In today’s fast-paced world, convenience and cost often guide our food choices which unfortunaely has led to rise in the amount of ultra-processed food we are eating. In fact, one study in the British Medical Journal (BMJ) showed that more than half of the energy (i.e. calories) of a person in the UK comes from ultra-processed foods.
In this article we will delve deeper what are ultra-processed foods, whether there is a difference between processed and ultra-processed foods and answering the big question of whether cancer and processed or Ultra-Processed Foods is linked.
What is ultra-processed or processed food?
The terms ‘processed’ and ultra-processed’ foods are used a lot but what this actually mean?
Processed food
All food has to go through some processing unless you grow everything at home and eat it fresh! The reasons why foods are processed is so they last longer, their flavour is enhanced or it is safer for you to eat. For example, pasteurising, freezing, caning, drying, chopping or cooking is all a form of processing.
Ultra-processed food
This terms comes from researchers at the University of Sao Paulo in Brazil who developed the definition ‘Ultra-processed food’ and the NOVA food classification
The NOVA food classification divides foods into 4 groups depending on how much they have been processed:
1. Unprocessed or minimally processed foods
Foods included: fruit, vegetables, milk, fish, pulses, eggs, nuts and seeds
These foods have no added ingredients and haven’t been changed much from their natural state (e.g. they have removed inedible or unwanted parts of the food)
2. Processed ingredients Foods included: salt, sugar, butter, lard, oils, vinegar
This includes food ingredients that are added to other foods and generally not eaten on their own.
3. Processed foods
Foods included: homemade jam, pickles, tinned fruit and vegetables, homemade breads and cheeses.
These are foods that are made by combining foods from groups 1 and 2, which are changed in a way that you could do at home yourself.
4. Ultra-processed foods Foods included: breakfast cereals, biscuits, fizzy drinks, fruit-flavoured yoghurts, instant soups, ham, ice cream, sausages, mass-produced bread, hot dogs, some alcoholic drinks (gin, rum, whiskey) Ultra-processed foods usually have five or more ingredients. They tend to include additives and ingredients that are not typically used in home cooking, for example preservatives, emulsifiers, sweeteners, and artificial colours and flavours. These foods generally have a long shelf life.
What do you need to know about cancer and processed or ultra-processed foods?
So what about cancer and processed food or ultra-processed foods. Should you be swapping these out of your diet? Research has been looking at if there is a link between processed and ultra-processed foods and cancer and you may have seen the headlines.
A few studies in 2023 looked at the risk of cancer and ultra processed foods and found that people who ate 10% more of these foods had a 19% increased risk of ovarian cancer and 2% overall greater risk of cancer 1.
Another study in 2023 showed that people who replaced 10% of ultra-processed foods with minimal processed food was linked to reduction on 7 types of cancer 2.
There was a large study published last year in 2024, which explored the connection between processed food and breast cancer risk 3.This is a really interesting study which followed over 300,000 women across nine European countries for nearly 15 years. It used the data from the European Prospective Investigation into Cancer and Nutrition (EPIC) study. They collected information on the diet of the people in the study and grouped food intake into four categories using the NOVA classification system described above. When they looked at food intake and risk of breast cancer there was no significant link between unprocessed, culinary ingredients, or ultra-processed foods and breast cancer.
There was a small link between processed foods (NOVA 3) and breast cancer—but only if they included alcohol intake in the results. So it turns out, this connection was likely driven by alcoholic drinks included in the processed food category.
There is already strong evidence that processed meats are linked with bowel cancer. Processed meats include meats that are smoked, cured or had salt or chemical preservatives added (e.g. bacon, salami, chorizo, corned beef, pepperoni, pastrami, hot dogs and ham). So, these should be avoided. if you are interested in reading more about this you can read here .
However, these studies don’t tell us whether processed and ultra processed food is directly linked to an increased cancer risk. Like many studies in diet and health, these were observational studies and doesn’t show that an ultra-processed diet causes cancer. If you look deeper in research you also see that the people studied had a low intake of vegetables and other healthier foods such as pulses, nuts, seeds and fruit. So, it is very difficult to say whether ultra-processed foods were associated with increased cancer risk or that it was because their diet overall was unhealthy.
Are there any other health risks of ultra-processed foods?
Weight gain
A lot of processed or ultra-processed foods, are high in fat, sugar and salt and low in fibre. It is commonly known that eating high fat and sugar foods can lead to weight gain which increases the risk of type 2 diabetes, heart problems and some cancers.
Also, there is some research into how our bodies respond to food depending on how they are processed. For example studies have shown that when you eat whole nuts you absorb less fat compared to when the nuts are ground and their oils are released. But what we do know is that processed and ultra-processed foods can cause excess weight gain and obesity and obesity is linked to increased risk of 13 different types of cancer 4.
Gut health
As some of these foods are also low in fibre they may negatively affect your gut health as fibre is needed to keep you gut bacteria healthy.
Does ultra-processed foods have any nutritional benefits?
The less obvious types of ultra-processed foods are foods like low sugar wholegrain breakfast cereals, shop bought sliced wholemeal bread, baked beans and even home-made bread could be classed as ultra-processed with it was made from fortified flour! These types of foods have other benefits as they may have added vitamins and minerals and a good source of fibre so can be actually eaten as part of a healthy diet. This is where ultra-processed foods become confusing as not all ultra-processed foods are unhealthy as we seen above.
What is the cancer dietitian verdict?
It is a good idea to limit some of the obviously processed foods and drinks in your diet like sweets, cakes, biscuits, processed meats, and ready meals especially as it is linked to excess weigh gain which does increase the risk of some cancers. But we don’t know if cancer and processed or Ultra-Processed foods is directly linked.
Where you can include fruits and vegetables (tinned, fresh, frozen are all ok), limit red meat (see blog), include protein sources from fish, pulses nuts and seeds. Aim to try to prepare meals yourself too and remember this doesn’t have to be too complicated. Some ideas to try Reduce the biscuits, cakes and sweets- try whole nuts, fruit, seeds instead
Drop the readymade sauces- make your own and freeze so you can use another day (tomato, butternut squash sauces freezes very well)
Swap your flavoured yoghurt- chose plain yoghurt and add your own fruit!
If you would like help planning your diet, and swapping to less ultra-processed food my programmes all include a dietary analysis so you can see exactly if you are getting the right amount of nutrients and we can develop a plan to create a healthy diet together!
References:
1 https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(23)00017-2/fulltext
2 https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(23)00021-9/fulltext
3 https://fppn.biomedcentral.com/articles/10.1186/s43014-024-00264-2
4 https://www.wcrf.org/preventing-cancer/topics/weight-and-cancer/
