New Evidence That Ultra-Processed Foods May Increase Cancer Risk

A study funded by the World Cancer Research Fund and Cancer Research UK and published in eClinicalMedicine, a Lancet open access clinical journal, provides new evidence of a link between ultra-processed foods (UPFs) and an increased risk of developing cancer.

A team from Imperial College London used UK Biobank data to assess the diets of 197,426 people between the ages of 40 and 69, who completed 24-hour dietary recalls during a three-year period. Ultra Processed Food consumption was expressed as a percentage of total food intake in grams per day and was assessed against the risk of developing and/or dying from 34 different types of cancer over a period of 10-years.

After the researchers adjusted for socio-demographic factors, physical activity, smoking status, and dietary factors, it was found that a 10% increase in consumption of ultra-processed food was linked to a 2% increase in being diagnosed with any cancer and a 6% increase in dying from cancer of any kind.

The researchers also found that, with each additional 10% increase in consumption of ultra-processed food, there was a 19% increased risk for ovarian cancer and a 30% increased risk of dying from ovarian cancer. There was also a 16% increase in risk of dying from breast cancer with each 10% incremental increase in consumption of UPFs.

Further, an analysis of the top 25% tier of UPF consumption (those who consumed ultra-processed foods the most) versus the bottom 25% tier of UPF consumption (those who consumed UPFs the least) revealed a 7% higher risk of overall cancer, a 25% higher risk of developing lung cancer and a 52% higher risk of developing brain cancer in the former group as compared to the latter group.

The authors say that this study is the “most comprehensive assessment for the prospective associations between ultra-processed food consumption and risk of overall and 34 site-specific cancer incidence and associated mortality.”

Ultra-processed foods, put quite simply, are radically deviated from naturally occurring foods, and are largely devoid of whole foods— despite how they appear or the claims made on their packaging.

In addition to having undergone a significant amount of processing (which is not always a negative thing), they contain ingredients chemically formulated from food-derived substances, and not typically found in the home kitchen. Foods such as sodas, hot dogs, frozen meals, flavored yogurt, packaged snacks and fast food typically contain preservatives to extend shelf life, stabilizers to preserve structure, artificial colors to make them appear more attractive, and artificial flavors, hydrogenated oils, refined carbohydrates, excess salt, added sweeteners and fat to make them hyper-palatable.

According to Northeastern University’s Network Science Institute, 73% of the food supply in the United States is ultra-processed. Demand for these foods is driven by the fact that they are typically more affordable, heavily marketed, perceived as convenient due to long shelf life, and often contain health claims on their packaging. But the most dangerous reason for why UPFs are so heavily consumed is their hyper-palatability— they are so pleasing to the taste buds that consumers are unable to stop eating them.

Whether they are marketed as “diet” or “health” foods, UPFs are typically lower in nutritional value and contain ingredients that may be detrimental to health for a variety of reasons. Further, the additives, sweeteners and flavorings used in ultra-processed foods have proven to drive food addictions, which frequently cause over-consumption of the very foods that are marketed as “diet.”

This is not the first study to establish a correlation between ultra-processed foods and cancer. A study published in The BMJ on August 31st 2022 found a 29% higher risk for developing colorectal cancer among men who consumed high amounts of ultra-processed foods as compared to men who consumed smaller amounts of UPFs.

Other studies have established a link between ultra-processed foods and cardiovascular disease, type 2 diabetes and obesity, among other ailments.

But, given that food packaging of ultra-processed foods is not labeled as such, it is easy to buy-in to spurious health claims, over-consume, and become addicted to UPFs. In fact, January 2023 results of the University of Michigan National Poll on Healthy Aging found that 1 in 8 adults between the ages of 50 and 80 showed symptoms of addiction to highly processed foods, and recent research has shown that 1 in 5 people globally struggle with ultra-processed food addiction.

It is no wonder then that Professor Erica M. LaFata, Assistant Research Professor at the Drexel University Center for Weight, Eating, and Lifestyle Science has referred to ultra-processed food addiction as an epidemic.

But how can the average consumer differentiate between minimally processed foods and ultra-processed foods?

With the extensive selection available in most modern supermarkets, an online tool called the TrueFood dashboard takes away the mystery surrounding the degree of processing in the most common brands of food products by giving each food item a food processing score, based on the percentile of processing as compared to other items in the same category.

A more manual method of determining degree of processing in a food item is to look at the ingredients on the packaging. According to Professor Maira Bes-Rastrollo, Professor of Preventive Medicine and Public Health at the University of Navarra, a product that contains more than five ingredients is typically ultra-processed, as are foods with unrecognizable ingredients, and foods that are naturally found “fresh” but have a long shelf life. These rules also apply to foods marketed as natural, vegan, vegetarian, healthy, and low-calorie.

Research released in 2021 by the Nutritional Epidemiology Research Team lead by Benjamin Allès and Joséphine Gehring (EREN-CRESS, Inserm, INRAE, Cnam, Université Sorbonne Paris Nord) analyzed the daily food consumption of meat eaters, vegetarians, and vegans and found that veganism was correlated with increased consumption of ultra-processed foods, comprising 39.5% of the energy intake as opposed to 33% for meat-eaters.

These latest findings are not good news for many health food companies, including vegan food manufacturers that market their plant-based or low calorie ultra-processed packaged foods as “good for you.”

“The overall composition of the average U.S. diet has shifted towards a more processed diet,” says Filippa Juul, an assistant professor and postdoctoral fellow at NYU School of Public Health. “This is concerning, as eating more ultra-processed foods is associated with poor diet quality and higher risk of several chronic diseases,”

Today, close to half of all deaths are due to cancer, with incident cases projected to increase to 28.4 million by 2040, and according to the most current statistics, dietary risk factors are the leading contributors to the global burden of disease (GBD), responsible for an estimated 11 million deaths from non-communicable diseases (NCDs) or 22% of all adult deaths globally.

The World Health Organization and the Food and Agriculture Organization recommend the restriction of ultra-processed foods as part of a healthy and sustainable diet.