Recent scientific research shows that eating ultra-processed foods raises cancer risk, especially for colorectal, ovarian, breast, and brain cancers. Consuming beverages that contain artificial sweeteners or added sugar, or animal-based ultra-processed foods, are particularly strongly associated with developing these types of cancer.
In the last several decades, consumption of ultra-processed foods (UPFs) has soared throughout the world. Today, more than half of the calories Americans eat comes from UPFs. These foods are often high in added sugars, fat, and are highly palatable, which makes them a contributing factor to rising rates of obesity. They are also a contributing factor to other chronic diseases, such as diabetes, heart disease, dementia, and depression.
What is the evidence linking ultra-processed foods and cancer?
Overall cancer
A large-scale prospective cohort study based in Europe examined the data of more than 500,000 people to examine the link between ultra-processed foods and cancer. After adjusting for several factors, including sex, smoking, education, physical activity, height, and diabetes, the results, published in 2023 in the Lancet, showed that “a substitution of 10% of processed foods with an equal amount of minimally processed foods was associated with reduced risk of overall cancer, head and neck cancers, esophageal squamous cell carcinoma, colon cancer, rectal cancer, hepatocellular carcinoma, and postmenopausal breast cancer.” The researchers concluded that “this study suggests that the replacement of processed and ultra-processed foods and drinks with an equal amount of minimally processed foods might reduce the risk of various cancer types.”
In a “groundbreaking” multinational cohort study published in 2023, conducted by researchers at the International Agency for Research on Cancer (IARC) and University of Vienna, researchers examined the data of more than 250,000 people from seven European countries. All participants were free of cancer at baseline and were asked about their food and drink habits. After a median follow-up of 11.2 years, the results, published in the Lancet Regional Health — Europe, showed that a higher consumption of ultra-processed foods was associated with an increased risk of cancer, along with cardiometabolic diseases. “Among UPF subgroups, associations were most notable for animal-based products, and artificially and sugar-sweetened beverages.”
A large-scale prospective analysis published in eClinicalMedicine in 2023 examined data from UK Biobank participants who self-reported the food they ate in 24-hour periods between 2009 and 2012. Foods were categorized in the NOVA system and scientists adjusted for confounding factors, including socioeconomic status, smoking status, physical activity, body mass index, alcohol and total energy intake. The researchers found that, during a median follow-up time of 9.8 years, “15,921 individuals developed cancer and 4,009 cancer-related deaths had occurred. Every 10 percentage points increment in ultra-processed food consumption was associated with an increased incidence of overall, and specifically ovarian cancer. Furthermore, every 10 percentage-point increment in UPF consumption was associated with an increased risk of overall, ovarian, and breast cancer-related mortality.”
Ultra-processed food is associated with a higher risk of overall cancer, along with breast cancer, according to research results from a randomized control trial published in 2018 in the BMJ. Breast cancer, which can occur in both men and women, is a common type of cancer that starts with the development of abnormal cells in the breast tissue. That study included the data of more than 100,000 participants over the age of 18 from the French NutriNet-Santé cohort. The researchers concluded: “In this large prospective study, a 10% increase in the proportion of ultra-processed foods in the diet was associated with a significant increase of greater than 10% in risks of overall and breast cancer.”
In a meta-analysis published in 2023 in the journal Clinical Nutrition, researchers examined the connection between ultra-processed foods and cancer risk by doing a systematic search of prior research on this topic. After examining 11 studies, they found “a 10% increment in the diet’s proportion of UPF was associated with increased risk of overall cancer and breast cancer. In addition, a high intake of UPF was associated with increased risk of colorectal cancer and pancreatic cancer . More modest associations were found for chronic lymphocytic leukemia and central nervous system tumors.”
Colorectal cancer
A prospective cohort study published in the BMJ in 2022 sought to examined the link between ultra-processed foods and colorectal cancer risk in American men and women. The researchers found that, “compared with those in the lowest fifth of ultra-processed food consumption, men in the highest fifth of consumption had a 29% higher risk of developing colorectal cancer, and the positive association was limited to distal colon cancer. These associations remained significant after further adjustment for body mass index or indicators of nutritional quality of the diet.” Interestingly, in this study, the associations of colorectal cancer risk and ultra-processed food consumption was not seen in women.
In research based on three prospective cohort studies published in 2023 in the Journal of the National Cancer Institute, scientists investigated data from more than 142,000 people who underwent at least one lower endoscopy within the 18- to 20-year study period to examine links between ultra-processed food consumption and risk of colorectal cancer. They found that participants who ate the most ultra-processed foods had a higher risk of conventional adenomas, serrated lesions, and high-risk polyps, which are both known precursors to colorectal cancer. The researchers added, “These associations were slightly attenuated but remained statistically significant after further adjusting for body mass index, Western dietary pattern score, or individual dietary factors (fiber, folate, calcium, and vitamin D). The results remained essentially unchanged after excluding processed meat from total UPF intake.” The study authors concluded: “Higher consumption of UPFs is associated with an increased risk of colorectal cancer (CRC) precursors. UPFs might be a modifiable target for early prevention of CRC.”
For a matched case-control study published in the journal Nutrition and Cancer, researchers examined the diets of 71 colorectal cancer patients, along with 142 control patients who had non-neoplastic diseases (diseases that are not caused by cancer cell growth). The researchers found that “intake of UPFs was associated with higher risk of CRC. The association remained constant after adjustment for BMI, income, smoking, type of job, educational level, and physical activity. Results of this study indicate that the intake of UPFs is associated with increased odds of CRC.”
Head and neck cancers
In a mediation analysis published in 2023 in the European Journal of Nutrition, researchers examined the link between ultra-processed foods and the risk of head and neck cancers (HNC) and esophageal adenocarcinoma (OAC), using data from more than 450,000 participants across 10 European countries in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. The researchers found that “a 10% g/d higher consumption of UPFs was associated with an increased risk of HNC and OAC.” The researchers concluded: “We reaffirmed that higher UPF consumption is associated with greater risk of HNC and OAC in EPIC. … Further research is required to investigate other mechanisms that may be at play (if there is indeed any causal effect of UPF consumption on these cancers).”
Journalism
Why is cancer striking earlier? One answer could be a diet of ultra-processed foods, by Devi Sridhar, Guardian, July 25, 2023
Cancer warning as experts reveal new list of foods that increase risk, by Liam James, The Independent, June 5, 2023
Ultraprocessed foods linked to ovarian and other cancer deaths, study finds, by Sandee LaMotte, CNN, Feb. 1, 2023
Ultraprocessed Foods and Cancer: Small Changes May Lower Risk, by Sharon Worcester, Medscape, March 24, 2023
Study finds growing evidence of link between ultraprocessed food and cancer, by Sandee LaMotte, CNN, Nov. 22, 2023
We are producing a series to report on the science behind the health risks of ultra-processed foods. We will post each fact sheet as it becomes ready. Learn more about ultra-processed foods and their health risks at our other fact sheets on cardiovascular disease, dementia, depression, addiction, Type 2 diabetes, all-cause mortality and obesity, along with our fact sheet that offers a general overview of UPFs here. These fact sheets are works in progress and will be updated. Please feel free to email mikaela@usrtk.com with any important research or articles that you feel should be included.
