OKLAHOMA CITY – A dietary supplement called urolithin A increased blood flow to the brain during mental activity in middle-aged adults with obesity, according to a University of Oklahoma study published in JAMA Network Open. The findings could help researchers better understand the relationship between the supplement, blood vessel function and brain health.
Obesity is associated with changes in blood vessel function that can affect circulation throughout the body, including the brain. Researchers wanted to determine whether urolithin A could improve blood vessel function in adults with obesity. To find out, they conducted a randomized clinical trial involving 50 adults aged 40 to 64. Participants received either 1,000 milligrams of urolithin A daily or a placebo for four weeks.
Researchers found that participants who took urolithin A experienced a greater increase in blood flow to the brain while performing a challenging memory task than those who received the placebo. The change was particularly apparent in the left dorsolateral prefrontal cortex, a region of the brain involved in working memory. However, the supplement did not significantly improve the function of blood vessels in the arm, and participants did not perform significantly better on memory tests. This is the first human study to report an effect of urolithin A on cerebrovascular function, the researchers said.
"The brain needs an adequate supply of blood to meet the demands of mental activity," said the study's first author, Ana Clara da Costa Pinaffi Langley, Ph.D., an assistant professor in the Department of Nutritional Sciences at the OU College of Allied Health on the OU Harold Hamm Health Campus. "We found that urolithin A increased blood flow to the brain during a memory task, suggesting the supplement may help the brain meet its increased need for oxygen and nutrients when it is working harder. We plan to conduct more research to understand what this finding means for brain health."
Urolithin A is a substance produced when certain gut bacteria break down compounds found in foods such as strawberries, pomegranates and walnuts. The amount that people naturally produce varies, but existing research suggests that a person's ability to produce urolithin A decreases with age and as body mass index goes up, Langley said. Urolithin A is also available as a dietary supplement.
The supplement was well-tolerated during the study. However, the researchers noted that the trial was relatively small and conducted at a single site, and that longer studies involving more participants are needed to understand the effects of urolithin A.
"These findings offer an interesting starting point for understanding how urolithin A affects the brain," said study co-author Andriy Yabluchanskiy, M.D., Ph.D., an associate professor in the Department of Neurosurgery at the OU College of Medicine. "Although we saw increased blood flow to the brain during mental activity, participants did not demonstrate measurable improvements in memory or attention. Future studies will need to determine whether taking the supplement for a longer period leads to meaningful improvements in cognitive function or other health benefits."
Langley added that the ultimate goal of the research is to extend healthspan. "The idea is to mitigate cognitive decline," she said. "We want to expand the time that people are living healthier lives."
