A groundbreaking study published in PLOS Medicine suggests that blood and urine samples can offer valuable insights into an individual’s diet, particularly their consumption of ultra-processed foods. These samples may provide an objective measure of dietary habits and shed light on the potential links between diet and various diseases such as diabetes and cancer.
Ultra-processed foods are defined as industrially manufactured products that often contain additives and ingredients not commonly found in homemade meals. From sugary snacks to pre-packaged meals, these foods have been associated with a range of health conditions including obesity, cardiovascular disease, and certain types of cancer. Traditional methods of assessing diet, such as self-reported food intake, can be unreliable. However, the analysis of metabolites in blood and urine samples presents a promising alternative.
The study, led by epidemiologist Erikka Loftfield from the US National Cancer Institute, involved analyzing samples from 718 healthy individuals aged 50–74. Participants provided urine and blood samples twice over a six-month period, while also recording their daily food intake up to six times within a year. Each food item was categorized as either ultra-processed or unprocessed, and a machine-learning algorithm was used to calculate the percentage of energy derived from ultra-processed foods in each participant’s diet.
On average, ultra-processed foods accounted for 50% of participants’ energy intake, with individual variations ranging from 12% to 82%. Those consuming higher levels of ultra-processed foods tended to have diets higher in carbohydrates, added sugars, and saturated fats, and lower in proteins and fiber. Analysis of blood and urine samples revealed specific metabolites associated with diets rich in ultra-processed foods, including markers linked to type-2 diabetes risk and molecules derived from food packaging.
In a separate randomized controlled study involving 20 individuals aged 18–50, researchers successfully distinguished between diets rich in ultra-processed foods and those free of such products by examining metabolites in blood and urine samples. This innovative approach shows promise for further research on the impact of ultra-processed foods on health outcomes, particularly in diverse populations and younger age groups.
Moving forward, Loftfield aims to expand the application of this method to broader populations with varying diets, with a focus on improving our understanding of the relationship between ultra-processed foods and cancer. Molecular epidemiologist Oliver Robinson highlights the potential of this tool in addressing critical questions about the health effects of ultra-processed foods and guiding improvements in food production practices.
This study, published in 2025, underscores the importance of objective measures in assessing dietary patterns and their implications for health. By leveraging the analysis of blood and urine samples, researchers are paving the way for a more nuanced understanding of the impact of ultra-processed foods on our well-being.
