Highlight
This recent study reveals that short-term dietary nitrate supplementation through beetroot juice significantly enhances muscle contractile properties, submaximal force production, and fatigue resistance in older adults, whereas no equivalent improvements were observed in young adults.
The benefits correspond with increased plasma nitrate and nitrite levels, emphasizing nitrate’s potential role in ameliorating age-associated muscle contractile decline.
Study Background and Disease Burden
Age-related decline in skeletal muscle function, also termed sarcopenia, is a major contributor to reduced mobility, increased fall risk, and consequent morbidity in the elderly population. Impaired muscle contractility and increased fatigability significantly impact quality of life and independence among older adults. At the cellular level, disturbed calcium (Ca2+) handling within skeletal muscle fibers is a key mechanism underlying diminished muscle function with aging.
Dietary nitrate (NO3-), a naturally occurring compound in vegetables such as beetroot, is metabolized to nitrite (NO2-) and subsequently to nitric oxide (NO), a molecule capable of modulating muscle contractile properties and mitochondrial efficiency. Previous studies have demonstrated that nitrate supplementation can improve muscle performance and reduce fatigue in younger populations. However, given the age-related disruption in Ca2+ dynamics, the potential for nitrate supplementation to restore muscle contractile function in older adults remains underexplored.
Study Design
This randomized, double-blind, placebo-controlled crossover study involved 22 healthy adults divided into two groups: 11 older adults (mean age 69 ± 4 years) and 11 young adults (mean age 26 ± 2 years). Participants ingested either nitrate-rich beetroot juice (BR) providing dietary nitrate or a nitrate-depleted placebo (PLA) daily for 7 days.
Outcomes were assessed in the dominant and nondominant leg plantar flexors with multiple measurements: maximal voluntary isometric contraction (MVIC), electrically evoked potentiated single twitches and double twitches at 100 Hz (Db100) on the tibial posterior nerve, a fatigue test at 70% MVIC until exhaustion, and the force-frequency relationship via various electrical stimulation frequencies.
Key Findings
Beetroot juice supplementation effectively elevated plasma nitrate and nitrite concentrations by more than sevenfold in both age groups compared to placebo, confirming biochemical uptake.
Despite this, neither maximal voluntary contraction (MVC) nor twitch forces (Tw pot and Db100) changed significantly after BR supplementation in either young or older adults, suggesting no effect on maximal contractile force.
Notably, in older adults only, BR supplementation significantly decreased the area under the curve for Db100 double twitch responses (mean change -7 ± 6 N·s versus PLA) and shortened half relaxation time (-0.05 ± 0.06 seconds), indicating enhanced contractile efficiency and quicker muscle relaxation.
Furthermore, time to exhaustion during the fatigue test was prolonged by 32 ± 43 seconds in the older cohort (p<0.02), and submaximal force produced by electrical stimulation pulses increased markedly (p<0.001). These results collectively suggest improved endurance and submaximal muscle force generation post nitrate supplementation in the elderly.
No significant fatigue resistance or force enhancements were observed in young adults, underscoring an age-specific effect of dietary nitrate.
Expert Commentary
These findings support the hypothesis that dietary nitrate supplementation mitigates some age-related deteriorations in muscle contractile function possibly by modulating Ca2+ handling or sensitivity within muscle fibers. The lack of effect on maximal voluntary contraction suggests that nitrate’s benefits may be more prominent during submaximal muscle activities and fatigue resistance rather than peak force output.
The age-dependent benefit aligns with the concept that impaired nitric oxide bioavailability and altered calcium handling contribute significantly to sarcopenic muscle dysfunction. By enhancing nitric oxide signaling, nitrate supplementation may restore calcium kinetics, leading to improved muscle relaxation and endurance.
This study’s randomized, placebo-controlled design strengthens the validity of results, though the relatively small sample size and short supplementation duration indicate a need for larger and longer-term clinical trials. Furthermore, the precise molecular mechanisms warrant further investigation to fully elucidate nitrate’s role in muscle calcium dynamics.
Conclusion
Short-term dietary nitrate supplementation with beetroot juice offers a promising, non-pharmacologic intervention to improve muscle contractile properties, submaximal force production, and fatigue resistance in older adults. These effects were not observed in younger individuals, highlighting a potential therapeutic window targeting age-associated muscle decline.
Given the public health burden of sarcopenia, incorporating nitrate-rich dietary elements or supplements may improve functional outcomes and quality of life for the aging population. Future research should focus on confirming these effects in larger cohorts, exploring underlying mechanisms, and establishing optimized dosing regimens.
References
Rasica L, Colosio M, Ferri A, Baldassarre G, Easton C, Burleigh M, Vernillo G, Bottinelli R, Marzorati M, Porcelli S. BEETter AGING: Short-Term Dietary Nitrate Supplementation Enhances Muscle Contractile Properties in Older But Not in Young Adults. Med Sci Sports Exerc. 2025 Aug 1;57(8):1721-1731. doi: 10.1249/MSS.0000000000003708. Epub 2025 Mar 18. PMID: 40098056.
Jones AM. Dietary nitrate supplementation and exercise performance. Sports Med. 2014;44 Suppl 1(Suppl 1):S35-45. doi:10.1007/s40279-014-0144-z.
Coggan AR, Peterson LR, Halliwill JR, et al. Impact of dietary nitrate on the contractile properties of human skeletal muscle. Nitric Oxide. 2015;48:16-21. doi:10.1016/j.niox.2015.02.007.
Frontera WR, Ochala J. Skeletal muscle: a brief review of structure and function. Calcif Tissue Int. 2015;96(3):183-95. doi:10.1007/s00223-014-9915-y.
