# Serum α-linolenic acid, not intake, associates with reduced arterial stiffness assessed by brachial-ankle pulse wave velocity: an exploratory post hoc analysis of a randomized controlled trial

## TL;DR

Higher levels of serum alpha-linolenic acid (ALA) are linked to reduced arterial stiffness in middle-aged Japanese women, suggesting that ALA in the blood, not dietary intake, may be more important for vascular health.

## Contribution

This study shows that serum ALA concentration, not dietary intake, is associated with reduced arterial stiffness, highlighting individual variation in ALA metabolism.

## Key findings

- Serum ALA concentration was negatively associated with brachial-ankle pulse wave velocity (baPWV), indicating reduced arterial stiffness.
- No significant correlation was found between ALA intake and serum n-3 fatty acid concentrations.
- Serum arachidonic acid was positively associated with baPWV.

## Abstract

Our previous study showed that α-linolenic acid (ALA) intake was associated with a reduction in brachial-ankle pulse wave velocity (baPWV) in healthy middle-aged Japanese women. However, it remains unclear whether this effect depends on the ingested ALA itself or its metabolites. This study aimed to clarify two points: first, whether there is a relationship between ALA intake and serum n-3 fatty acid concentrations; and second, whether ALA intake or serum concentrations of n-3/n-6 fatty acids are related to the previously reported effect of ALA on maintaining vascular flexibility.

We conducted a post hoc analysis of a previously reported randomized controlled trial. Correlation analyses assessed the relationships between ALA intake and serum n-3 fatty acids. Associations of baPWV with n-3/n-6 fatty acid intake and serum concentrations were tested using an analysis of covariance-type linear model.

No significant correlation was found between ALA intake and serum n-3 fatty acid concentrations. Serum ALA correlated positively with serum docosapentaenoic acid (DPA) (p < 0.001, r = 0.444), docosahexaenoic acid (DHA) (p = 0.006, r = 0.292), and the sum of serum eicosapentaenoic acid, DPA, and DHA (p = 0.009, r = 0.275). ALA intake was not associated with baPWV, whereas serum ALA showed a significant negative association with baPWV (p = 0.027, regression coefficient: −2.45); serum arachidonic acid showed a significant positive association (p = 0.047, regression coefficient: 1.11). No associations were observed for other n-3/n-6 fatty acids.

This study suggests substantial inter-individual variation in the relationship between ALA intake and serum ALA concentration. Furthermore, it suggests that serum ALA concentration, rather than ALA intake, may be more closely associated with vascular stiffness, as assessed by baPWV.

https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000060078, identifier UMIN000052677.