Do the effects of krill oil supplementation on skeletal muscle function and size in older adults differ by sex, age or BMI: A secondary analysis of a randomised controlled trial.

Increases in muscle strength, size, and physical function in response to krill oil supplementation were comparable across age, sex and BMI subgroups.

• All subgroup comparisons yielded P > 0.05 for muscle size, strength, and physical function outcomes.
• Subgroups were defined by sex (male/female), age (≤70 years/>70 years), and BMI (≤24.9 kg/m²/>25 kg/m²).
• Participants received either 4 g/day krill oil or a control oil for 6 months.
• 94 participants were included: Control n = 45 (27 women, 18 men); Krill n = 49 (26 women, 23 men).

The Mwave response to krill oil supplementation differed by sex, with increases observed in males in the krill group but no change in females.

• Males in the krill group showed an increase in Mwave of +3.80 [1.72–5.88] mV (p = 0.016).
• Males in the control group showed a tendency for a decrease in Mwave of -3.71 [1.58–6.05] mV (p = 0.059).
• No change over time in Mwave was observed in females in either the krill or control groups.
• The Mwave reflects skeletal muscle membrane excitability as a neuromuscular outcome measure.

The study was a secondary exploratory analysis of a randomised, double-blind, controlled trial of krill oil supplementation in healthy older adults.

• The parent trial was registered as NCT04048096 and conducted between March 2018 and March 2020.
• Eligible participants were men and women aged ≥65 years, with BMI < 35 kg/m², engaging in <1 hour per week of structured exercise.
• The intervention consisted of 4 g/day krill oil or a control oil administered over 6 months.
• Outcomes measured included muscle size, strength, and neuromuscular function before and after the intervention period.