Researchers have developed a new way to measure how much ultra-processed food (UPF) a person eats by analyzing their blood and urine, according to a new study published in PLOS Medicine. This method could help improve how scientists study diet and disease.
Background
Ultra-processed foods like chips, sugary drinks, and ready-made meals now make up more than half of the daily calories for many Americans. These foods are made mostly from refined ingredients and additives and are linked to serious health problems, including obesity, heart disease, type 2 diabetes, and some cancers.
Until now, most studies relied on self-reported food surveys to measure UPF intake. But these are not always accurate. Researchers are now using metabolomics—a technique that looks at small molecules in the body—to find clear, biological markers that reflect a person’s diet.
The Study
The study used data from 718 adults aged 50 to 74 in the United States. Participants completed multiple online food recalls over a year. Researchers used the NOVA food classification system to estimate how much of each person’s diet came from UPFs.
Blood and urine samples were collected at two time points, six months apart. These samples were tested for over 1,000 types of molecules. The researchers then used advanced statistical methods to find patterns that matched high or low UPF intake. They created “poly-metabolite scores”—groups of biomarkers that predict how much UPF a person has eaten.
Confirming the Results
To test their findings, the team used data from a separate feeding trial with 20 adults who followed two different diets—one with 80% UPF and another with no UPF—for two weeks each. Blood and urine samples from both diet periods were analyzed to see if the poly-metabolite scores could accurately reflect dietary changes. The results showed the scores reliably tracked UPF intake.
Key Findings
Researchers identified hundreds of metabolites in blood and urine linked to UPF consumption. Among the most reliable markers were:
- N6-carboxymethyllysine – linked to higher UPF intake and associated with heart disease and diabetes.
- β-cryptoxanthin – lower levels found in people who ate more UPFs, suggesting fewer fruits and vegetables in their diet.
- Several compounds from food packaging and additives were also more common in people eating more UPFs.
These markers showed that high UPF diets are not only low in nutrients but may also introduce harmful chemicals into the body.
Implications for Health
The new method offers a more accurate way to track UPF intake using biological samples, helping researchers study links between diet and disease. However, the study focused mostly on older, White adults, so more research is needed in diverse and younger populations. Also, the feeding trial sample was small and not designed to track long-term health outcomes.
Conclusion
This study is a major step toward using blood and urine tests to objectively measure ultra-processed food intake. While more work is needed, these tools could improve nutrition research and public health efforts by giving clearer insights into how diet affects the body.
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