The Effect of Shatavari Supplementation on Skeletal Muscle Strength and Neuromuscular Function in Post-Menopausal Women.

Abstract

Shatavari is an ayurvedic herb that has traditionally been used to support ‘female health’. There is a lack of empirical evidence to support its effectiveness. Shatavari contains phytoestrogenic compounds capable of binding to oestradiol receptors. Post-menopausal women experience a deficiency in oestradiol that can contribute to a decline in muscle health and strength, and ultimately sarcopenia. Some studies have suggested an ergogenic benefit of Shatavari in skeletal muscle. This area remains underexplored. In a randomised, double-blind placebo-controlled trial, 22 post-menopausal women (mean ± SD; age: 62.72 ± 5.32 years; height: 1.66 ± 0.07 m; weight: 68.25 ± 11.95 kg), were supplemented with either placebo (N = 11) or Shatavari (N = 11; 1000 mg/day) for 8 weeks in conjunction with a lower-limb resistance training (RT) programme consisting of knee extension (KE) and leg press (LP) exercises. 1RM (KE and LP), hand grip strength (HGS), and isometric knee extension (IKE) were measured at baseline and post-intervention. Vastus Lateralis (VL) biopsies were obtained before and after the training programme. Neuromuscular function (NMF) outcomes were measured pre- and post-intervention. Data are presented as % differences from pre- to post-measures. Analysis of covariance (ANCOVA) were used to analyse the data, with baseline measures used as covariates. The results demonstrated a main effect of the supplement on the number of repetitions completed in each set and the training load achieved in each week for LP but not KE (repetitions completed: LP, p = 0.049; KE, p = 0.286; training load: LP, p = 0.01, SH 17.21% vs PL 3.24% increase; KE, p = 0.214, SH 4.72% vs PL -4.09% increase). There was a significant main effect of the supplement on weight lifted per rep for both KE and LP (KE, p = 0.043, SH 50.98% vs PL 25.56% increase; LP, p = 0.03, SH 77.41% vs PL 54.67% increase). However, there was no main effect of Shatavari on training-induced strength improvements following 8 weeks of supplementation. Shatavari supplementation significantly reduced potentiated half relaxation time (p = 0.021). Proteins in pathways associated with striated muscle contraction were significantly downregulated. Notably, proteins in pathways related to MAPK/ERK signalling were significantly upregulated alongside pathways related to Ca2+ production and oestrogen signalling. Proteins related to vesicle-mediated transport and immune function were also upregulated. Shatavari supplementation, in conjunction with RT, may improve muscle function and contractility. Further research is warranted to investigate its ability to enhance musculoskeletal function in larger and frailer cohorts. Keywords: asparagus racemosus, skeletal muscle, resistance training, nutrition