Ultraprocessed Food and Increased Risk of Cancer: UK Study

Eating ultraprocessed food appears to be associated with an increased risk of cancer overall and with an increased risk of dying from cancer, particularly ovarian cancer, suggest researchers reporting an observational study from the United Kingdom.

The first-of-its-kind study of nearly 200,000 middle-aged adult participants in the UK Biobank database showed that for each 10 percentage point increase in the consumption of ultraprocessed food, there was a 2% increase in the overall incidence of cancer (hazard ratio [HR], 1.02), a 19% increase in ovarian cancer incidence (HR, 1.19), and increased risk of overall, ovarian, and breast cancer–related death (HR, 1.06, 1.30, and 1.16, respectively).

These associations persisted after adjusting for numerous socioeconomic and lifestyle factors, including smoking status, diet, physical activity level, and body mass index.

The study, published online January 31 in eClinicalMedicine, provides “the most comprehensive assessment to date of the association between ultra-processed foods and the risk of developing cancers,” an Imperial College news report states.

The findings are of particular concern given that consumption of ultraprocessed foods has been rising rapidly in recent decades, especially in the UK and the United States, where these foodstuffs often exceed more than 50% of daily caloric intake, commented first author Kiara Chang, PhD, of the Public Health Policy Evaluation Unit at Imperial College London.

However, several experts who weighed in on the study results via the UK-based Science Media Center cautioned against drawing firm conclusions on the basis of observational data.

For example, Tom Sanders, PhD, professor emeritus of nutrition and dietetics, King’s College London, said, “The definition of ultra-processed food is so vague which makes establishing any cause-effect relationship problematic.”

Ultraprocessed foods undergo heavy processing during production. They include items such as soft drinks, breakfast cereals, and many mass-produced and ready-to-eat packaged foods. These tend to be inexpensive, easily accessible, and high in fat, sugar, salt, and artificial ingredients.

Saunders noted that smoking-related cancers were more common in those with the highest intake of these foods ― a potential confounding factor that the study authors recognize.

“The association with ultra-processed food and risk of ovarian cancer in this study is novel but given the relatively small number of cases (291) of ovarian cancer, the finding needs replication in other prospective cohorts before taking the claim that ultra-processed foods increase the risk of cancer seriously,” Sanders argued.

UPFs and Health Outcomes

Multiple studies have established links between the intake of ultraprocessed foods and obesity, type 2 diabetes, cardiovascular disease, and all-cause mortality, the investigators note.

In their study, they set out to assess the impact on cancer incidence and mortality. They identified a UK Biobank cohort of 197,426 individuals aged 40–69 years who completed multiple 24-hour dietary recalls between 2009 and 2012. Slightly more than half (54.6%) were women. Participants were followed until January 31, 2021.

Mean ultraprocessed food consumption was 22.9% of total diet, the team reports; this was based on the degree of food processing identified using the NOVA food classification system.

During the median follow-up of 9.8 years, 15,921 individuals developed cancer, and 4009 succumbed to cancer-related deaths.

The team divided consumption of ultraprocessed foods into quartiles. Among individuals with the highest consumption, in comparison with persons with the lowest, the risk of overall cancer was higher by 7%.

The incidence of lung cancer was also higher, by 25%; for brain cancer, the risk was higher by 52%; and for diffuse large B-cell lymphoma, by 63%. However, the risk of head and neck cancer was significantly lower; a stratified analysis showed lower risk patterns for head and neck cancer among never-smokers, ex-smokers, and all alcohol consumption groups, although most of these findings did not reach statistical significance.

In addition, among participants with the highest compared with the lowest consumption of ultraprocessed foods, the risk of overall cancer mortality was higher (HR, 1.17) as well as the risk for lung (HR, 1.38) and ovarian (HR, 1.91) cancer mortality.

Implications and Future Directions

The authors note, “Although causality may not be implied owing to the observational nature of the study, these findings highlight the importance of considering degrees of food processing in diets.

“In particular, the associations were found most consistent for overall cancer and ovarian cancer outcomes in women,” they write.

“These findings suggest that limiting unltra-processed food consumption may be beneficial to prevent and reduce the modifiable burdens of cancer,” they conclude.

The study was funded by Cancer Research UK and the World Cancer Research Fund. The authors and Sanders have disclosed no relevant financial relationships.

eClinicalMedicine. Published online January 31, 2022. Full text

Sharon Worcester, MA, is an award-winning medical journalist based in Birmingham, Alabama, writing for Medscape, MDedge and other affiliate sites. She currently covers oncology, but she has also written on a variety of other medical specialties and healthcare topics. She can be reached at [email protected] or on Twitter: @SW_MedReporter.

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