The study, which involved 66 adults aged 65 to 90 years, found that, in comparison to those using placebo, people who took 1000 milligrams (mg) of urolithin A experienced an improvement in muscle endurance for leg and hand skeletal muscles.
In addition, following urolithin A supplementation, plasma levels of many acylcarnitines, ceramides (biomarkers of mitochondrial health), and C-reactive protein were reduced.
The process
Participants were recruited through social media platforms and advertisements, as well as from previous study referrals.
To be eligible, as well as meeting the age requirements, people had to be ambulatory, healthy, able to conduct daily living activities without assistance, read and speak English fluently, and sign a consent form.
The double-blind trial was carried out in Seattle, Washington, at a medical centre and cancer research centre. [WC1]
Volunteers were randomised to receive daily oral supplementation of either 1000 mg urolithin A or placebo for a total of four months.
Assessments including plasma analysis of biomarkers and muscle fatigue tests took place at baseline, two months and four months.
A walking distance over a six-minute period and maximal ATP production were tested using magnetic resonance spectroscopy at baseline, four months and the end of the study.
Conclusions
Urolithin A supplementation was found to be safe and well tolerated among those assessed.
The improvements in the six-minute walk distance and highest ATP production in the hand muscle were not considerable in the urolithin A group compared to the placebo group. However, long-term consumption of urolithin A supplements did aid muscle endurance and plasma biomarkers. This indicated that it may counteract age-related muscle decline.