Accurate information on food intake is necessary to investigate diet-health associations. Traditional assessment methods depend on self-reported data, which are prone to measurement error and bias. Specifically, plant-based foods are frequently misreported. Diets predominantly consisting of plant-based foods are associated with lower risk for non-communicable diseases. However, emerging data indicates that unhealthful plant-based diets are related with raised disease risk.

Therefore, the main objective of PlantIntake is to improve the dietary assessment of plant-based foods by combining self-reported intake data with biomarker data from blood and urine.

Initially, we will derive a “European plant-based diet index” by adapting previously defined plant-based dietary patterns for the European setting, considering aspects of diversity, processing, and the proportion of healthful and unhealthful components. Association of healthful and unhealthful patterns with health outcomes will be assessed such as for type 2 diabetes and cardiovascular disease.

Based on an up-to-date inventory of biomarkers for plant food groups, we will establish a wide-coverage targeted analytical method with >150 biomarkers, which will be applied to samples from at least three European nutrition studies. Based on these data we will develop multi-biomarker panels reflecting the intake of plant food groups and adherence to the European plant-based diet indices. We will examine multiple options for combining the biomarker panels and self-reported data – thus moving the panels closer to uptake by the wider nutrition community. Included in this work will be the development of calibration equations and the development of a “composite intake score” using complementary information from biomarkers and self-reported dietary data.

Finally, we will validate the developed tools and evaluate their potential confounders by applying them to the available studies, and by performing a validation study to analyze the biomarker panels in terms of accuracy, dose-response, sampling time and reproducibility.

Taken together, we expect that the multi-biomarker panels and composite intake score developed in this project will serve as reference tools for the assessment of plant food intake in future studies and will improve our understanding of diet-health associations enabling more reliable dietary recommendations.