# Assessing Choline, Carnitine, and Betaine Intake and Their Effects on Trimethylamine N-Oxide Levels: Validation of a Dietary Questionnaire in a Central European Population

## TL;DR

This study developed and validated a dietary questionnaire to assess intake of TMAO precursors like choline, carnitine, and betaine in a Central European population.

## Contribution

The study introduces a validated dietary tool to evaluate TMAO precursor intake for cardiovascular risk assessment.

## Key findings

- The questionnaire identified three main dietary factors influencing TMAO levels: fish and legumes, cereals and root vegetables, and meat.
- The tool showed acceptable data quality and reliability for assessing TMAO precursor consumption.
- The questionnaire is useful for dietary risk assessment and counseling in post-myocardial infarction patients.

## Abstract

Background/Objectives: Trimethylamine N-oxide (TMAO) is implicated in the development of atherosclerosis and cardiovascular diseases. Preventive strategies must recognize the excessive consumption of products rich in choline, carnitine, and betaine, which are substrates essential for TMAO synthesis. The aim of this study was to develop and validate a dietary questionnaire to assess the consumption of these compounds and investigate the correlation with serum TMAO levels in a Central European population. Methods: A dietary questionnaire was designed based on a literature review identifying foods high in TMAO precursors. The tool was validated in a prospective study with 94 participants. The theoretical relevance and reliability of the tool were assessed using factor analysis and statistical indices. Reproducibility was evaluated in a subgroup of 10 participants who completed the questionnaire a second time 24 h later. The results of the questionnaire helped us to determine factors contributing to serum TMAO levels. Results: The final questionnaire consisted of 15 questions, providing acceptable data quality (KMO = 0.654). Three main dietary factors were detected: (1) the consumption of fish products and legumes (SS loadings = 1.72; 10.78% variance), (2) the consumption of cereal products and root vegetables (SS loadings = 1.61; 10.05% variance), and (3) the consumption of meat (SS loadings = 1.47; 9.22% variance). Conclusions: The validated questionnaire is a useful tool for assessing the intake of TMAO-promoting foods in post-myocardial infarction patients from Central Europe. It may support dietary risk assessment and nutritional counseling in clinical practice, particularly for secondary cardiovascular prevention.