From sweet bread to champagne: how the aromas of Christmas impact the brain

The Christmas holidays are a festival of smells, tastes, sights, sounds and textures. The five senses help us fully immerse ourselves in this time of year through meals, Christmas carols, fireworks and pyrotechnics, the candles that adorn our table …

In one way or another, the truth is that each of us has our rituals for the holidays, rituals that we share with family and friends. It is also a time of nostalgia. Before it was thought that nostalgia was part of a depressive picture or some affective disorder. Today it is known that this is not the case and that it can be triggered by external stimuli. One of them, the one that concerns us today, are smells.

In this association between nostalgia and smells, the main protagonist is a brain structure called the hippocampus. Our brain “seahorse” is part of the limbic system, which is the place where the memory is stored. It works as a “library” of our memories “.

Smell is the sense that is most unknown, perhaps because it is the least widespread, but science studies it. American scientists Richard Axel and Linda Buck, pioneers in their work, received the Nobel Prize in Medicine in 2004 for the discovery of olfactory receptors and the organization of the olfactory system.

This powerful sense has unique properties: 80% of the flavor we perceive in each meal is thanks to smell. This has happened to all of us to evoke a memory by smelling a meal. Who has not felt like a child again when, through some window, the smell of grandmother’s pasta or mother’s sweets arrives.

Sometimes these memories are not pleasant. If you had a traumatic experience, such as living a fire, the smell of burning will trigger unpleasant sensations. Both of them trigger behaviors: It is likely that we remain calm in the place where we smell the smell that refers us to pleasant family memories and that we tend to move away from those places where we perceive odors that are unpleasant to us.

So we can say that we have a surveillance and alert system in our brain, which conditions our behavior according to the smells we perceive. However, there are still people with smell disorders who are on the pilgrimage in search of solutions to their problem.

Smell is as old in evolution as life on earth. The human being, already from his quadruped position, knew his environment thanks to smell: we had our nose very close to the floor. As we come to an upright posture, we move away from the ground and other senses such as hearing and sight begin to matter. Our beloved smell begins to lose ground next to sight and hearing.

The good news is that olfactory neurons (nerve cells) have the ability to constantly renew themselves throughout life: it is the only neuronal population where this happens.

This is important to take into account because it is also true that smell is lost with age and, sometimes, by diseases of the nose and paranasal sinuses, by the action of viruses and bacteria that damage the olfactory tract, by cigarette smoke or by inhaling certain toxic substances that are suspended in the air.

For all this, it is very important to consult as soon as a problem is perceived with this valuable sense. The way we smell has a strong genetic component: 5% of the human genome is dedicated to smelling!

Going back to this time of year the holidays “smell” of many things: the orange blossom water used to prepare sweet bread, marzipan for nougats, apple cider and the perfume of the loved one in the embrace of the toast. After twelve o’clock, the powder from the fireworks also seeps into our noses. Let’s face these holidays with our senses on the surface.

* Dra. Stella Maris Cuevas (MN: 81701) is an otolaryngologist – Expert in smell – Allergist. Former President of the Association of Otolaryngology of the City of Buenos Aires (AOCBA)

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