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.
Level 2 - randomized trial
Secondary subgroup analysis of an individual randomized controlled trial
PubMed 41344001 · doi:10.1016/j.jnha.2025.100747
What was done
This secondary exploratory analysis of a double-blind, randomized controlled trial (NCT04048096) evaluated whether the effects of 6 months of krill oil supplementation (4 g/day) versus control oil differed by age (≤70 vs >70 years), sex (men vs women), or BMI (≤24.9 vs >25 kg/m²). Participants were 94 older adults (≥65 years, BMI < 35 kg/m², <1 h/week structured exercise; 49 krill oil, 45 control). Outcomes measured before and after intervention included muscle size, strength, physical function, and neuromuscular function.
What was found
Improvements in muscle strength, size, and physical function following krill oil supplementation were comparable across sex, age, and BMI subgroups (all P > 0.05 for subgroup interactions). Neuromuscular responses showed a sex-specific difference in M-wave amplitude: females showed no significant change in either group, whereas males receiving krill oil had a significant increase (+3.80 mV, 95% CI [1.72, 5.88], p = 0.016) compared to a trend toward a decrease in control males (-3.71 mV, 95% CI [1.58, 6.05], p = 0.059).
Why it matters
The findings suggest that the skeletal muscle benefits of krill oil in older adults are broadly applicable across both sexes, older age brackets, and normal-to-overweight BMI categories.
Limits
As an exploratory secondary analysis with n = 94, subgroup sample sizes were small (e.g., 18–27 per sex/arm), reducing statistical power to detect modest interaction effects. The abstract does not specify the control oil composition or baseline dietary intake.
Cited by
- supports Research by Bettina Mittendorfer's group showed that omega-3 fatty acid supplementation increases muscle size in older adults.