l-Arginine and Beetroot Extract Supplementation in the Prevention of Sarcopenia

Abstract

Aging is associated with a significant decline in neuromuscular function, leading to a reduction in muscle mass and strength. The aim of the present report was to evaluate the effect of supplementation with nitric oxide precursors (l-arginine and beetroot extract) in muscular function during a training period of 6 weeks in elderly men and women. The study (double-blind, placebo-controlled) involved 66 subjects randomly divided into three groups: placebo, arginine-supplemented and beetroot extract-supplemented. At the end of this period, no changes in anthropometric parameters were observed. Regarding other circulating parameters, urea levels were significantly (p < 0.05) lower in women of the beetroot-supplemented group (31.6 ± 5.9 mg/dL) compared to placebo (41.3 ± 8.5 mg/dL) after 6 weeks of training. In addition, the circulating creatine kinase activity, as an index of muscle functionality, was significantly (p < 0.05) higher in women of the arginine- (214.1 ± 162.2 mIU/L) compared to the beetroot-supplemented group (84.4 ± 36.8 mIU/L) at the end of intervention. No significant effects were noticed with l-arginine or beetroot extract supplementation regarding strength, endurance and SPPB index. Only beetroot extract supplementation improved physical fitness significantly (p < 0.05) in the sprint exercise in men after 6 weeks (2.33 ± 0.59 s) compared to the baseline (2.72 ± 0.41 s). In conclusion, beetroot seems to be more efficient during short-term training while supplementing, preserving muscle functionality in women (decreased levels of circulating creatine kinase) and with modest effects in men.

Combined L-Citrulline Supplementation and Slow Velocity Low-Intensity Resistance Training Improves Leg Endothelial Function, Lean Mass, and Strength in Hypertensive Postmenopausal Women

“…The present study showed significant increases in leg LM after 8 weeks of CIT supplementation with the addition of SVLIRT during the last 4 weeks compared to PL. In older obese rats, 12 weeks of ARG supplementation alone enhanced soleus muscle mass via NO production and protein synthesis [ 54 ], but no effect was found in older adults [ 55 ]. On the other hand, findings in malnourished rats and older adults supplemented with CIT alone showed improvements in muscle protein synthesis [ 56 ] and total LM [ 21 ].…”

“…The discrepancy between the previous and our findings may be attributed to lower CIT dose and duration of the combined intervention. In addition, ARG (3 g/day) supplementation during a combined aerobic and strength training for 6 weeks did not increase LM in older adults [ 55 ]. Low ARG dose and high ARG catabolism by intestinal arginase may have resulted in reduced circulating ARG availability for effectiveness in skeletal muscles.…”

The effects of beetroot and nitrate supplementation on body composition: a GRADE-assessed systematic review and meta-analysis

“…A total of twelve RCTs involving 500 participants (301 cases and 299 controls) were included in this meta-analysis (14,(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31) . Six of the studies had two trial arms (14,25,26,28,29,31) .…”

“…A total of twelve RCTs involving 500 participants (301 cases and 299 controls) were included in this meta-analysis (14,(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31) . Six of the studies had two trial arms (14,25,26,28,29,31) . Table 1 provides the characteristics of the twelve included trials.…”

“…The studies were published between 2016 and 2022. Three were cross-over trials (14,25,31) and nine studies used a parallel design (21)(22)(23)(24)(26)(27)(28)(29)(30) . The duration of interventions ranged from 4 to 12 weeks and sample sizes in the trials were between 10 and 80 participants.…”