MNT also spoke with Alyssa Simpson, RDN, CGN, CLT, a registered dietitian, certified gastrointestinal nutritionist, and owner of Nutrition Resolution in Phoenix, Arizona, who was not involved in the study.

She noted the study’s strengths and weaknesses:

“While the study provides important insights into urolithin A’s potential benefits for Alzheimer’s, it is limited by its reliance on animal models and its narrow focus on specific pathways, possibly overlooking broader systemic interactions. However, its strengths lie in the thorough assessment of multiple pathological mechanisms and investigation of long-term treatment effects, which significantly advances our understanding of urolithin A’s therapeutic role in Alzheimer’s.”

“The research indicates that urolithin A treatment shows potential as a new intervention for Alzheimer’s disease by addressing various pathological mechanisms like neuroinflammation, mitochondrial dysfunction, lysosomal dysfunction, and DNA damage, potentially slowing down the progression of the disease,” Simpson added.

However, “[w]hile research on urolithin A offers promise for Alzheimer’s intervention, additional studies, particularly clinical trials, are required to validate its efficacy and safety in humans,” she cautioned.

Holland agreed but highlighted challenges in determining urolithin A’s outcomes and optimal dosage through randomized controlled trials.

He explained that controlling for diet, gut microbiota, and individual health conditions is difficult, and these factors can influence urolithin A absorption and utilization in the body.

Additionally, Holland said that if subjects consume other polyphenol-rich foods, it complicates isolating the effects of the administered urolithin A from that produced naturally through diet.

More research is needed to determine the best urolithin A doses, and the potential risks of long-term supplement use since both of these are unknown.

“There could be risks associated with trying urolithin A pills for Alzheimer’s intervention since there is limited research on their safety and effectiveness,” cautioned Simpson.

Promoting the body’s urolithin A production through diet may be a more natural and safe approach.

Holland explained that urolithin A is a natural compound produced by gut bacteria when exposed to certain polyphenols, like ellagitannins and ellagic acid, which are present in many fruits and nuts.

Holland and Simpson highlighted some of the best food sources of these polyphenols, including:

• pomegranates
• strawberries
• raspberries
• blackberries
• walnuts

Both experts stated that pomegranate seeds (arils) and peels are especially abundant in polyphenolic compounds that can be converted to urolithin A.

However, Simpson noted that the bioavailability and effectiveness of urolithin A from pomegranate and other foods might vary due to individual differences in gut microbiota, “influencing the extent of potential benefits.”

Holland supported this, remarking that this study’s “findings reiterate the importance of having a diverse and robust gut microbiota to ensure optimal digestion and absorption of nutrients and polyphenols.”

“Although the work was done in mice and cannot be directly generalized to humans, it builds upon previous research and emphasizes that the foods we consume are crucial for brain health,” he concluded.