# Omega‐3 fatty acid supplementation does not attenuate declines in skeletal muscle mitochondrial area in young, healthy females during immobilization

## TL;DR

This study found that omega-3 fatty acid supplementation does not prevent the loss of mitochondrial area in skeletal muscle of young, healthy females during leg immobilization.

## Contribution

The study reveals that omega-3 supplementation does not prevent immobilization-induced mitochondrial loss in specific muscle regions.

## Key findings

- Subsarcolemmal mitochondrial content decreased significantly during immobilization and remained low after recovery.
- Omega-3 supplementation did not prevent the decline in subsarcolemmal mitochondrial content.
- Intermyofibrillar mitochondrial content was lower than baseline after recovery, but not during immobilization.

## Abstract

Mitochondrial subcellular area influences function. Muscle disuse reduces mitochondrial content; however, its effect on mitochondrial subcellular location is unclear. Omega‐3 fatty acid (n‐3) attenuates declines in muscle mass and mitochondrial function during disuse; however, whether n‐3 supplementation prevents the decline in mitochondrial content has not been examined. We investigated the effects of 2 weeks of leg immobilization followed by 2 weeks of remobilization on skeletal muscle mitochondrial content and subcellular localization with and without n‐3 supplementation. Twenty healthy females supplemented with n‐3 (2.97 g EPA and 2.03 g DHA) or control (isoenergetic sunflower oil) during 2 weeks of unilateral leg immobilization and 2 weeks of remobilization. Vastus lateralis biopsies were taken for electron microscopic analysis of mitochondrial content. Subsarcolemmal (SS) mitochondrial content decreased during immobilization (control: −9%, n‐3: −66%, p = 0.009) and remained lower following recovery (control: −41%, n‐3: −42%, p = 0.005). This effect was driven by the n‐3 group (p < 0.02). Intermyofibrillar (IMF) mitochondrial content did not decline during immobilization, but was lower than baseline following recovery in the central (p = 0.01) IMF. The effects of leg immobilization on mitochondrial content differ by location, are not reversed with short‐term recovery, and are influenced by n‐3 supplementation.