The Fragrant Connection Between Our Sense of Smell and Aromatherapy
- Layecha Fidahoussen
- Apr 15
- 4 min read
As Ramadan comes to an end, the scent of fresh henna (a temporary form of body art) on my hands brings back a flood of memories from home. It's been three years since I’ve spent Eid away from Madagascar, and the smell of henna instantly takes me back to the many Eid eves I’ve spent with my sister and mom; they would take me to the mosque so we could apply henna together.
I’m Layecha Fidahoussen. I currently work as a research assistant at the Psychoimmunometabolix & Interaction with the Environment (PIXIE) Lab at King’s College London. For some time, I’ve been fascinated by how certain smells can bring me joy, sparking memories and emotions. This curiosity led me to delve deeper into our sense of smell and its profound connection to our experiences.
Has the smell of freshly baked cookies brought you back to your grandma's home from last autumn? Or perhaps the sweet fragrance of a perfume reminded you of a summer in Greece? On the flip side, maybe there’s a less pleasant memory, like the foul odour you encountered on the tube, which made you rethink your use of public transport.
Our sense of smell has a unique way of evoking memories, specifically autobiographical experiences, which are a collection of events throughout life that constructs one’s identity. It’s a strong cue that may trigger emotionally charged memories that bring back scenes from the past. This phenomenon is referred to as the “Proust Effect,” which stems from a well-known tale written by Marcel Proust at the beginning of his novel (Swann’s Way) where he describes the taste of a Madelaine cake dipped in a cup of tea which triggers the remembrance of a long forgotten memory.
The olfactory system plays an important role in detecting and recognising odours, and it’s particularly involved in sending signals to the brain. In regions such as the amygdala and hippocampus, which are associated with processing emotions and memory. This enables us to experience, process, and remember smells.
Now, think of all the times you've walked into a bakery and been greeted by the warm smell of bread or pastries baking in the oven, or perhaps the rich smell of brewed coffee made for the person next in line. When you smell a new perfume, like you experience new events or learn new things, smelling new things expands our palette. Scientifically, new smells modify to adapt and change the neural connections in the olfactory bulb, which is an area of the brain responsible for processing smell signals. This allows us to recognise this scent over time.
Now that we’ve established a good understanding of our sense of smell. I’ve noticed that essential oils (such as lavender and chamomile) have gained significant popularity for their potential benefit to help with issues from stress, sleep problems to sore throats. But do they actually work?
This form of healing refers to aromatherapy, a form of holistic therapy. Essential oils are extracted from various parts of plants through methods such as steam distillation, cold pressing, or solvent extraction. They are used in aromatherapy by either diffusing them into the air, applying them to the skin, or inhaling them directly as a complementary healing method to handle certain symptoms or promote well-being.
Some essential oils are known for their unique healing targets that can help promote physical and emotional well-being. An example of this is lavender. Lavender is known for its calming effects, which can soothe headaches and promote relaxation. It is known to reduce stress and anxiety. For centuries, aromatherapy has been used for therapeutic purposes, either in the form of cooking or medicine. The fragrances were used in various settings, from religious ceremonies to incorporation into fine remedies.
When you inhale essential oils, these molecules move up your nose, and in response, the olfactory receptors, which are specialised cells, send these signals to the brain through the olfactory nerve. As mentioned previously, they are sent to regions of the brain such as the amygdala and hippocampus. The brain then releases hormones such as serotonin, endorphins, and dopamine, which as known to regulate your mood, sleep, and digestion. Furthermore, it stimulates physiological responses, which can potentially increase our heart rate, blood pressure, breathing, and brain wave activity.
A recent study investigated how wearing rose scent on clothing for a month might impact brain structure. MRI scans were taken before and after to measure changes in grey matter, which is the part of the brain responsible for processing and decision-making. The researchers concluded that continuous inhalation of rose essential oil increased grey matter, especially in the posterior cingulate cortex (PCC). This finding could have potential implications for preventing dementia, as people with Alzheimer's disease (AD) often have reduced grey matter in the PCC. Since this study shows that rose essential oil can increase grey matter in this area, it raises the possibility that regular exposure to essential oil may help prevent brain shrinkage and serve as a potential preventive measure for dementia.
Furthermore, in a recent review, it was concluded that Lemon balm may help manage symptoms such as sleep disturbances, anxiety, and low mood, thus improving quality of life. The way it helps to do this is by its involvement in several biological pathways in the brain, like the GABAergic pathway, which makes use of a chemical called GABA (a neurotransmitter) to inhibit overactivity in the brain, leading to a calming effect. Another pathway is involved in the cholinergic pathway, which is crucial for processes related to attention, memory, and cognitive functions.
While research suggests aromatherapy may offer potential benefits, there's still much to discover. Our sense of smell plays a significant role in enhancing experiences and triggering memories, sometimes bringing forgotten events back to mind. It's a fascinating concept!
So, the next time you see an ad or commercial claiming that ylang-ylang essential oil can boost your self-esteem, remember to take it with a grain of salt and think of it from a scientific perspective.