A 12-Week Randomized Double-Blind Placebo-Controlled Clinical Trial, Evaluating the Effect of Supplementation with a Spinach Extract on Skeletal Muscle Fitness in Adults Older Than 50 Years of Age

Study answer

What this study found

Spinach extract supplementation plus a 12-week resistance training program produced greater improvements in knee isokinetic and isometric strength and in muscle quality than placebo. Lean/muscle mass increased and fat mass decreased in both groups, with larger magnitudes in the spinach group. Quality of life in role physical and role emotional domains improved with the spinach extract. Adherence was high and no adverse events were reported. No dietary intake changes were observed. Conclusion: spinach extract may enhance exercise-induced muscle adaptations and support healthy aging when…

Study & population

Design: single-center, randomized, double-blind, placebo-controlled trial with two parallel arms.

Intervention

Spinach extract (Spinacia oleracea L.), four capsules per day (500 mg each, total 2 g/day) taken in two divided doses (breakfast and lunch) for 12 weeks.

Key limitation

Small sample size; single-center; predominantly female sample (8 men, 37 women); exploratory gender analyses with limited male representation; dietary intake not tightly controlled; 12-week duration; findings may not generalize to broader populations; potential confounding from the concurrent exercise program.

View full study detailsView sourceOpen PDF

Original abstract