total, they used data from 142, 052 participants who had undergone at least one lower gastrointestinal endoscopy during the follow-up period of the study.
They noted 11 ,644 patients with conventional adenomas and 10 ,478 with serrated lesions during 18 to 20 years of follow-up. When compared with participants with the lowest ultra processed food consumption, those with the highest had an 11% to 26% increased risk of conventional adenomas and a 13% to 28% increased risk of serrated lesions. Similar results were found for high-risk polyps, with a 7% to 28% increase in risk. Even after adjusting for factors such as body mass index and individual dietary factors such as intake of folate, calcium, vitamin D, and processed meat, these results remained statistically significant.
Researchers stated that these results reflected a link between high consumption of ultra-processed foods and increased risk or precursors to colorectal cancer and that further research will show more about which aspects of these foods may be contributing the most to disease risk. For example, some potential mechanisms at play may be related to their poor nutritional value (such as low fiber and low vitamin and mineral content), high total or saturated fat content, high sugar, or high sodium content. Or perhaps it could be related to the sweeteners and emulsifiers that can disrupt the gut microbiome and contribute to inflammations? Or what about potential carcinogens like acrylamide produced during the heat processing of certain foods or additives like sodium nitrate in processed meats or titanium dioxide used to whiten products that have been linked to carcinogenicity in in vivo and in vitro studies? Further studies could shed more light on this topic.
How To Reduce Disease Risk:
Because diet is a modifiable risk factor for cancer and other diseases, in addition to limiting foods, like ultra-processed foods, known to contribute to increased disease risk, make a point of including plenty of foods that have been shown to have protective effects.
A wide body of research has highlighted the benefits of a Mediterranean-style eating pattern rich in fish, legumes, whole grains, and polyphenol-rich foods like fruits, vegetables, and extra-virgin olive oil. Olive oil, specifically, has been linked to decreased risk of many health issues, including heart disease, cognitive decline, and certain cancers. Include it in everyday cooking and meal preparation to add flavor, enjoyment, and support an overall healthy lifestyle.
