The Untold Cancer Risk of Ultra-Processed Food
By UNIVERSITY OF BRISTOL
Eating more ultra-processed foods (UPFs) may be associated with a higher risk of developing cancers of upper aerodigestive tract (including the mouth, throat, and esophagus), according to a new study led by researchers from the University of Bristol and the International Agency for Research on Cancer (IARC).
The authors of this international study, which analyzed diet and lifestyle data on 450,111 adults who were followed for approximately 14 years, say obesity associated with the consumption of UPFs may not be the only factor to blame. The study was published recently in the European Journal of Nutrition.
Previous Studies and New Insights
Several studies have identified an association between
UPF consumption and cancer, including a recent study that
looked at the association between UPFs and 34 different cancers in the largest
cohort study in Europe, the European Prospective
Investigation into Cancer and Nutrition (EPIC) cohort.
As more evidence emerges about the associations between eating UPFs and adverse health outcomes, researchers from the Bristol Medical School and IARC wanted to explore this further.
Since many UPFs have an
unhealthy nutritional profile, the team sought to establish whether the
association between UPF consumption and head and neck cancer and oesophageal
adenocarcinoma (a cancer of the esophagus) in EPIC could be explained by an
increase in body fat.
Results from the team’s analyses showed that eating 10% more UPFs is associated with a 23% higher risk of head and neck cancer and a 24% higher risk of oesophageal adenocarcinoma in EPIC.
Increased body fat only
explained a small proportion of the statistical association between UPF
consumption and the risk of these upper-aerodigestive tract cancers.
Understanding the Risks and Implications
Fernanda Morales-Berstein, a Wellcome Trust PhD student at the University of Bristol and the study’s lead author, explained: “UPFs have been associated with excess weight and increased body fat in several observational studies.
This makes sense, as they are generally tasty,
convenient, and cheap, favoring the consumption of large portions and an
excessive number of calories. However, it was interesting that in our study the
link between eating UPFs and upper-aerodigestive tract cancer didn’t seem to be
greatly explained by body mass index and waist-to-hip ratio.”
The authors suggest that other mechanisms could explain
the association. For example, additives including emulsifiers and artificial
sweeteners which have been previously associated with disease risk, and
contaminants from food packaging and the manufacturing process, may partly
explain the link between UPF consumption and upper-aerodigestive tract cancer
in this study.
However, Fernanda Morales-Berstein and colleagues did add caution regarding their findings and suggest that the associations between UPF consumption and upper-aerodigestive tract cancers found in the study could be affected by certain types of bias.
This would explain why they found evidence
of an association between higher UPF consumption and increased risk of
accidental deaths, which is highly unlikely to be causal.
George Davey Smith, Professor of Clinical Epidemiology
and Director of the MRC Integrative Epidemiology Unit at the University of
Bristol, and co-author on the paper, said: “UPFs are clearly associated with
many adverse health outcomes, yet whether they actually cause these, or whether
underlying factors such as general health-related behaviors and socioeconomic
position are responsible for the link, is still unclear, as the association
with accidental deaths draws attention to.”
Need for Further Research
Inge Huybrechts, Team head of the Lifestyle exposures and
interventions team at IARC, added: “Cohorts with long-term dietary follow-up
intake assessments, considering also contemporary consumption habits, are
needed to replicate these study’s findings, as the EPIC dietary data were
collected in the 1990s, when the consumption of UPFs was still relatively low.
As such associations may potentially be stronger in cohorts including recent
dietary follow-up assessments.”
Further research is needed to identify other mechanisms,
such as food additives and contaminants, which may explain the links observed.
However, based on the finding that body fat did not greatly explain the link
between UPF consumption and upper-aerodigestive tract cancer risk in this
study, Fernanda Morales-Berstein, suggested: “Focusing solely on weight loss
treatment, such as Semaglutide, is unlikely to greatly contribute to the
prevention of upper-aerodigestive tract cancers related to eating UPFs.”
Dr. Helen Croker, Assistant Director of Research and
Policy at World Cancer Research Fund, added: “This study adds to a growing pool
of evidence suggesting a link between UPFs and cancer risk. The association
between a higher consumption of UPFs and an increased risk of developing
upper-aerodigestive tract cancer supports our Cancer Prevention Recommendations
to eat a healthy diet, rich in wholegrains, vegetables, fruit, and beans.”
Reference: “Ultra-processed foods, adiposity and risk of
head and neck cancer and oesophageal adenocarcinoma in the European Prospective
Investigation into Cancer and Nutrition study: a mediation analysis” by
Fernanda Morales-Berstein, Carine Biessy, Vivian Viallon, Ana Goncalves-Soares,
Corinne Casagrande, Bertrand Hémon, Nathalie Kliemann, Manon Cairat, Jessica
Blanco Lopez, Aline Al Nahas, Kiara Chang, Eszter Vamos, Fernanda Rauber,
Renata Bertazzi Levy, Diana Barbosa Cunha, Paula Jakszyn, Pietro Ferrari, Paolo
Vineis, Giovanna Masala, Alberto Catalano, Emily Sonestedt, Yan Borné, Verena
Katzke, Rashmita Bajracharya, Claudia Agnoli, Marcela Guevara, Alicia Heath,
Loredana Radoï, Francesca Mancini, Elisabete Weiderpass, José María Huerta,
María-José Sánchez, Anne Tjønneland, Cecilie Kyrø, Matthias B. Schulze, Guri
Skeie, Marko Lukic, Tonje Braaten, Marc Gunter, Christopher Millett, Antonio
Agudo, Paul Brennan, M. Carolina Borges, Rebecca C. Richmond, Tom G.
Richardson, George Davey Smith, Caroline L. Relton, Inge Huybrechts and on
behalf of the EPIC Network, 22 November 2023, European Journal of Nutrition.
DOI:
10.1007/s00394-023-03270-1
The study was funded by the Wellcome Trust; Cancer
Research UK; World Cancer Research Fund International; Institut National du
Cancer; Horizon 2020 ‘Dynamic longitudinal exposome trajectories in
cardiovascular and metabolic non-communicable diseases’ study; University of
Bristol Vice Chancellor’s Fellowship; British Heart Foundation and the Medical
Research Council.