As we age, we experience a decline in muscle function and reduced exercise capacity, which can lead to loss of independence and increased risk of falls. Mitochondrial dysfunction is a key contributor to age-related muscle decline, and it has been suggested that improving mitochondrial health may help counteract this decline.
Urolithin A is a natural gut microbiome–derived food metabolite that has been shown to improve muscle function in older animals and induce mitochondrial gene expression in older humans. A randomized clinical trial investigated the effect of urolithin A supplementation on skeletal muscle performance and mitochondrial health in older adults.
Clinical trial
The study was conducted at a medical center and a cancer research center in Seattle, Washington, and included 66 adults aged 65 to 90 years. Participants were randomized to receive daily oral supplementation with either 1,000 mg urolithin A or a placebo for 4 months. Muscle fatigue tests and plasma analysis of biomarkers were assessed at baseline, 2 months, and 4 months.
The primary endpoint was a change from baseline in the 6-minute walk distance and a change from baseline to 4 months in maximal ATP production in the hand skeletal muscle. The secondary endpoints were changes in muscle endurance of 2 skeletal muscles (tibialis anterior [TA] in the leg and first dorsal interosseus [FDI] in the hand). Adverse events were recorded and compared between the 2 groups during the intervention period.
Findings
The study found that urolithin A supplementation was safe and well-tolerated in the assessed population. Compared with placebo, urolithin A significantly improved muscle endurance (i.e., the number of muscle contractions until fatigue) in both the FDI and TA at 2 months. Plasma levels of several acylcarnitines, ceramides, and C-reactive protein were decreased by urolithin A, compared with placebo, at 4 months. However, the improvements in the 6-minute walk distance and maximal ATP production in the hand muscle were not significant in the urolithin A group compared with the placebo group.
Implications
These findings suggest that urolithin A may be a promising approach to counteracting age-associated muscle decline. The improvements in muscle endurance and plasma biomarkers indicate that urolithin A was beneficial for skeletal muscle performance and mitochondrial health in older adults. However, further research is needed to confirm these findings and determine the optimal dosage and duration of urolithin A supplementation.
Conclusion
Urolithin A is a natural gut microbiome–derived food metabolite that has shown promise in improving muscle endurance and mitochondrial health in older adults. This randomized clinical trial found that urolithin A supplementation was safe and well-tolerated in the assessed population and may be a promising approach to counteracting age-associated muscle decline. Future research is needed to confirm these findings and determine the optimal dosage and duration of urolithin A supplementation.
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