Phenolic-rich EVOO and prebiotics in sarcopenia in older adults: FOOP-Sarc pilot RCT
EVOO combined with prebiotic favorably increased rectus femoris cross-sectional area and thickness vs. EVOO alone at end-of-intervention in older adults with probable sarcopenia, but the trial enrolled only 38 participants.
Context
Sarcopenia affects approximately 11% of Europeans over 60 and is projected to rise to 22% by 2045, with consequences including falls, loss of independence, and increased mortality. Low-risk, home-applicable nutritional strategies are needed. EVOO polyphenols and prebiotics have plausible mechanisms via anti-inflammatory and gut microbiota pathways, but clinical evidence remains scarce.
What the study showed
At end-of-intervention, EVOO+PREB vs. EVOO increased rectus femoris CSA in all participants (mean difference: +0.827 cm², 95% CI [0.16; 1.5], p=0.017) and in females (+0.569 cm², 95% CI [−1.0; −0.08], p=0.024), and rectus femoris thickness in all participants (+0.195 cm, 95% CI [0.04; 0.35], p=0.015) and females (+0.179 cm, 95% CI [0.05; 0.31], p=0.009). At 12-week follow-up, both EVOO and EVOO+PREB increased skeletal muscle mass and appendicular skeletal muscle mass vs. ROO by BIA; absolute baseline-to-follow-up values were not reported. EVOO alone vs. ROO increased muscle mass indices and improved overall quality of life in females at follow-up. No significant differences in muscle strength or physical performance were reported.
How it was done
12-week randomized, double-blind, parallel, placebo-controlled, three-arm clinical trial plus 12-week post-intervention follow-up. Participants (n=38) allocated to ROO (n=13), EVOO (n=14), or EVOO+PREB (n=11). All groups received co-created dietary and physical activity recommendations. Muscle outcomes assessed by ultrasound and BIA.
Effect magnitude
Largest reported effect: rectus femoris CSA (EVOO+PREB vs. EVOO): +0.827 cm² (95% CI [0.16; 1.5]); clinical relevance is uncertain given extremely small per-arm samples (n=11–14).
Limitations
Very small sample (n=38, 11–14 per arm) with 82% female participants, limiting generalizability and subgroup power. Formal risk-of-bias assessment tool (e.g., RoB 2) not reported. Absence of absolute pre/post BIA values prevents calculation of real effect size on muscle mass. The 12-week post-intervention follow-up cannot distinguish true persistence from BIA hydration variation. Concurrent behavioral intervention (diet+exercise) in all arms prevents isolation of EVOO or prebiotic effects.
In clinical practice
Clinicians should not modify sarcopenia management protocols based on this single pilot-sized trial. Evidence is insufficient to recommend phenolic EVOO or prebiotic as standalone treatments. The study supports only the hypothesis that the combination warrants testing in adequately powered trials.
What is still missing
RCTs with ≥150 participants per arm, sex-balanced samples, muscle strength and physical performance as primary outcomes, and muscle mass validated by DEXA or MRI to confirm and quantify observed effects.