The effects of rosemary oil on memory
I watched a programme recently on Channel 4 and was interested to see that in part of the show, an experiment was conducted live on air regarding the effects of rosemary essential oil on short-term memory and cognition. Two groups were identified and each given tasks to remember a series of common but disconnected words being shown on a computer screen. Neither group were told that one group would be exposed to the smell of rosemary oil via a vaporiser throughout the experiment, whereas the control group would not be exposed to any scent. Afterwards, each group were asked to remember words from the former sequence. In conclusion, the experiment clearly demonstrated that exposure to the scent of the rosemary oil considerably enhanced the memory of those in the experimental group as opposed to those in the control group. The scientific explanation given was as follows:
“Acetylcholine is one of the neurotransmitters in our brain and its job is to deliver information between neurons which form memory. There is a compound in rosemary that preserves and strengthens these transmitters making memory stronger and recall easier.”
How essential oils can alter your cognitive performance
In the BBC article ‘What does Rosemary do to your Brain?’ Dr Chris Van Tulleken puts forward similar conclusions based on another experiment as to why rosemary is effective for promoting recall. A team at Northumbria University in London recruited sixty volunteers to test the effects of rosemary oil and lavender oil against a control group but without them being aware of the nature of the experiment. The volunteers were assigned to a room infused with either rosemary essential oil, lavender oil or no aroma and then given a test using word puzzles and other memory games designed to assess their recall. The results showed that the group exposed to the rosemary oil did statistically significantly better in the memory test than those in the control group, but lavender caused a significant decrease in performance. Dr Chris Van Tulleken then asks: ‘Could lavender oil be sending the volunteers to sleep and decreasing their performance … how could vaporised essential oils possibly have this effect?’
“It turns out that there are compounds in rosemary oil that may be responsible for changes in memory performance… it may act in the same way as the drugs licensed to treat dementia, causing an increase in a neurotransmitter called acetylcholine. These compounds do this by preventing the breakdown of the neurotransmitter by an enzyme. And this is highly plausible – inhalation is one of the best ways of getting drugs into the brain. When you eat a drug, it may be broken down in the liver which processes everything absorbed by the gut, but with inhalation small molecules can pass into the bloodstream and from there to the brain without being broken down by the liver. As further confirmation, the team analysed blood samples and found traces of the chemicals in rosemary oil in the blood. The implications of this kind of research are huge…”
How essential oils can affect your brain wave patterns
The experiment concluded that the effects were measurable but modest and suggests that further research into some of the chemical constituents in essential oils may yield therapeutics and contribute to our understanding of memory and brain function in the future. This recent research further confirms studies outlined in my book ‘Aromatherapy and the Mind’. In a series of experiments measuring the effect of specific essential oils on brainwave patterns using an EEG (electroencephalogram) monitor, it was shown that different essentials can alter brain wave patterns quite significantly simply via inhalation. Using this monitor, an increase in alpha activity indicates a relaxing or soothing effect, whereas increased beta activity indicates increased levels of stimulation or attention. In these experiments, lavender, neroli, jasmine, rose, sandalwood, valerian, frankincense, chamomile and bergamot increased delta patterns, thereby slowing the mind’s mental chatter, being similar to brain wave patterns induced by a meditative state. On the other hand, rosemary, basil, black pepper, cardamom, clove, peppermint and lemongrass increased beta activity patterns, signifying increased alertness.
Further reading on this topic
Available as a kindle version.