Researchers from the Imperial School of Public Health have conducted the most comprehensive assessment to date of the relationship between highly processed foods and the risk of developing cancer. Ultra-processed foods are foodstuffs that are heavily processed during their production, such as sodas, mass-produced packaged breads, many convenience meals, and most breakfast cereals.
Ultra-processed foods are generally relatively inexpensive, convenient and heavily marketed, and are often viewed as healthy options. But these foods are also often higher in salt, fat, sugar, and contain artificial additives. They are now well documented to be linked to a number of poor health outcomes, including obesity, type 2 diabetes, and cardiovascular disease.
The first study of its kind in the UK used UK Biobank records to gather information on the diets of 200,000 middle-aged adult participants. The researchers monitored the participants’ health over a 10-year period and looked at the overall risk of developing any cancer, as well as the risk of developing 34 types of cancer. They also looked at people’s risk of dying from cancer.
The study found that higher consumption of ultra-processed foods was associated with a higher risk of developing cancer in general and with ovarian and brain cancers in particular. It has also been associated with an increased risk of dying from cancer, particularly ovarian and breast cancers.
For every 10 percent increase in ultra-processed food in a person’s diet, there was a 2 percent increase in the incidence of cancer overall and a 19 percent increase in ovarian cancer in particular.
Every 10 percent increase in ultra-processed food consumption was associated with a 16 percent increase in breast cancer and a 30 percent increase in ovarian cancer, as well as a 6 percent increase in cancer deaths overall.
These links remained after adjusting for a range of socio-economic, behavioral, and nutritional factors, such as smoking status, physical activity, and body mass index (BMI).
The Imperial team conducted the study, published in eClinicalMedicine, in collaboration with researchers from the International Agency for Research on Cancer (IARC), the University of São Paulo, and the NOVA University of Lisbon.
Previous research by the team reported consumption levels of ultra-processed foods for both adults and children in the UK, with the highest in Europe. The team also found that higher consumption of ultra-processed foods was associated with greater risk of developing type 2 diabetes in UK adults and greater weight gain in UK children spanning from childhood to young adulthood.
Dr Eszter Vamos, lead author of the study, from Imperial College London’s School of Public Health, said: “This study adds to the growing evidence that highly processed foods can adversely affect our health, including our risk. Given the high consumption levels in adults and children in the UK, this has important implications for future health outcomes.
“While our study cannot prove a causal relationship, other available evidence suggests that reducing hyperprocessed foods in our diet can provide significant health benefits. More research is needed to confirm these findings and understand the best public health strategies to reduce the prevalence and harm of highly processed foods in our diet. ”
Dr Kiara Chang, first author of the study, from Imperial College London’s School of Public Health, said: “The average person in the UK consumes more than half of their daily energy intake from ultra-processed foods. This is extremely high and of concern, as ultra-processed foods are produced with industrially derived ingredients and often use food additives to adjust color, taste, consistency, texture or extend shelf life.
“Our bodies may not respond to these ultra-processed ingredients and additives as they do to minimally processed fresh and nutritious foods. However, highly processed foods are ubiquitous and highly marketed with cheap price and attractive packaging to encourage consumption. This shows that our food environment needs urgent reform to protect the population from ultra-processed foods.”
The World Health Organization and the United Nations Food and Agriculture Organization have previously recommended limiting highly processed foods as part of a healthy and sustainable diet.
There are ongoing efforts to reduce ultra-processed food consumption worldwide, 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 over-processed foods in schools. There is currently no similar measure in the UK to combat excessively processed foods.
“Low-income households are particularly vulnerable to these cheap and unhealthy ultra-processed foods. Minimally processed and freshly prepared meals should be subsidized to ensure everyone has access to healthy, nutritious and affordable options.”
The researchers note that their study was observational, so due to the observational nature of the research, it did not show a causal link between highly processed foods and cancer. More work in this area is needed to establish a causal link.
This work was funded by Cancer Research UK and the World Cancer Research Fund.