Blood signatures may explain about half of ultra-processed food’s link to heart disease and diabetes, study finds
Researchers at UCL and Imperial College London have identified blood molecule patterns for ultra-processed and minimally processed diets that may explain roughly half of the link between such diets and later heart disease and type 2 diabetes.
Scientists have identified two distinct patterns of molecules in the blood — one associated with a diet high in ultra-processed food and the other with a minimally processed diet — which together may explain roughly half of the observed link between these diets and later heart disease and type 2 diabetes. The study, by researchers at UCL and Imperial College London, was published in the journal BMC Medicine and reported on 3 November.
The work drew on data from more than 6,000 adults in the United Kingdom who gave blood samples and completed questionnaires about what they ate, and whose health was then followed for up to 20 years. The participants came from the Whitehall II study, a long-running cohort of British civil servants first recruited in the 1980s and tracked for decades since.
The team measured 233 metabolites — small molecules produced as the body processes food and carries out its chemistry — using nuclear magnetic resonance spectroscopy. With the help of machine learning, they identified the molecules most closely tied to each way of eating: 34 metabolites formed the signature of an ultra-processed diet and 50 formed the signature of a minimally processed one, with eight appearing in both.
The ultra-processed signature was characterised by lower levels of omega-3 fatty acids and of HDL, often called “good” cholesterol, alongside higher levels of triglycerides carried by very-low-density lipoproteins — the kind of blood fats that, in excess, contribute to clogged arteries. The minimally processed signature pointed in the opposite direction.
Each participant was given a score for how closely their blood pattern matched each dietary signature, and those scores were compared with later disease. The metabolite profile for ultra-processed food accounted for about 51 per cent of the statistical link with later cardiovascular disease and about 43 per cent of the link with type 2 diabetes.
The underlying risks were substantial over the two decades of follow-up. Participants in the highest third for ultra-processed food intake had a 17 per cent higher risk of developing cardiovascular disease than those in the lowest third, while the third eating the most minimally processed food had a 19 per cent lower risk of cardiovascular disease and a 40 per cent lower risk of type 2 diabetes.
Notably, the diet–disease link remained even after accounting for the sugar, fat and salt typical of ultra-processed diets. Salt and saturated fat did not appear to explain the risks, and sugar accounted for only part of the diabetes link, an estimated 27 per cent. Lead author Dr Eunice Wang said the findings hint that processing itself may play a role, while stressing that more research is needed to support that idea.
The unexplained half of the link, the researchers suggest, might run through pathways the blood measures do not capture — influences on gut microbes, on inflammation in the body, or on the appetite and fullness signals that shape how much people eat. Those possibilities are now among the questions the team’s work raises for follow-up studies.
The findings land in the middle of a live policy debate. Current United Kingdom dietary guidance does not treat processing itself as a risk factor, instead recommending lower intakes of foods high in sugar, salt and saturated fat, and the government’s Scientific Advisory Committee on Nutrition is currently weighing the evidence on ultra-processed foods. Senior author Professor Clare Llewellyn said the study, the first to compare the metabolic signatures of the two diets directly, adds evidence for future discussions about whether the degree of processing should be considered alongside a food’s nutritional profile.
The authors are careful about the limits of their design. Because this was an observational study, it cannot prove that ultra-processed food causes the diseases, however long the follow-up — a strength the team notes is greater than in many similar studies. The next tests of the idea may come from controlled feeding trials and from more diverse populations, which could show whether changing the level of processing in a diet changes the blood signature itself, and whether risk follows.
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