Caloric carcinogens: Sodas, ready meals and mass-produced bread linked to cancer, study warns

01 Feb 2023 --- The evidence against ultra-processed foods continues to mount, with Imperial College London as the latest bearer of bad news in their observational study published in eClinicalMedicine, which demonstrates that fizzy drinks, mass-produced bread, ready meals and cereals can cause cancer.

“Our findings showed that higher consumption of ultra-processed foods is linked to higher risk of developing and dying from overall cancer and ovarian cancer,” Dr. Kiara Chang, first author of the study, tells NutritionInsight.

“These suggest cutting back on ultra-processed foods as part of lifestyle interventions may have important benefits on cancer risk.”

The study found that for every 10% increase in ultra-processed food in a person’s diet, there was an increased incidence of 2% for cancer overall and a 19% increase for ovarian cancer specifically.

Each 10% increase in ultra-processed food consumption was also associated with increased mortality for cancer by 6%, alongside a 16% increase for breast cancer and a 30% increase for ovarian cancer. The link remained after adjustments were made for socio-economic, behavioral and dietary factors, such as smoking, physical activity and body mass index (BMI).

Debating dietary guidelinesUltra-processed foods have been linked once again to more than 30 forms of cancer.
The researchers note that Brazil, France and Canada are in the process of updating their national dietary guidelines with recommendations to limit such foods. Brazil has banned the marketing of ultra-processed foods in schools, for example. However, the UK does not have such measures to tackle ultra-processed foods.

“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,” says Chang. 

“Lower 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.”

Paying the highest price
Ultra-processed foods are often cheap, convenient and heavily marketed as healthy options. These foods are generally higher in salt, fat, sugar and contain artificial additives. Its link to health conditions such as obesity, Type 2 diabetes and cardiovascular disease is well-documented.

The UK Biobank records were used in a research “first” to collect information on the diets of 200 000 middle-aged adult participants. Researchers monitored participants’ health over ten years, looking at the risk of cancer overall and the specific risk of developing 34 types of cancer. They also looked at the risk of people dying from cancer.

Greater risk association
The study found that higher consumption of ultra-processed foods was associated with a greater risk of developing cancer, specifically ovarian and brain cancers. It was also associated with an increased risk of dying from cancer.

“The average person in the UK consumes more than half of their daily energy intake from ultra-processed foods,” says Chang. “This is exceptionally high and concerning as ultra-processed foods are produced with industrially derived ingredients and often use food additives to adjust color, flavor, consistency, texture, or extend shelf life.”

“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 prices and attractive packaging to promote consumption. This shows our food environment needs urgent reform to protect the population from ultra-processed foods.”

Processing the research
Previous research from the team reported the levels of consumption of ultra-processed foods in the UK, which are the highest in Europe for both adults and children. The team also found that higher consumption of ultra-processed foods was associated with a greater risk of developing obesity and Type 2 diabetes in adults and greater weight gain in children, extending from childhood to young adulthood.

The research hypothesis was “higher consumption of ultra-processed foods may be linked to adverse cancer outcomes.”

“This was an observational cohort study that followed approximately 200,000 middle-aged UK adults for ten years,” Chang outlines. 

“Statistical modeling methods were used to compare the risk of developing and dying from overall and 34 subtypes of cancer between those with higher and lower ultra-processed food consumption,” she continues.A strong link has been made to ovarian and brain cancer through consuming ultra-processed foods.

Another study linked an increased risk of obesity and obesity-related diseases in children with their mothers’ consumption of “ultra-processed” foods during pregnancy.

Observational not causal
The Cancer Research UK and World Cancer Research Fund-backed study is observational and does not show a causal link between ultra-processed foods and cancer. Further research is needed to establish a causal link.

“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 consumption levels in UK adults and children, this has important implications for future health outcomes,” says Dr. Eszter Vamos, lead author of the study.

“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.”

The research was conducted in collaboration with the International Agency for Research on Cancer, the University of São Paulo and NOVA University Lisbon.

By Inga de Jong