Ultra-Processed Foods and Increased Cancer Risk

A new European study published in The BMJ shows a potential link between the consumption of “ultra-processed” foods and illness — specifically, a 10% increase in the proportion of these foods in a person’s diet was associated with a more than 10% increase in the risk of cancer.

Ultra-processed foods are characterized by lower nutritional quality and the presence of additives such as flavoring agents, color, emulsifiers, and non-sugar sweeteners. Examples are mass produced packaged breads and buns, sweet or savory packaged snacks, industrialized candy and desserts, sodas and sweetened drinks, and chicken or fish nuggets, and processed meats — basically, any food that contains chemical ingredients or ingredients you don’t recognize as “food” are considered to be ultra-processed.

Previous studies have shown these ultra-processed foods to be associated with higher risks of overweight, obesity, and hypertension.

“During the last decades in many countries in Europe, and also in the U.S. and other countries, diets have really shifted toward a dramatic increase in ultra-processed food consumption,” says Mathilde Touvier, a senior researcher in nutritional epidemiology and a contributor to the report. “There are several studies suggesting they now represent between 25 and 50% of total daily energy intake.”

The study shows a correlation between the consumption of ultra-processed foods and cancer, but it is not confirmation of causation. There could be other contributing factors that are unaccounted for by the study’s available data set; that would be the responsible, scientifically conservative approach to interpreting the study’s results.

For most of us, however, we already have our suspicions about these foods and this is just more hydrogenated icing on the cake.

If these foods really are contributing to cancer, the next questions we need to ask are why? What about them is driving the increased risk? The following hypotheses have been proposed:

  • These foods are supplanting more nutritionally dense foods we would have been eating otherwise — things like fruits and vegetables that might have cancer-fighting properties.
  • Ultra-processed foods tend to be higher in total fat, saturated fat, salt, and added sugar, and are lower in fiber than other foods.
  • The additives used in ultra-processing, such as for added flavoring and color, are directly responsible.
  • Chemicals used in product packaging may have carcinogenic properties that come into contact with the food.
  • There may be carcinogenic “neoformed contaminants,” which are not part of the initial ingredient list but become present during the production process.

Again, we can’t yet say for sure based on this study that ultra-processed foods increase cancer risk — just that they’re associated with increased risk. But if they do … well, don’t be surprised if the cause turns out to be more than a few of those bulleted possibilities.

In the meantime, it can’t hurt to shift our diets away from ultra-processed foods and back toward other options.

The study used the NOVA classification to define what an ultra-processed food is. NOVA puts food into four groups: unprocessed or minimally processed foods; processed culinary ingredients; processed foods; and ultra-processed foods. Cutting back on group 4 in favor of items from groups 1, 2, and 3 would be enough to reduce your cancer risk, at least according to the correlations of the study.

Group 1. Unprocessed or minimally processed foods.

Unprocessed foods are edible parts of plants or of animals (including eggs and milk), and also fungi, algae and water, after separation from nature.

Minimally processed foods are natural foods altered by processes such as removal of inedible or unwanted parts, drying, crushing, grinding, fractioning, filtering, roasting, boiling, pasteurisation, refrigeration, freezing, placing in containers, vacuum packaging, or non- alcoholic fermentation. None of these processes adds substances such as salt, sugar, oils or fats to the original food.

Group 2. Processed culinary ingredients.

These are substances obtained directly from group 1 foods or from nature by processes such as pressing, refining, grinding, milling, and spray drying.

The purpose of processing here is to make products used in home and restaurant kitchens to prepare, season and cook group 1 foods and to make with them varied and enjoyable hand-made dishes, soups and broths, breads, preserves, salads, drinks, desserts and other culinary preparations.

Group 3. Processed foods.

These are relatively simple products made by adding sugar, oil, salt or other group 2 substances to group 1 foods. Most processed foods have two or three ingredients. Processes include various preservation or cooking methods, and, in the case of breads and cheese, non-alcoholic fermentation.

The main purpose of the manufacture of processed foods is to increase the durability of group 1 foods, or to modify or enhance their sensory qualities.

Typical examples of processed foods are canned or bottled vegetables, fruits and legumes; salted or sugared nuts and seeds; salted, cured, or smoked meats; canned fish; fruits in

syrup; cheeses and unpackaged freshly made breads

Processed foods may contain additives used to preserve their original properties or to resist microbial contamination. Examples are fruits in syrup with added anti-oxidants, and dried salted meats with added preservatives.

Group 4. Ultra-processed foods.

These are industrial formulations typically with five or more and usually many ingredients. Such ingredients often include those also used in processed foods, such as sugar, oils, fats, salt, anti-oxidants, stabilizers, and preservatives. Ingredients only found in ultra-processed products include substances not commonly used in culinary preparations, and additives whose purpose is to imitate sensory qualities of group 1 foods or of culinary preparations of these foods, or to disguise undesirable sensory qualities of the final product. Group 1 foods are a small proportion of or are even absent from ultra-processed products.

Substances only found in ultra-processed products include some directly extracted from foods, such as casein, lactose, whey, and gluten, and some derived from further processing

of food constituents, such as hydrogenated or interesterified oils, hydrolysed proteins, soy protein isolate, maltodextrin, invert sugar and high fructose corn syrup. Classes of additive only found in ultra-processed products include dyes and other colours, colour stabilisers, flavours, flavour enhancers, non-sugar sweeteners, and processing aids such as carbonating, firming, bulking and anti-bulking, de-foaming, anti-caking and glazing agents, emulsifiers, sequestrants and humectants.

Several industrial processes with no domestic equivalents are used in the manufacture of ultra-processed products, such as extrusion and moulding, and pre-processing for frying.

The main purpose of industrial ultra-processing is to create products that are ready to eat, to drink or to heat, liable to replace both unprocessed or minimally processed foods that are naturally ready to consume, such as fruits and nuts, milk and water, and freshly prepared drinks, dishes, desserts and meals. Common attributes of ultra-processed products are hyper-palatability, sophisticated and attractive packaging, multi-media and other aggressive marketing to children and adolescents, health claims, high profitability, and branding and ownership by transnational corporations.