Over the course of history, people have tried to harness the power of smell. Avicenna sniffed human excrement to diagnose illnesses and Hippocrates is thought to have used fragrant plant fumigations to rid the plague.
It wasn’t until recently that the therapeutic use of scents started to gain momentum. Aromatology, or aromatic science, hypothesizes that smells can produce a significant effect on human mood and health. Its popularity has prompted research into the prospect of using scents to treat diseases. Countries such as France have even integrated aromatherapy into conventional medicine. But how much truth is there to aromatic science?
Rachel Hertz, a visiting professor at Brown University, believes that “peppermint may help you feel more alert and think more clearly.” A study speculates that it may even boost physical performance, allowing people to endure a more rigorous workout. Recent studies have found that the volatile substances found in grapefruit suppress food consumption and increase plasma glycerol concentration, an indicator of fat breakdown. For enhanced cognitive performance, cinnamon is speculated to improve mental processes and mood. Current research dictates that smelling cinnamon increases attention, memory, and visual-motor speed. This finding has generated further research into its healing potential for cognitive deterioration.
The scent of coffee has been found to activate genes that counteract the physical and emotional consequences of sleep deprivation. In a study carried out at Seoul National University, researchers took caged rats and immersed them in an inch of water to keep them awake. The rats were divided into two groups: one was exposed to the aroma of coffee, and the other placed in a fragrance-free setting. Subsequent brain analysis found the caffeinated group exhibited higher gene expression for antioxidant function, resistance to cell damage, anxiety control, cellular communication, and metabolism.
Lavender may be an effective way to combat stress and promote relaxation. The chemical linalool found in the lavender plant is what scientists believe may be responsible for this calming effect. Through psychopharmacological in vivo analysis, it is shown to have a sedative effect on the central nervous system. Research published in the journal Neurochemical Research reports an “inhibitory effect on [the main excitatory neurotransmitter in mammals] in rat[s].”
Scientists aren’t completely convinced. The olfactory system is highly complex and much research is still needed to comprehend the underlying architecture and mechanism by which it works. So far, we know that chemical molecules dissolve through receptor cells in the epithelial membrane. This creates an electrical signal, which is transmitted to the brain, stimulating the release of neurochemicals.
According to William MacKay, a physiology professor at the University of Toronto, “virtually all of the aromatherapy claims [remain] scientifically untested.” However, he also notes that “the olfactory system has far more receptor proteins available than any other sensory system. Furthermore, [olfaction alone is the only sense] with direct access to the limbic network of the brain, the part that mediates emotional experience and mood.”
Perhaps there’s more to smell than meets the nose after all.
