The observational study, described as the ‘most comprehensive assessment to date’ of the association between ultra-processed food and cancer risk, was conducted by researchers from Imperial’s School of Public Health. It defined ultra-processed foods as products that have been ‘heavily processed during their production’ such as fizzy drinks, mass-produced packaged breads, ready meals and ‘most’ breakfast cereals.
The researchers used UK Biobank records to collect information on the diets of 200,000 middle-aged adults. They monitored participants health over a ten year period, looking at the risk of developing any cancer overall as well as more specific risk of developing 34 different types of cancer. The also looked at whether there was any correlation between diet and cancer treatment outcomes to determine whether people who eat more ultra-processed foods are at greater risk of cancer mortality.
The results found that a higher consumption of ultra-processed foods is indeed associated with a greater risk of developing cancer. Specifically, risk is heightened ovarian and brain cancers. For every 10% increase in ultra-processed food intake, there was an increased incidence of 2% for cancer overall, and a 19% increase for ovarian cancer specifically.
Higher ultra-processed food consumption was also linked to greater risk of dying from cancer. For every 10% more processed food in a person’s diet, there was a 6% increase in cancer mortality overall, with a 16% increase in mortality rate for breast cancer and a 30% rise for ovarian cancer.
These links remained after adjusting for a range of socio-economic, behavioural and dietary factors, such as smoking status, physical activity and body mass index (BMI).
“This study adds to the growing evidence that ultra-processed foods are likely to negatively impact our health including our risk for cancer. Given the high levels of consumption in UK adults and children, this has important implications for future health outcomes,” Dr Eszter Vamos, lead senior author for the study, from Imperial College London’s School of Public Health, said.
The researchers note that their study is observational, so does not show a causal link between ultra-processed foods and cancer due to the observational nature of the research. More work is needed in this area to establish a causal link. “Although our study cannot prove causation, other available evidence shows that reducing ultra-processed foods in our diet could provide important health benefits. Further research is needed to confirm these findings and understand the best public health strategies to reduce the widespread presence and harms of ultra-processed foods in our diet.”
Labelling and taxation needed to cut consumption of ultra-processed foods
According to the researchers: “Ultra-processed foods are often relatively cheap, convenient, and heavily marketed, often as healthy options. But these foods are also generally higher in salt, fat, sugar, and contain artificial additives.” They claim it is now ‘well documented’ that they are linked with a range of poor health outcomes including obesity, type 2 diabetes and cardiovascular disease.
Previous research from the Imperial team has suggested the amount of ultra-processed food consumed by adults and children in the UK are the highest in Europe.
“The average person in the UK consumes more than half of their daily energy intake from ultra-processed foods. This is exceptionally high and concerning as ultra-processed foods are produced with industrially derived ingredients and often use food additives to adjust colour, flavour, consistency, texture, or extend shelf life,” stressed Dr Kiara Chang, first author for the study.
Dr Chang believes that the negative health associations of ultra-processed foods should be addressed by policy targeting the food environment to which consumers are exposed. “Our bodies may not react the same way to these ultra-processed ingredients and additives as they do to fresh and nutritious minimally processed foods. However, 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,” she argued.
The World Health Organisation and the United Nations’ Food and Agriculture Organisation has previously recommended restricting ultra-processed foods as part of a healthy sustainable diet. The researches noted there are ongoing efforts to reduce ultra-processed food consumption around the world, with countries such as Brazil, France and Canada updating their national dietary guidelines with recommendations to limit such foods. Brazil has also banned the marketing of ultra-processed foods in schools. There are currently no similar measures to tackle ultra-processed foods in the UK.
“We need clear front of pack warning labels for ultra-processed foods to aid consumer choices, and our sugar tax should be extended to cover ultra-processed fizzy drinks, fruit-based and milk-based drinks, as well as other ultra-processed products,” Dr Chang urged.
The health policy expert also stressed that there is a socio-economic dimension to the burden that ultra-processed food consumption places on the UK population. “Lower income households are particularly vulnerable to these cheap and unhealthy ultra-processed foods. Minimally processed and freshly prepared meals should be subsidised to ensure everyone has access to healthy, nutritious and affordable options.”
The Imperial team carried out the study, which is published in eClinicalMedicine, in collaboration with researchers from the International Agency for Research on Cancer (IARC), University of São Paulo, and NOVA University Lisbon. It was funded by Cancer Research UK and the World Cancer Research Fund.
‘Ultra-processed food consumption, cancer risk and cancer mortality: a large-scale prospective analysis within the UK Biobank’