Older adults (aged ≥60 years) are the fastest-growing age group in the world and are projected to represent 1 in every 4 adults by 2050. Aging is associated with a progressive loss of muscle mass and strength that manifests as reduced physical activity performance and endurance capacity, imposing a burden on both the individual and society.
Studies have shown that mitochondrial dysfunction plays an important role in age-related diseases. In skeletal muscle, the decline in mitochondrial efficiency and capacity for adenosine triphosphate (ATP) production is associated with decreased performance and fatigue.
Urolithin A is a natural food metabolite of the gut microbiome that has been shown to stimulate mitophagy and improve muscle function in aged animals, and in models of muscular dystrophy, while also being safe, and able to induce mitochondrial gene expression in older adults.
It is the end product created when bacteria in the gut break down ellagitannins, which are polyphenols found in fruits such as pomegranates, strawberries, walnuts, and raspberries. The substance does not appear naturally in its end form, so we normally rely on the beneficial bacteria in the microbiome, our internal ecology of gut bacteria, to convert the polyphenols into urolithin A.
New Study Results
In a recently published study in the journal JAMA Network, researchers evaluated the long-term supplementation with urolithin A and its effects in improving mitochondrial function and muscle performance in older adults.
The study included 66 individuals that were randomized either to take urolithin A (n=33) or the placebo (n=33) intervention group. The median age of the participants was 71.7 years.
According to their study urolithin A significantly improved muscle endurance, with an increase in the number of muscle contractions until fatigue from baseline. Also, the plasma levels of several acylcarnitines, ceramides, and C-reactive proteins were decreased compared with placebo. The mean increase from baseline in the 6-minute walk distance was 60.8 meters in the urolithin A group and 42.5 meters in the placebo group.
The researchers concluded that the supplement urolithin A was safe and well-tolerated, and was beneficial for muscle endurance and plasma biomarkers, suggesting that it may counteract age-associated muscle decline.
Sophia Liu, Davide D’Amico, Eric Shankland, Saakshi Bhayana, Jose M. Garcia, Patrick Aebischer, Chris Rinsch, Anurag Singh, David J. Marcinek. Effect of Urolithin A Supplementation on Muscle Endurance and Mitochondrial Health in Older Adults. JAMA Network Open, 2022; 5 (1): e2144279 DOI: 10.1001/jamanetworkopen.2021.44279