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Eating ultra-processed foods such as mass-produced bread, breakfast cereal, ham, crisps and ice-cream could increase the risk of cancer, a study found.
Those who ate the most ultra-processed foods had the highest risk of developing all types of cancer, according to research from Imperial College London.
They were also more likely to die from cancer if they did get it, with breast and ovarian cancers up to a third more (30 per cent) more deadly.
Experts believe chemicals, colourings, sweeteners and preservatives to extend shelf-life could raise the risk, while the relationship between obesity and cancer is already well-established.
Nutritionists split food into three groups based on the amount of processing they have gone through. Minimally processed foods, like apples, are usually exactly how they appear in nature. Processed foods, like apple sauce, have gone through at least one level of processing that has changed their original form. In contrast, ultraprocessed foods like apple jelly babies, have gone through multiple levels of processing and are usually full of extra fats, colours and preservatives
Although based on observational data so not yet proven, they urged people to cut down now or risk ‘serious health problems in the future’ and called for warnings to be put on packaging.
Britons lead Europe when it comes to ultra-processed foods, with the average adult consuming half of their daily calories from these foods – rising to 65 per cent in children.
The study, funded by Cancer Research UK and the World Cancer Research Fund, used UK Biobank data to examine the diets of 197,426 people aged 40 to 69, tracking their health over a decade.
They measured the amount consumed in both grams and calorie intake, finding those who ate the most had a greater risk of developing cancer overall, and specifically ovarian cancer.
The researchers found that for every 10 per cent increase in ultra-processed food in a person’s diet, there was a 2 per cent increased risk of cancer overall, and a 19 per cent increased risk for ovarian cancer specifically.
Cancers of the stomach, bowel, oesophagus, liver, lung, kidney and thyroid all increased, the research showed.
Each 10 per cent rise was also associated with a 6 per cent increased risk of dying from cancer, with a 16 per cent increased risk for breast cancer and a 30 per cent increased risk for ovarian cancer.
These links held true even after adjusting for factors that may alter the results, such as exercise, body mass index (BMI) and deprivation, according to the findings published in eClinicalMedicine.
Those who ate the most – accounting for 41 per cent of food intake measured by weight and more than half of their daily calories – had a seven per cent higher risk of cancer overall than those who ate the least.
Dr Kiara Chang, of Imperial College London, said the industry had boomed over the past 50 years but regulations have failed to keep pace.
She said: ‘The average person in the UK consumes more than half of their daily energy intake from ultra-processed foods.
‘This is exceptionally high and concerning as ultra-processed foods are produced with industrially derived ingredients and often use food additives to adjust colour, flavour, 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.’
Shop-bought mass-produced bread, ready meals, various breakfast cereals, reconstituted meat products such as ham, sweets, and shop-bought biscuits, buns and cakes are among the most commonly eaten ultra-processed foods in the UK.
The young and those on lower incomes are at particular risk, she warned, with cheap prices and aggressive marketing making them particularly attractive.
The switch to convenience foods mean people tend to pay less attention to what they are eating, with foods typically high in fat, salt and sugar with additional chemicals, colourings, sweeteners and preservatives to extend shelf-life.
She added: ‘This shows our food environment needs urgent reform to protect the population from 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.’
Previous studies have suggested a link between ultra-processed foods and heart disease, as well as obesity and type 2 diabetes.
The authors said that although the study cannot prove causation, other available evidence shows that reducing ultra-processed foods in our diet could provide important health benefits.
Dr Panagiota Mitrou, director of research and innovation at the World Cancer Research Fund, said: ‘The findings in this first UK study of its kind are significant as this is the most comprehensive assessment of ultra-processed foods and cancer risk.
‘This adds to the growing evidence linking these foods to cancer and other health conditions.’
A Department of Health and Social Care spokesperson said: ‘A diet high in processed foods is often high in calories, salt, saturated fat and sugar and low in fibre which is associated with an increased risk of developing chronic diseases including some cancers. We therefore encourage everyone to have a healthy balanced diet in line with the UK’s healthy eating model the Eatwell Guide.
‘The NHS Food Scanner app also helps families to see what’s in their food and drinks and gives choices of products that can help them cut down on sugar, saturated fat and salt.’