A US research team found that urolithin A, a byproduct of a person's gut bacteria, appears to promote muscle endurance and mitochondrial health in humans, when taken as an oral supplement.
Urolithin A is a byproduct and a diet comprising polyphenols found in pomegranates, berries and nuts. Because diet, age, genetics and disease affect the makeup of the gut microbiome, people produce urolithin A at variable rates. Therefore, the compound is also produced and sold as a dietary supplement.
A new study carried out at the University of Washington and published in the latest issue of the journal JAMA Network Open, the researchers proved that supplemental urolithin A has been shown in animal tests and molecular studies of humans to stimulate mitophagy, a process explained as "mitochondrial quality control."
Mitochondria are like batteries that power the cells in your body. But over time they break down. The process of mitophagy recognizes this failure and proactively tears down the mitochondria, reducing it to elemental components that a cell can reuse. But with aging, mitophagy becomes less efficient and your body accumulates this pool of failing mitochondria. It's one way that muscles become less functional as we age.
The researchers studied a small cohort of people over age 65 who were randomized to receive a placebo or a daily supplement of 1,000 mg urolithin A for four months. Each of the 66 subjects was confirmed at the outset to have average or subpar capacity to produce adenosine triphosphate (ATP), which mitochondria produce to help cells perform myriad functions.
“The results showed that muscle endurance was improved in the supplemented group compared to the placebo group. Endurance was measured with exercises involving the hand and leg,” lead author David Marcinek explained in a report posted on the university’s website.
Researchers measured the increase in the number of muscle contractions until fatigue and found just taking a supplement actually improved muscle endurance, which means it could contribute to strengthen muscles in the absence of exercise.