# Dietary vitamin B9 intake linked to drug-resistant epilepsy risk in western Chinese adults: exploring underlying metabolomic mechanisms

## TL;DR

Higher vitamin B9 intake is linked to lower risk of drug-resistant epilepsy in Chinese adults, with metabolomic insights into underlying mechanisms.

## Contribution

Identifies dietary vitamin B9 as a novel risk factor for drug-resistant epilepsy and provides metabolomic evidence for its role.

## Key findings

- Dietary vitamin B9 intake was inversely associated with drug-resistant epilepsy risk (OR: 0.78 per 100 μg).
- Metabolomic analysis revealed altered linoleic acid metabolism, cortisol levels, and folate pathways in drug-resistant epilepsy.
- The protective effect of vitamin B9 remained consistent across subgroups with no significant interactions.

## Abstract

Approximately 30% of epilepsy patients develop drug-resistant epilepsy (DRE), underscoring the need for adjunctive therapies. While dietary interventions like the ketogenic diet show promise, evidence for specific micronutrients, particularly regarding differences between DRE and non-drug-resistant epilepsy (NRE), remains scarce. This study investigated B-vitamin intake and plasma metabolomic profiles in NRE versus DRE patients.

We established a cohort of 330 adults with epilepsy (165 NRE, 165 DRE) from western China. Dietary intake of vitamins B1, B6, B9, and B12 was assessed. Multivariate logistic regression and restricted cubic splines (RCS) analyzed associations between vitamin intake and DRE risk. Stratified analyses evaluated consistency across subgroups. Untargeted metabolomics was performed on a subset of patients to identify differential metabolites and pathways.

In the fully adjusted model, only dietary vitamin B9 (folate) intake was significantly and inversely associated with DRE risk (OR: 0.78 per 100 μg, 95% CI: 0.64–0.94; p = 0.01). The RCS indicated a linear dose-response relationship (non-linearity p = 0.412). This protective association remained stable across various subgroups without significant interactions. Metabolomic analysis revealed distinct profiles between NRE and DRE, identifying key differential metabolites including decreased linoleic acid and tetrahydrofolyl-glutamate, and increased cortisol. Pathway analysis implicated alterations in linoleic acid metabolism, cortisol synthesis and secretion, and folate metabolism.

This study identifies lower dietary vitamin B9 intake as an independent risk factor for DRE in a Chinese adult cohort, with each 100 μg increase conferring a 22% reduction in risk. The metabolomic findings provide potential mechanistic insights, linking folate intake to dysregulated stress hormone, inflammatory, and one-carbon metabolism pathways in DRE. These results highlight the potential of nutritional assessment and intervention in the management of drug-resistant epilepsy.