A daily bag of crisps or can of fizzy drink — often bundled in supermarket meal deals — is linked to a 14% increase in heart attacks and strokes. The finding comes from the largest ever review of ultra processed foods (UPFs), covering studies involving 8.8 million people, which also suggests these products raise the risk of early death.
People who consumed a lot of UPFs faced a 24% higher risk of cardiovascular events, and every extra 100g daily portion on average increased the risk by 14%. A typical 100g UPF portion includes items such as a cheap yogurt, a bag of crisps, a box of six chicken nuggets, a pre-made supermarket sandwich or wrap, and a can of fizzy drink. Many of these options appear in popular supermarket meal deals, which office workers consume daily.
Risks across multiple conditions
Researchers reviewed 51 studies spanning two to 32 years and found participants who ate a lot of UPFs were at 18% higher risk of death from any cause. They were at 31% higher risk of digestive conditions such as inflammatory bowel disease and irritable bowel syndrome, 27% higher risk of depression and anxiety, 12% higher risk of cancer, and 11% increased risk of high blood pressure.
UPFs are defined as ready-to-eat or heat-and-serve products that have undergone extensive industrial processing. They tend to contain preservatives, emulsifiers, and artificial colours and flavours which could be bad for health. Examples include mass produced supermarket sliced bread, instant noodles, formed ham, breakfast cereals, and ice cream.
Possible mechanisms and expert caution
The researchers highlighted emerging evidence that the combination of multiple additives may exert a ‘cocktail effect’ on human health. Lab studies have shown that UPFs may harm the gut microbiome as well as promote inflammation and insulin resistance. Compounds such as acrylamide, formed in heat-treated processed foods, and acrolein, generated during fat heating, have been linked to developing cardiovascular disease.
The team collated studies from America, Europe, Asia, and Oceania involving 8,819,894 participants aged from 23 to 77. UPF consumption was assessed by food frequency questionnaires and 24-hour dietary recall. Analysis showed that each extra 100g per day consumed was associated with 4% greater risk of cancer, 3% of death from any cause, and 2% of developing Type 2 diabetes.
Commenting on the research, Gunter Kuhnle, professor of food science at Reading University, said: “Measuring food intake is notoriously difficult, as people are often not very good at remembering what they ate. Estimating UPF intake from these data is even more difficult for several reasons.” He noted that assessment methods may simply record ‘bread’, failing to distinguish artisan from supermarket bread, meaning observational studies rely on very unreliable data.
Another factor making it difficult for researchers to tease out possible health harms of UPFs is that they also tend to be high in sugar and salt, and low in dietary fibre, protein, vitamins, and minerals. Prof Kuhnle added: “Some trials show that adherence to dietary recommendations is more important than whether food is processed or ultra processed. It is therefore important to encourage the general public to follow current dietary recommendations.”
Tracy Parker, nutrition lead at the British Heart Foundation, said: “We don’t currently have enough research to understand whether there is something specific within UPFs which causes these issues, like food additives, or whether the processing of the food itself alters the way our bodies respond to it. But we do know that UPFs are often high in salt, sugar and saturated fat, so it’s best to limit the amount you eat.” She suggested cutting back on cakes, biscuits, and ready-made snacks, and cooking more meals from scratch.
The findings are published in the journal Family Medicine and Community Health.
