Ultra-processed foods linked to early death

Three cooked sausages on a white background

Research has found a link between eating ultra-processed foods and increased cardiovascular disease and early death. We look behind the headlines.

People who frequently eat more heavily processed foods such as breakfast cereals, sliced bread, ice cream, biscuits and sausages are more likely to develop heart or circulatory disease, and to die, than those who eat less, according to new research.

Two studies on ultra-processed foods were published in the British Medical Journal; one following 105,159 people in France, and another following 19,899 university graduates in Spain.

What are ultra-processed foods?

The studies used the NOVA food classification system to determine how many ultra-processed foods participants were eating. This separates food into four categories based on how much they have been processed during their production: unprocessed or minimally processed; processed culinary ingredients, processed foods; and ultra-processed foods. 

Unprocessed foods include fruit, vegetables, eggs, meat and grains, whereas ultra-processed foods typically have five or more ingredients and contain industrial substances such as preservatives, emulsifiers, sweeteners, and artificial colours and flavours. Examples of ultra-processed foods include ice cream, ham, sausages, crisps, mass-produced bread, breakfast cereals, biscuits, carbonated drinks, fruit-flavoured yogurts, instant soups, and some alcoholic drinks including whisky, gin, and rum. 

Unprocessed or minimally processed foods Fruit, vegetables, eggs, meat and grains
Processed culinary ingredients Sugar, salt, butter, lard, oils, vinegar
Processed foods
Freshly made, unpackaged bread, tinned fruits and vegetables, salted nuts, ham, bacon, tinned fish, cheese and unpackaged freshly made bread 
Ultra processed Ice cream, ham, sausages, crisps, mass-produced bread, breakfast cereals, biscuits, carbonated drinks, fruit-flavoured yogurts, instant soups, and some alcoholic drinks including whisky, gin, and rum. 

The research

Two studies on ultra-processed foods were published in the British Medical Journal; one following 105,159 people in France, and another following 19,899 university graduates in Spain.

Both studies collected detailed information about the foods people ate at the start of the study. Participants in the French study also provided information about their diet on other occasions in the next two years. 

Participants were split into four groups according to their consumption of ultra-processed foods. 

In the Spanish study, the group eating the fewest ultra-processed foods ate less than two servings per day, and the group eating the most ate more than four servings per day. People in the group eating the most ultra-processed foods were 62 per cent more likely to have died after an average of 10.4 years than people in the low consumption group. 

In the French study, participants were classed according to the percentage of their daily diet that came from ultra-processed foods. This ranged from an average of 7.5 per cent for the lowest consumers to 30.8 per cent for the highest. After an average of 5.2 years, each 10 per cent increase in the intake of ultra-processed foods was linked to a 12 per cent increase in cases of heart and circulatory disease. 

How good was the research? 

Both studies were observational, meaning they can only find associations between factors. They can’t prove that ultra-processed foods were the direct cause of increased heart and circulatory disease and death; it’s possible that other factors could be responsible for the association.

Both studies were observational, meaning they can only find associations between factors.

In both studies, the researchers found the same increased risks after taking into consideration other aspects of people’s diets, such as their saturated fat, salt and sugar intake. This suggests the results were not simply down to the higher fat, salt and sugar levels often found in ultra-processed foods. 

The researchers also took into account factors such as people’s age, sex, body mass index, physical activity, smoking status, alcohol intake, calorie intake and family history of heart or circulatory disease. However, other unknown factors linked to an unhealthy lifestyle could be having an effect.

A limitation of both of the studies is that their participants were relatively young. The average ages of participants at the beginning of the studies were 42.7 (French) and 37.6 (Spanish). This meant that only a small proportion of people had developed heart or circulatory disease or died by the end of the study.

Generally speaking, this makes it harder to be certain that any differences in disease and death rates between groups is not due to chance. 

The BHF view

BHF Senior Dietitian Victoria Taylor said: “It’s important to remember that observational studies like these can only show an association. They cannot tell us what is behind this. The classification of ultra-processed foods used by the researchers is very broad and so there could be a number of reasons why these foods are being linked to increased risk to our health, for example nutritional content, additives in food or other factors in a person’s life. Before we consider making any changes to advice or policy it is important to understand this thoroughly." 

There could be a number of reasons why these foods are being linked to increased risk to our health

"We already recommend people adopt a Mediterranean-style diet, which includes plenty of minimally or unprocessed foods such as fruit, vegetables, fish, nuts and seeds, beans, lentils and wholegrains. This, along with exercising regularly and not smoking, has been shown to be beneficial for lowering risk of heart and circulatory disease.”

How the research was reported

The Daily Mail warned that eating highly-processed foods raises the risk of a heart attack or stroke. However it’s not possible to say if ultra-processed foods were the direct cause of the increase in heart and circulatory disease seen in the French study.

The Telegraph quoted the researchers as saying that “modern lifestyles meant up to 60 per cent of daily energy intake was now coming from factory-produced foods.” However the estimate of 25 to 60 per cent given by the researchers was specific to ultra-processed foods, and not all factory-produced foods are classed as ultra-processed. For instance, bacon, cheese, beer and wine are classed as processed foods. 

In another example of confusion about what counts as ultra-processed food, The Independent wrongly suggested that the studies focussed on “foods which contain high levels of added fat and sugar”, however this isn’t true of all ultra-processed foods, such as instant soups, factory-made bread and breakfast cereals.

The coverage highlighted confusion about the difference between processed and ultra-processed foods. Some processed foods, such as bacon and cheese, might seem like less healthy choices than some ultra-processed foods, such as breakfast cereals, factory-made bread and some yoghurts. Neither of the studies assessed people’s consumption of processed foods, so we don’t know whether ultra-processed foods are associated with worse outcomes than processed foods.  

Researchers have suggested that the additives found in ultra-processed foods might be harmful to health, but clearer evidence about these effects would be needed before changes in nutrition guidelines could be made.

 

 

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