A major 2018 prospective study 1 , involving 104,980 French participants, shows a shocking link between ultra-processed foods and cancer. And don’t think that this term ‘ultra-processed’ refers to foods that most of us are unlikely to eat – unless you eat an exclusively non-SOS WFPB diet, most people in our societies are most likely to be eating these foods on a regular basis.
At the risk of repeating myself…
Whilst the press is treating this research as having just been released2 , a previous blog3 looked at this research when it was first published in February 2018 (maybe it takes this length of time for the mainstream media to catch up with such research findings). In any case, because the information is so important, it seems worthwhile reiterating some points, as well as processing some food definitions .
The BMJ study, entitled “Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort study“, looked for associations between ultra-processed food intake and risk of overall, breast, prostate, and colorectal cancer. To do this, they followed a large number of individuals for over 8 years, getting a wide range of data from them and analysing the results to see if there was a convincing link between consumption of so-called ‘ultra-processed foods’ and various forms of cancer.
And, yes, they did. They concluded:
“In this large prospective study, a 10% increase in the proportion of ultra-processed foods in the diet was associated with a significant increase of greater than 10% in risks of overall and breast cancer.”
Pretty clear confirmation of a relationship although, of course, in any observational study, no matter how long and far-reaching, there’s always a question of whether a causal relationship exists between the two variables.
Irrespective of Dietary Habits
The relationship between 10% increase in ultra-processed food consumption and over 10% increased risk of developing various forms of cancer did not vary with diet. This means that, regardless of whether you’re a vegan, vegetarian, omnivore, or have a higher or lower ratio of particular macronutrients (carbs, fat or protein) in your diet, the risk remained statistically the same: anyone, no matter how healthy your diet, eating these ultra-processed foods appears to have their risk of cancer increased by the same percentage.
The 4 Definitions of Processed
In the study, they define 4 groups of foods, as outlined by the NOVA Group 4 .
- a. Unprocessed or b. minimally-processed foods
- Processed culinary ingredients
- Processed foods
- Ultra-processed food and drink products
I’m going to explain the above 4 classifications in a fair bit of detail. I think this important since most of us are going to get confused by what differences exist between these groups. Indeed, most of only use two terms, “unprocessed” and “processed”, and even this is mostly done without being absolutely certain what we’re really talking about.
Group 1. Unprocessed or minimally processed foods
a. Unprocessed (or natural) foods are edible parts of plants (seeds, fruits, leaves, stems, roots) or of animals (muscle, offal, eggs, milk), and also fungi, algae and water, after separation from nature.
b. Minimally processed foods are natural foods altered by processes such as:
- removal of inedible or unwanted parts
- fractioning 5
- placing in containers
- nonalcoholic fermentation
None of these processes adds substances such as salt, sugar, oils or fats to the original food.
The main purpose of the processes used in the production of group 1a. foods is to extend the life of unprocessed foods, allowing their storage for longer use, such as chilling, freezing, drying, and pasteurising.
Other purposes include facilitating or diversifying food preparation, such as:
- removal of inedible parts
- fractioning vegetables
- crushing or grinding seeds
- roasting coffee beans or tea leaves
- fermentation of milk to make yoghurt
Foods included in Group 1:
- fresh, squeezed, chilled, frozen, or dried fruits and leafy and root vegetables
- grains such as brown, parboiled or white rice, corn cob or kernel, wheat berry or grain
- legumes such as beans of all types, lentils, chickpeas
- starchy roots and tubers such as potatoes and cassava, in bulk or packaged
- fungi such as fresh or dried mushrooms
- meat, poultry, fish and seafood, whole or in the form of steaks, fillets and other cuts, or chilled or frozen
- milk, pasteurised or powdered
- fresh or pasteurised fruit or vegetable juices without added sugar, sweeteners or flavours
- grits, flakes or flour made from corn, wheat, oats, or cassava
- pasta, couscous and polenta made with flours, flakes or grits and water
- tree and ground nuts and other oil seeds without added salt or sugar
- spices such as pepper, cloves and cinnamon
- herbs such as thyme and mint, fresh or dried
- plain yoghurt with no added sugar or artificial sweeteners added
- tea, coffee, drinking water
Group 1 also includes foods made up from two or more items in this group:
- dried mixed fruits
- granola made from cereals, nuts and dried fruits with no added sugar, honey or oil
- foods with vitamins and minerals added generally to replace nutrients lost during processing, such as wheat or corn flour fortified with iron or folic acid
Group 1 items may infrequently contain additives used to preserve the properties of the original food:
- vacuum-packed vegetables with added anti-oxidants
- ultra-pasteurised milk with added stabilisers.
Group 2 – Processed culinary ingredients
These are substances obtained directly from group 1 foods or from nature by processes such as:
- spray drying
Purpose of processing – to produce products that can be used in both 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 2 items are rarely consumed in the absence of group 1 foods, for instance:
- salt mined or from seawater
- sugar and molasses obtained from cane or beet
- honey extracted from combs
- syrup from maple trees
- vegetable oils crushed from olives or seeds
- butter and lard obtained from milk and pork
- starches extracted from corn and other plants
Products consisting of two group 2 items remain in this group, such as:
- salted butter
- group 2 items with added vitamins or minerals (e.g. iodised salt)
- vinegar made by acetic fermentation of wine
- some alcoholic drinks (see group 4)
Group 2 items may contain additives used to preserve the product’s original properties, such as:
- vegetable oils with added anti-oxidants
- cooking salt with added anti-humectants 6
- vinegar with added preservatives that prevent microorganism proliferation
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.
Main purpose of processed food manufacture is to increase durability of group 1 foods, or to modify or enhance their sensory qualities.
Typical examples of group 3 processed foods include:
- canned or bottled vegetables
- canned or bottled fruits and legumes
- salted or sugared nuts and seeds
- salted, cured, or smoked meats [including fish]
- canned fish
- fruits in syrup
- unpackaged freshly-made breads
Processed foods may contain additives used to preserve their original properties or to resist microbial contamination. For instance:
- fruits in syrup with added anti-oxidants
- dried salted meats with added preservatives
- alcoholic drinks produced by fermentation of group 1 foods (such as beer, cider and wine)
Group 4. – Ultra-processed food and drink products
These are industrial formulations typically with five or more and usually many ingredients, including those also used in group 3 processed foods, such as:
Ingredients only found in group 4 ultra-processed products include:
- substances not commonly used in culinary preparations
- additives whose purpose is to imitate sensory qualities of group 1 foods
- additives whose purpose is to imitate culinary preparations of group 1 foods
- additives used to disguise undesirable sensory qualities of the final product
Group 1 foods are a small proportion of or are even absent from group 4 ultra-processed products.
Substances only found in ultra-processed products include:
- some directly extracted from foods, for instance:
- some derived from further processing of food constituents, for instance:
Classes of additive only found in ultra-processed products include:
- dyes and other colours
- colour stabilisers
- flavour enhancers
- non-sugar sweeteners
- processing aids, such as:
Several industrial processes with no domestic equivalents are used in the manufacture of group 4 ultra-processed products, such as extrusion 15 , 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. Unfortunately, these will probably replace both unprocessed or minimally processed foods in the diet – the latter being naturally ready to consume, such as fruits and nuts, milk and water, and freshly prepared drinks, dishes, desserts and meals.
Common attributes of group 4 ultra-processed products are:
- sophisticated and attractive packaging
- multi-media and other aggressive marketing to children and adolescents
- health claims
- high profitability
- branding/ownership by transnational corporations
Examples of typical group 4 ultra-processed products include:
- carbonated drinks
- sweet or savoury packaged snacks [including crisps – potato chips in the US]
- candies (confectionery)
- mass-produced packaged breads and buns
- margarines and spreads
- cookies (biscuits)
- cakes and cake mixes
- breakfast ‘cereals’
- ‘cereal’ and ‘energy’ bars
- ‘energy’ drinks
- milk drinks
- ‘fruit’ yogurts
- ‘fruit’ drinks
- cocoa drinks
- meat and chicken extracts
- ‘instant’ sauces
- infant formulas
- follow-on milks
- other baby products
- ‘health’ and ‘slimming’ products, such as:
- powdered meal substitutes
- ‘fortified’ meal substitutes
- many ready to heat products, including:
- pre-prepared pies
- pasta dishes
- pizza dishes
- poultry ‘nuggets’
- fish ‘nuggets’ or ‘sticks’
- hot dogs
- other reconstituted meat products
- powdered and packaged ‘instant’ soups
- ‘instant’ noodles
- powdered and ‘instant’ desserts
Group 4 foods also include any products made solely of group 1 or group 3 foods which also contain cosmetic or sensory intensifying additives, such as:
- plain yoghurt with added artificial sweeteners
- breads with added emulsifiers
Group 4 also includes any alcoholic drinks which are identified as foods which are produced by fermentation of group 1 foods followed by distillation of the resulting alcohol, such as:
Everything but group 4’s okay, then?
Short answer? No.
Adding single additives like salt 16 , sugar 17 , and oils 18 have detrimental effects on health. All animal foods are associated with serious health issues 19 , compared with plant foods 20 . Cured/smoked fish, in particular, though it’s in group 3, has been shown to be carcinogenic 21 .
It’s also worth noting that this is a survey from the country historically known to be the centre of culinary excellence – noted for its supposedly health Mediterranean diet 18 . It would be no surprise, then, that populations in other Western countries – particularly the UK and USA 22 – have considerably more consumption of ultra-processed foods.
All clear now?
If you’ve got all the food types, food combinations and preparation methods nice and sorted in your head, then you’re cleverer than most of us. Whilst some elements have been made clear by this research, there remains some lack of clarity about which items out of groups 1 to 3 might still cause adverse effects.
Perhaps, the only sure way to know that the foods you are eating offer optimal protection against developing cancer is to eat a non-SOS WFPB diet. Foods on the plate that look remarkably similar to how they looked when they were first harvested.
Podcast by the authors
You may be interested in listing to a short podcast 23 , where two of the authors of the above study are interviewed by a representative from the BMJ (British Medical Journal):
It would surprise me greatly if many people reading this could say with hand on heart that they never eat any of the above group 4 foods. They have become such a mainstay of our modern Western diets that they go largely unnoticed and accepted without question.
Are the scientists helping?
Have you ever heard anyone talking about ‘ultra-processed’ foods before? Of course not – we conventionally refer to group 4 foods as simply ‘processed foods’.
Whether the likes of McDonald’s Egg McMuffin or Walker’s Prawn-Flavoured Crisps will ever be referred to as ‘ultra-processed’ foods by the general population is, I think, unlikely. So, once again, there’ll be an unfortunate disconnect between the technical terms used in scientific reports and the terminology used ‘on the street’.
However, the study makes one thing certain: If you want to maintain optimal health and longevity, you’re not going to get it by eating the processed foods that most people eat, most days.
With a greater than 10% increase of an early (probably painful and humiliating) death from every 10% increase in the percentage of processed (group 4) foods we can’t resist stuffing into our mouths – what’s the difference between eating this junk or smoking a few cigarettes a day?
Finally, you may like to have a go at the quiz below.
- BMJ. 2018 Feb 14;360:k322. doi: 10.1136/bmj.k322. Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort. Fiolet T, Srour B, Sellem L, Kesse-Guyot E, Allès B, Méjean C, Deschasaux M, Fassier P, Latino-Martel P, Beslay M, Hercberg S, Lavalette C, Monteiro CA, Julia C, Touvier M.
- Daily Telegraph 13th February 2019: How to identify ‘ultra-processed’ foods – the grub that’s linked to death
- Ultra-Processed Food & Cancer
- NOVA Group: Food classification. Public health
NOVA. The star shines bright.
- “Fractioning” foods or, simply, “fractionation” is a separation process in which a certain quantity of a mixture (gas, solid, liquid, enzymes, suspension, or isotope) is divided during a phase transition, into a number of smaller quantities in which the composition varies according to a gradient.
- An anti-humectant (or anti-humidity) product is a moisture blocker which aims to resist potential moisture intrusion.
- Hydrogenated oils are oils treated with hydrogen. It is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic compounds.
- interesterified oils ((Interesterified oils or fat is a type of oil where the fatty acids have been moved from one triglyceride molecule to another. This is generally done to modify the melting point, slow rancidification and create an oil more suitable for deep frying or making margarine with good taste and low saturated fat content.
- Hydrolysed protein is a protein that has been at least partially hydrolysed or broken down into its component amino acids. While many means of achieving this exist, two of the most common methods are prolonged boiling in a strong acid or strong base (alkaline), or using an enzyme such as pancreatic protease to simulate the naturally occurring hydrolytic process, where hydrogen and oxygen molecules in water are separated using electricity.
- Soy protein isolate is produced through a process called hexane extraction. The fats are separated from the soybean in a hexane bath. Hexane is a gasoline byproduct and the USDA classifies it as a neurotoxin which they do not allow to be used in food defined as organic. Once the fats are removed from the soybean, it’s then soaked in an ethanol or an acidic bath to remove carbohydrates and any lingering flavour.
- Maltodextrin is a polysaccharide that is used as a food additive. It is produced from starch by partial hydrolysis and is usually found as a white hygroscopic spray-dried powder. Maltodextrin is easily digestible, being absorbed as rapidly as glucose and might be either moderately sweet or almost flavourless.
- Inverted sugar (also called inverted sugar syrup) is a mixture of two simple sugars – glucose and fructose. It’s made by heating sucrose with water. Sweeter than table sugar, the foods containing it can retain moisture and, thus, crystallise less easily. Bakers, who call it ‘invert syrup’, may use it more than other sweeteners.
- Dangerous stuff: BMC Nephrol. 2018 Nov 8;19(1):315. doi: 10.1186/s12882-018-1105-0. Fructose increases risk for kidney stones: potential role in metabolic syndrome and heat stress. Johnson RJ, Perez-Pozo SE, Lillo JL, Grases F, Schold JD, Kuwabara M, Sato Y, Hernando AA, Garcia G, Jensen T8, Rivard C, Sanchez-Lozada LG, Roncal C, Lanaspa MA.
- Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Benoit Chassaing, Omry Koren, Julia K. Goodrich, Angela C. Poole, Shanthi Srinivasan, Ruth E. Ley & Andrew T. Gewirtz. Nature volume 519, pages 92–96 05 March 2015.
- A sequestrant is a food additive which improves the quality and stability of foods. A sequestrant forms chelate complexes with polyvalent metal ions, especially copper, iron and nickel, which can prevent the oxidation of the fats in the food. Sequestrants are a type of preservative.
- Extrusion is is a process by which a set of mixed ingredients are forced through an opening in a perforated plate or die with a design specific to the food, and is then cut to a specified size by blades.
- Don’t Be Fooled – Salt Can Kill You
- Three Reasons Why Sugar May Make Us Ill
- Olive Oil Injures Endothelial Cells
- Animal Foods Are The Smoking Gun
- Nutrients in Plant and Animal Foods
- Food Processing & Preserving Causes Cancer
- UK eats almost four times more packaged food than fresh. The Guardian.
- BMJ talk medicine: “We don’t really know the impact of these products on our health”: Ultraprocessed food & cancer risk