Circulating Vegetable Omega-3 and Prognosis in Patients With Heart Failure: More Data Are NeededFree Access

Introduction

Recently, Lázaro et al¹ reported that a higher level of serum alpha-linolenic acid (ALA), the main vegetable omega-3, was associated with a better prognosis in patients with heart failure (HF). The study provided important insight for future dietary interventions in HF. However, several points should be considered to provide more evidence in the field.

First, in the study by Lázaro et al,¹ patients with the 3 upper quartiles of ALA were combined to compare vs those with the lowest quartile. However, whether there is a dose-dependent association between ALA and HF prognosis is unclear. It would be interesting if the prognosis in the upper quartiles can be reported respectively (rather than combined) and the P for trend calculated. Furthermore, the restricted cubic spline analysis used to explore the linear/nonlinear associations should be considered.

Second, in the study by Lázaro et al,¹ no significant association between marine omega-3 (including eicosapentaenoic acid and docosahexaenoic acid) and the prognosis of HF was found, which was in contrast with that proposed in the current guideline.² Actually, additional evidence showed that marine omega-3 may have a more robust protective effect in HF than vegetable omega-3.^3,4 The reasons for the inconsistency are unknown. Furthermore, because serum levels of marine omega-3 are significantly associated with ALA,⁵ the mediator effect should be explored or adjusted in the Cox regression model.

Therefore, considering the inconsistent findings with multiple previous studies, as well as the statistical drawback in the study of Lázaro et al,¹ we think that the relationship of ALA to prognosis in HF was still unclear, and more data are needed.

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