Resting metabolic rate and skeletal muscle SERCA and Na + /K + ATPase activities are not affected by fish oil supplementation in healthy older adults.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 32342642 · doi:10.14814/phy2.14408
What was done
Healthy older adults (n = 24: 16 females, 8 males; mean age 65 ± 1 years) were randomly assigned to receive either olive oil (5 g/day) or fish oil (5 g/day providing 2 g/day EPA and 1 g/day DHA) for 12 weeks. Resting metabolic rate (RMR) and substrate oxidation were measured following an overnight fast at baseline and week 12. Skeletal muscle biopsies were obtained at weeks 0 and 12 to assess kinetic parameters, maximal activity, and protein content of sarcoplasmic reticulum Ca2+ ATPase (SERCA) and Na+/K+ ATPase (NKA).
What was found
Both supplementation groups showed a main effect of time, with a 5% decrease in RMR and an 18% decrease in fat oxidation over 12 weeks, with no significant difference between the fish oil and olive oil groups. Supplementation with fish oil or olive oil had no effect on the kinetic parameters of SERCA and NKA maximal activity, nor on SR or NKA protein expression. Specific variance metrics and p-values were not reported in the abstract.
Why it matters
These findings suggest that omega-3 supplementation does not stimulate energy expenditure or alter skeletal muscle SERCA and NKA ion pump activity in healthy older adults, challenging the proposed calcium leak-pump mechanism as a driver of elevated resting metabolism.
Limits
The study had a small sample size (n = 24 total, split across two groups), limiting statistical power. The study examined only healthy older adults, precluding direct generalization to younger or metabolically impaired populations. The abstract omits detailed numerical data, confidence intervals, and p-values for pump kinetics and protein expression.
Cited by
- contradicts Studies have shown that DHA and EPA increase resting metabolic rate by 19% and exercise fat oxidation by 27% in older women.