Background: Plant-based diets are not inherently healthy. Similar to omnivorous diets, they may contain excessive amounts of sugar, sodium, and saturated fats, or lack diversity. Moreover, vegans might be at risk of inadequate intake of certain vitamins and minerals commonly found in foods that they avoid. We developed the VEGANScreener, a tool designed to assess the diet quality of vegans in Europe. Methods: Our approach combined best practices in developing diet quality metrics with scale development approaches and involved the following: (a) narrative literature synthesis, (b) evidence evaluation by an international panel of experts, and (c) translation of evidence into a diet screener. We employed a modified Delphi technique to gather opinions from an international expert panel. Results: Twenty-five experts in the fields of nutrition, epidemiology, preventive medicine, and diet assessment participated in the first round, and nineteen participated in the subsequent round. Initially, these experts provided feedback on a pool of 38 proposed items from the literature review. Consequently, 35 revised items, with 17 having multiple versions, were suggested for further consideration. In the second round, 29 items were retained, and any residual issues were addressed in the final consensus meeting. The ultimate screener draft encompassed 29 questions, with 17 focusing on foods and nutrients to promote, and 12 addressing foods and nutrients to limit. The screener contained 24 food-based and 5 nutrient-based questions. Conclusions: We elucidated the development process of the VEGANScreener, a novel diet quality screener for vegans. Future endeavors involve contrasting the VEGANScreener against benchmark diet assessment methodologies and nutritional biomarkers and testing its acceptance. Once validated, this instrument holds potential for deployment as a self-assessment application for vegans and as a preliminary dietary screening and counseling tool in healthcare settings.

Background and Objectives: Consumption of plant-based diets, including vegan diets, requires attention towards diet quality and the early detection and prevention of nutritional deficiencies. The VEGANScreener project aims to develop and validate a standardized brief web- and app-based screening tool to assess and monitor diet quality among vegans in Europe. To this end, a clinical study will be performed to evaluate the VEGANScreener against a reference diet assessment method and nutritional biomarkers. Materials and Methods: An observational cross-sectional study will comprise six hundred participants across four European sites (Germany, Spain, Belgium, Czech Republic): 400 self-reported vegans (≥2 years on vegan diet) and 200 self-reported omnivore controls; without diseases affecting the metabolism and intestinal integrity; aged 18 to 65 years (1:1 ratio 18–35 and 36–65); males and females (1:1 ratio). Subjects will be enrolled after an online eligibility check. Informed consent will be obtained, and the subjects enrolled will be given a unique ID (pseudonymized). The initial clinical visit consists of structured medical history-taking, blood pressure, heart rate and anthropometric measurements, blood, spot urine and saliva sampling, distributing the VEGANScreener access, diet record instructions, and general survey access. A follow-up collection visit will be scheduled 14–21 days apart: 24 h urine and 4-day diet records will be collected, and subjects’ participation will be terminated. VEGANScreener will be administered twice to limit the within- person errors. Results: Field work is ongoing, and we expect to have results by the time of the conference. Discussion: The VEGANScreener tool will be validated for the target population. The primary objective is to assess the construct validity and criterion validity of the VEGANScreener through associations of the score with nutrient intakes from a 4-day diet record and associations with biomarkers of dietary intake. Standard statistical models will be implemented for cross-sectional comparisons of geographical groups. Secondary outcomes will include analyses of dietary data and metabolomics. Vegan subgroups will be identified with dimensionality reduction methods and univariable statistical tests. Major nutrient sources and variations across groups will be assessed. Exploratory metabolomic analysis (blood, urine, saliva) to identify novel concentration biomarkers of dietary intake and nutritional adequacy will be performed using multivariable analysis.

Background and objectives: Diet is one of the fundamental factors that not only determines metabolic health but also shapes the gut microbiome and serum metabolome (MIME). Plant-based diets are associated with potential health benefits, but their effect on MIME remain to be elucidated. We sought to determine whether diet-dependent markers explaining the observed health benefits of a vegan diet could be identified in the MIME of vegans from different geographic regions. Methods: Lean, healthy vegans (n = 100) and omnivores (n = 73) with comparable BMI from two geographical regions (Czech Republic, Northern Italy) participated in the cross-sectional study. Based on their clinical characteristics and serum markers, we investigated their glucose and lipid metabolism and used an integrated multi-omics approach (16S rRNA sequencing, metabolomics and lipidomics profiling) to identify country- and diet-specific MIME markers. Results: Czech and Italian vegans exhibited more favorable lipid profile parameters compared to omnivores characterized by decreased serum concentrations of sphingomyelins, ceramides, cholesterol esters, and lipid species containing saturated fatty acid. Using a machine learning approach, we were able to discriminate between vegans and omnivores based on separate omics datasets, regardless of country of origin. By combining all MIME features, we were able to identify a vegan diet-specific multi-omics signature that allows for the classification of vegans and omnivores with high accuracy. Most of the vegan-specific variables were associated with favorable indices of lipid and glucose metabolism, inflammation, or body weight. Discussion: Most of the MIME markers that are down-regulated in vegans are predominantly associated with adverse health outcomes, whereas those that are up-regulated are associated with a healthy phenotype and a low risk of non-communicable diseases. Our findings support the potential use of a healthy plant-based diet in the treatment of metabolic disorders.