Shatavari Supplementation in Postmenopausal Women Improves Handgrip Strength and Increases Vastus Lateralis Myosin Regulatory Light Chain Phosphorylation But Does Not Alter Markers of Bone Turnover: A Randomised Controlled Trial

Abstract

Background: Shatavari has long been used as an Ayurvedic herb for women's health, but empirical evidence for its effectiveness has been lacking. Shatavari contains phytoestrogenic compounds that bind to the estradiol receptor, and may therefore benefit postmenopausal women since postmenopausal estradiol deficiency contributes to sarcopenia and osteoporosis. Methods: In a randomised double-blind trial, 20 postmenopausal women (68.5 ± 6 y) ingested either placebo (N=10) or shatavari (N=10; 1000 mg/d, equivalent to 26,500 mg/d fresh weight shatavari) for 6 weeks. Handgrip and knee extensor strength were measured at baseline and at 6 weeks. Vastus lateralis (VL) biopsy samples were obtained. Data are presented and analysed (t test/Mann Whitney U) as difference scores (Week 6 – baseline, median ± interquartile range). Results: Handgrip, (but not knee extensor) strength was improved by shatavari supplementation (shatavari +0.7 ± 1.1 kg, placebo -0.4 ± 1.3 kg; p=0.04). Myosin regulatory light chain phosphorylation, a known marker of improved myosin contractile function, was increased in VL following shatavari supplementation (immunoblotting; placebo -0.08 ± 0.5 a.u. shatavari +0.3 ± 1 arbitrary units (a.u.); p=0.03). Shatavari increased phosphorylation of Aktser473 (Aktser473 (placebo -0.6 ± 0.6 a.u. shatavari +0.2 ± 1.3 a.u; p=0.03) in VL. Shatavari supplementation did not alter plasma markers of bone turnover (P1NP, β-CTX) and stimulation of human osteoblasts with pooled sera (N=8 per condition) from placebo and shatavari supplementation conditions did not alter cytokine or metabolic markers of osteoblast activity. Conclusions: Shatavari may improve muscle function and contractility via myosin conformational change and warrants further investigation of its utility in conserving musculoskeletal function in postmenopausal women. Trial Registration: Retrospectively registered at clinicaltrials.gov as NCT05025917 on 30/08/21.