Researchers have produced the most comprehensive assessment to date of the association between ultra-processed foods and the risk of developing cancers.
People consume far too many ultra-processed foods and warning that a higher consumption of many of these common, everyday products could be linked to an increased risk of developing and dying from cancer.
Researchers led by Imperial College’s School of Public Health found breakfast cereals, mass-produced bread, ready meals, ice cream, ham and crisps are among the foodstuffs the study, funded by Cancer Research UK and the World Cancer Research Fund, suggests might be linked to various cancers.
The researchers also called for called for front-of-pack warning labels, saying British people eat far too many ultra-processed foods – often called UPFs.
Ultra-processed foods have been heavily processed during their production, for instance fizzy drinks, mass-produced packaged breads, many ready meals and most breakfast cereals. They usually contain ingredients that people would not add when they are cooking homemade food, such as chemicals, colourings, sweeteners and preservatives and artificial additives, and usually relatively cheap, convenient, and heavily marketed, often as healthy options.
But they are also often higher in salt, fat, sugar. It is now well documented that they are linked with a range of poor health outcomes, including obesity, type 2 diabetes and cardiovascular disease.
Dr Kiara Chang, who worked on the research, said the average person in the UK relies on UPFs for more than half of their daily energy intake, with poorer people more vulnerable to taking the cheap and unhealthy option.
She said: “Ultra-processed foods are everywhere and highly marketed with cheap price and attractive packaging to promote consumption. This shows our food environment needs urgent reform to protect the population from ultra-processed foods.”
Not all processed food is bad. For example, reports The Independent, the NHS says some foods need processing to make them safe, like milk, which needs to be pasteurised to remove bacteria.
A number of previous studies have suggested a link between UPFs and heart disease, dementia, obesity and type 2 diabetes.
In the study, published in eClinicalMedicine, the team used UK Biobank data to examine the diets of 197 426 people aged 40 to 69. Their health was tracked over a decade and their risk of developing cancer or dying from it was also analysed.
The study found that higher consumption of ultra-processed foods was associated with a greater risk of developing cancer overall, and specifically ovarian and brain cancers. It was also linked to an increased risk of dying from cancer.
The researchers found that for every 10% increase in ultra-processed food in a person’s diet, there was a 2% increased risk of cancer overall, and a 19% increased risk for ovarian cancer specifically.
These links held true even after adjusting for factors that may alter the results, such as exercise, BMI and deprivation.
The Imperial team carried out the studyin collaboration with researchers from the International Agency for Research on Cancer (IARC), University of São Paulo, and NOVA University Lisbon.
Study details
Ultra-processed food consumption, cancer risk and cancer mortality: a large-scale prospective analysis within the UK Biobank
Kiara Chang, Marc J. Gunter, Fernanda Rauber, Renata Levy, Inge Huybrechts, Nathalie Kliemann.
Published in The Lancet eClinical Medicine on 31 January 2023
Summary
Background
Global dietary patterns are increasingly dominated by relatively cheap, highly palatable, and ready-to-eat ultra-processed foods (UPFs). However, prospective evidence is limited on cancer development and mortality in relation to UPF consumption. This study examines associations between UPF consumption and risk of cancer and associated mortality for 34 site-specific cancers in a large cohort of British adults.
Methods
This study included a prospective cohort of UK Biobank participants (aged 40–69 years) who completed 24-h dietary recalls between 2009 and 2012 (N = 197426, 54.6% women) and were followed up until Jan 31, 2021. Food items consumed were categorised according to their degree of food processing using the NOVA food classification system. Individuals’ UPF consumption was expressed as a percentage of total food intake (g/day). Prospective associations were assessed using multivariable Cox proportional hazards models adjusted for baseline socio-demographic characteristics, smoking status, physical activity, body mass index, alcohol and total energy intake.
Findings
The mean UPF consumption was 22.9% (SD 13.3%) in the total diet. During a median follow-up time of 9.8 years, 15,921 individuals developed cancer and 4009 cancer-related deaths occurred. Every 10 percentage points increment in UPF consumption was associated with an increased incidence of overall (hazard ratio, 1.02; 95% CI, 1.01–1.04) and specifically ovarian (1.19; 1.08–1.30) cancer. Furthermore, every 10 percentage points increment in UPF consumption was associated with an increased risk of overall (1.06; 1.03–1.09), ovarian (1.30; 1.13–1.50), and breast (1.16; 1.02–1.32) cancer-related mortality.
Interpretation
Our UK-based cohort study suggests that higher UPF consumption may be linked to an increased burden and mortality for overall and certain site-specific cancers especially ovarian cancer in women.
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