People who consume large amounts of ultra-processed food may develop an unhealthy pattern of fats and other metabolites in their blood, according to a large European study offering new clues about how highly processed diets may contribute to chronic disease.
Researchers found that participants with higher consumption of ultra-processed foods had increased levels of industrial trans fats, certain saturated fats and other compounds associated with poor fatty-acid processing.
At the same time, they had lower levels of beneficial fats, including the omega-3 fatty acid docosahexaenoic acid, commonly known as DHA, which plays an important role in brain function, cardiovascular health and cell structure.
The findings add biological evidence to previous research connecting ultra-processed food consumption with obesity, type 2 diabetes, cardiovascular disease and other health problems.
Ultra-processed foods are industrially manufactured products that often contain flavourings, colourings, emulsifiers, preservatives and other additives. They typically contain high amounts of sugar, salt, refined carbohydrates, unhealthy fats and energy.
Common examples include soft drinks, packaged sweet and savoury snacks, reconstituted meat products, instant meals and many ready-to-eat frozen foods.
Although previous research has repeatedly associated these products with poorer health, scientists are still working to understand the biological mechanisms responsible for those outcomes.
The latest study suggests that ultra-processed foods may affect more than the amount of fat directly absorbed from meals. They may also encourage the body to manufacture additional fats from excess carbohydrates while interfering with the normal processing and use of lipids.
The research was based on information collected through the European Prospective Investigation into Cancer and Nutrition, commonly known as the EPIC study.
The wider EPIC project recruited more than 520,000 volunteers from Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Spain, Sweden and the United Kingdom between 1992 and 2000.
Most participants were between 35 and 70 years old when they entered the study, and women represented approximately two-thirds of the group.
Participants completed detailed questionnaires covering their lifestyles and food consumption during the previous year. Some also completed 24-hour dietary records, while researchers collected blood samples and physical measurements.
For the latest analysis, scientists examined dietary information from more than 15,200 people and compared their ultra-processed food consumption with metabolites found in their blood.
Foods were classified using the NOVA system, which divides products into four categories based on the level and purpose of processing.
The first category includes fresh or minimally processed foods such as vegetables, fruit, legumes, eggs, fish, milk and meat.
The second covers culinary ingredients used in food preparation, including oils, butter, sugar and salt.
The third group includes processed foods such as cheese, freshly made bread, canned vegetables, canned fish and fruit preserved in syrup.
The fourth category contains ultra-processed products manufactured through multiple industrial processes and commonly formulated with additives to improve flavour, appearance, texture or shelf life.
Researchers measured ultra-processed food intake by weight rather than by calories. This approach allowed them to include low-calorie or calorie-free drinks and other products that could represent a substantial part of a person’s diet without contributing many calories.
The participants’ median ultra-processed food intake was approximately 12.6 per cent of their overall diet, although individual consumption varied considerably.
Scientists identified a distinct metabolic pattern among participants who consumed the largest quantities of these foods.
They had higher levels of certain lipid derivatives associated with impaired fatty-acid oxidation and mitochondrial dysfunction. Mitochondria are structures within cells that help convert nutrients into usable energy.
The same participants also had lower levels of several fats that support cell-membrane stability, permeability and communication between cells.
Lead researcher Jessica Blanco-López said the results provided biological support for the growing body of research linking ultra-processed diets with poorer health.
She said one of the most important findings was the combination of reduced beneficial omega-3 fats and increased omega-6 fatty acids, industrial trans fats and other compounds linked to disrupted lipid metabolism.
Researchers also found changes in metabolites involved in energy production, suggesting that diets high in ultra-processed foods may disturb the body’s normal balance of fats and energy.
Independent physician-scientist Thomas M. Holland said the findings went beyond simply observing that people who eat more ultra-processed food experience higher rates of disease.
The study identified measurable biological differences that could help explain why those dietary patterns are repeatedly associated with poor health outcomes.
Higher levels of industrial trans fats and certain saturated fats are important because the types of fat circulating through the bloodstream can influence cardiovascular, metabolic and neurological health.
Meanwhile, lower levels of DHA and other beneficial fats may negatively affect cell function, inflammation control and the maintenance of the brain and heart.
Researchers said food appears to leave a detectable metabolic “fingerprint” in the human body, with ultra-processed products creating a pattern different from that associated with less processed diets.
However, the scientists cautioned that the research was observational. This means it identified an association between ultra-processed food intake and blood metabolites but could not prove that the foods directly caused the metabolic changes.
Other aspects of participants’ diets, lifestyles or health conditions may have influenced the results.
Several of the fats and metabolites identified in the research have previously been connected with obesity, cardiovascular disease and type 2 diabetes.
The researchers said these compounds could represent early biological changes that may help explain why long-term studies consistently associate high ultra-processed food consumption with chronic illness.
Further research will be needed to determine whether reducing ultra-processed food intake can reverse or improve these metabolic patterns.
Scientists recommended repeating the analysis in populations with different diets and lifestyles, as the latest research focused mainly on European participants recruited several decades ago.
Long-term studies and controlled feeding trials would also help establish whether ultra-processed foods directly cause changes in blood fats and whether those changes eventually contribute to disease.
Researchers said future investigations should also use newer participant groups and broader methods capable of detecting a greater range of metabolites.
Health experts stressed that people do not need to pursue a perfect diet to improve their wellbeing.
Instead, they recommended building a consistent eating pattern centred on minimally processed foods such as vegetables, fruit, legumes, whole grains, fish, eggs, nuts and other basic ingredients.
Regular exercise, sufficient sleep, stress management, avoiding tobacco and maintaining social connections were also identified as important elements of healthy ageing.
The findings suggest that reducing dependence on packaged and heavily processed products may be one practical part of a broader healthy lifestyle.
While more research is required to confirm cause and effect, the study strengthens concerns that ultra-processed foods may influence health by altering the balance of fats and energy-related compounds circulating in the blood.
