Highlights

  • Supplementing with PQQ for 12 weeks slightly improves complex and verbal memory in older adults.
  • PQQ mildly enhances the ability to respond to changes in instructions and to understand and make decisions about rules and concepts, both cognitive parameters, in younger adults.

PQQ is a vitamin-like compound found in soil and various foods like spinach, kiwi, and soybeans. Research examining PQQ has shown that the molecule preserves neurons, and a rat study suggests that it promotes memory formation and retention. Moreover, in healthy, older adults, PQQ reportedly mildly enhances attention, information processing, language memory, and sleep. Despite data pointing to PQQ’s benefits on cognition, the fact that PQQ’s effects have only been measured in older adults begs the question of whether these findings apply across the lifespan.

Published in Food & Function, Ikemoto and colleagues from the Mitsubishi Gas Chemical Company in Japan show that supplementing with 20 mg of oral PQQ per day for 12 weeks mildly enhances complex and verbal memory in older adults. The researchers go on to demonstrate that the same dosing regimen improves cognitive flexibility – the ability to respond to changes in instructions – and executive speed – how quickly one makes decisions about rules and concepts – in younger adults. These findings suggest that PQQ benefits cognition throughout the span of adulthood, albeit in different ways.

PQQ Improves Cognition in Older and Younger Adults

Because PQQ has been shown to improve multiple parameters of cognitive function, Ikemoto and colleagues used a digital test of cognitive function – Cognitrax – to find how PQQ affects these cognitive dimensions. To measure whether PQQ’s cognitive benefits change in different stages of adulthood, the researchers split the study participants into two groups – young and old. The younger age group was between 21 and 40 years old and the old division was between 41 and 65 years old.

The Cognitrax exam analyses revealed that verbal memory and composite memory improved after twelve weeks of supplementation in the old group but not the young group. Verbal memory is a cognitive parameter of language memory, while composite memory combines visual and language memory (complex memory). These results suggest that PQQ improves these aspects of memory in older but not younger adults. These findings didn’t apply at eight weeks of supplementation, implying that PQQ’s benefits increase with time.

(Tamakoshi et al., 2023 | Food & Function) PQQ improves composite and verbal memory in older but not younger adults. Composite (a) and verbal (b) memory significantly improved after 12 weeks (12) for older (Old) adults who took PQQ (red bars) compared to healthy adults who didn’t take PQQ (blue bars). These findings weren’t found in younger adults (Young); however, pooling the groups together (All) unveiled significant results after 12 weeks.

The Cognitrax analysis included other cognitive parameters like cognitive flexibility, processing speed, and executive speed. Cognitive flexibility pertains to the ability to respond to new changes in instructions, processing speed relates to how fast one processes information, and executive speed entails understanding and making decisions about rules and concepts. Interestingly, cognitive flexibility and executive speed significantly improved in young but not old adults with eight and 12 weeks of supplementation. These data suggest that while PQQ didn’t significantly improve memory in younger adults, it enhanced other cognitive processes, namely, cognitive flexibility and executive speed.

(Tamakoshi et al., 2023 | Food & Function) PQQ improves other cognitive parameters in younger adults A) Cognitive flexibility improved in younger (Young) adults at eight and 12 weeks of PQQ supplementation. B) Processing speed significantly improved at eight weeks for younger adults (Young) who took PQQ but not at 12 weeks. C) Executive speed was enhanced at eight and twelve weeks of taking PQQ in younger adults (Young). Asterisks denote significant differences between adults who took PQQ (red bars) and those who didn’t take PQQ (blue bars).

“Our research is expected to expand the area where PQQ is used as a functional food from the elderly to all generations,” say Ikemoto and colleagues.

PQQ Mildly Enhances Most-Utilized Cognitive Dimensions

Cognitive function changes as people age. Younger people purportedly rely more on cognitive flexibility and executive speed. When we get older, our reliance on verbal and visual memory may grow. In that light, the data suggest that PQQ may slightly enhance the most utilized cognitive parameters for the two age groups.

Future studies should examine whether these cognitive dimensions continue improving over longer timeframes with PQQ supplementation. Future work could also examine how combining PQQ with other cognition-enhancing nutraceuticals may improve its effects.