Review calls for more studies on cinnamon and cognitive function
“This systematic review revealed that cinnamon and its components (eugenol, cinnamic acid, cinnamaldehyde, etc.) could affect memory and learning by decreasing amyloid plaque in the hippocampus and phosphorylation of tau-protein,” wrote researchers from Birjand University of Medical Sciences in Iran.
They attribute these brain-boosting benefits to cinnamon’s antioxidant, anti-inflammatory and anticholinesterase activity as well as neurotrophic effect, neural maintenance and insulin signaling improvement.
Cinnamon and its compounds
Cinnamon, from the inner bark of evergreen trees belonging to the genus Cinnamomum, has been used in herbal medicine for centuries from China to Egypt as remedy for respiratory, digestive and menstruation issues. Today, as supplement, it is also suggested as support for healthy glycemic response and blood pressure.
“Cinnamon is proven to have antioxidant properties and reduce inflammation through different pathways, such as the NF-kB pathway and reducing reactive oxygen species (ROS),” the researchers noted. They attribute the antiproliferative, anti-inflammatory and antioxidant effects to compounds including eugenol, cinnamic acid, cinnamaldehyde, syringic acid, tannins and catechins.
Cinnamon also contains a small amount of choline, an essential nutrient for the brain that produces the acetylcholine neurotransmitters, which in turn play a critical role in regulating memory, mood, muscle control and other functions.
Indications of potential brain benefits
The research team conducted a systematic review of 40 eligible studies selected from a total of 1,605 collected from the Web of Science, Google scholar, PubMed and Scopus databases between 2011 and 2021. They include five in vitro studies, 33 in vivo studies in rats, mice and the common fruit fly, and two clinical trials in adolescents and pre-diabetic older adults.
“One clinical study on adolescents showed a positive effect on memory using cinnamon chewing gum for 40 days, while the other reported no significant changes in memory using cinnamon administered orally (single dose/2 g),” the study reported.
Among the in vitro and in vivo studies, 16 used the cinnamon extract/cinnamon powder, while others administered a variety of cinnamon bioactives. The researchers concluded that the main outcome of most studies proved that cinnamon significantly improves cognitive function i.e. memory and learning.
“In vivo studies showed that using cinnamon or its components, such as eugenol, cinnamaldehyde and cinnamic acid, could positively alter cognitive function,” they wrote. “In vitro studies also showed that adding cinnamon or cinnamaldehyde to a cell medium can reduce tau aggregation, amyloid β and increase cell viability.”
Tangled tau proteins are associated with a range of neurodegenerative diseases, while the pathology of Alzheimer’s disease appears to be driven the production and extracellular plaque deposits of amyloid β peptide.
Call for further study
Acknowledging limitations across the collection of varied studies, the researchers call for larger studies and more clinical trials to evaluate the effects in humans.
“It is also beneficial that in vivo studies in this field propose the probable mechanism of cinnamon affecting the brain to specify the related pathways more precisely,” they added.