Mitochondrial function declines with aging, driving many age-related conditions, including Alzheimer’s disease. A recent study in mice found that urolithin A, a compound derived from pomegranates and walnuts, promotes mitophagy – the targeted destruction of damaged mitochondria – in the brain.

Researchers fed older mice urolithin A (200 milligrams per kilogram of body weight) daily for five months. They subjected the animals to various learning and memory tests, assessed their sense of smell, and examined their brains.

They found that urolithin A markedly improved the animals' learning, memory, and sense of smell, enhanced memory-related brain functions, and reduced the accumulation of amyloid-beta and tau protein (hallmarks of Alzheimer’s disease). Urolithin A also improved the function of lysosomes, cellular structures that play a crucial role in mitophagy, by breaking down and recycling damaged mitochondria.

These findings suggest that urolithin A boosts mitophagy in mice, improving brain health and cognitive function. Urolithin A is a byproduct of gut microbial metabolism of ellagic acid, a bioactive compound found in pomegranates and walnuts. The capacity to form urolithin A from ellagic acid varies considerably from person to person (depending on gut microbial composition) and decreases with age.

Due to the low quantities of ellagic acid in foods and the poor conversion rate, achieving a human dose comparable to that used in this study likely would require supplemental intake. Nevertheless, the findings align with other evidence suggesting that long-term dietary intake of foods containing ellagic acid benefits cognitive health.