Rosemary -- the fragrant herb hailed for its ability to ease itchy scalp and soothe muscles -- could also have big brain-boosting benefits, a new study suggests.
Researchers from Northumbria University in the United Kingdom found that the amount of 1,8-cineole, a main chemical in rosemary oil, in the blood is linked with brain performance. Their work was published in the journal Therapeutic Advances in Psychopharmacology.
The finding "opens up the doorway for us to explore other odors and how they affect people," Dr. Alan Hirsch, director of the Smell and Taste Treatment and Research Foundation in Chicago, who was not involved in the study, told WebMD.
The researchers exposed 20 people to different levels of rosemary oil aroma, and then took blood samples to see how much of the 1,8-cineole each person absorbed. Then, the participants took speed, accuracy and mood tests to see if the rosemary oil had any effects.
They found that the more 1,8-cineole in the bloodstream of the person, the better the person's performance on both the speed and accuracy tests. Researchers also noted a small effect on mood.
"This compound is present in rosemary but has not previously been demonstrated to be absorbed into blood plasma in humans," study researcher Dr. Mark Moss told MSNBC. "It is our view that the aroma therefore acts like a therapeutic drug, rather than any effects being a result of the more sensory properties of the aroma."
However, Christy C. Tangney, PhD, of the Rush University Medical Center in Chicago, told WebMD that the results should be regarded as preliminary, as more research is needed to show that it's really the rosemary aroma that is providing the cognitive benefits.
This isn't the first research to link rosemary scent with memory. A 2003 study in International Journal of Neuroscience, also conducted by the researchers at the University of Northumbria, showed that rosemary is linked with "an enhancement of performance for overall quality of memory and secondary memory factors," though it was also linked with a decreased memory speed compared to the control group in that study.