Scents, Memories, and Your Mood

Why Do Some Scents Evoke Memories?

​Have you ever caught a whiff of a scent that unexpectedly took you back to a moment in time from your childhood? For me, when I smell chlorine it takes me back to carefree days at the local pool. I love the fragrance even today for that reason. I was talking with a friend who said that the smell of rubbing alcohol was reminiscent of pleasant visits to the pediatrician as a child. Many dislike the scent, but for her it evokes memories of nurses in clean white dresses and a peaceful feeling of everything being clean and in order. Isn't it interesting how our sense of smell is so closely connected with our memories? Last month we chatted about the fragrance pyramid and how fragrances are layered based on the type and size of the scent molecules. This month I thought we could continue our chat about fragrances and how they can evoke memories and affect our moods.
The answer to our question lies in how our brains process fragrances, and this is part of the limbic system in the brain. There's some really interesting tidbits on how this process works!

​Our sensory input (including our sense of smell), our memories, and our emotions are all processed in the part of our brain called the limbic system, which sits on top of the brain stem. Scientists are still discussing exactly what structures are included in this system, but they generally agree that it includes at least the hypothalamus, the amygdala, the thalamus, the hippocampus, and the olfactory bulb (scent receptors). Honestly, I'm not going to explain all those terms to you because the details are beyond my comprehension. But here's the interesting part. Our sense of smell is processed differently than all our other senses. All of our senses except for smell are processed through the thalamus; so sight, sound, touch, and taste are all relayed through the thalamus. But input from our sense of smell bypasses the thalamus. Scents have a private relay system straight from the olfactory bulb to other parts of the brain! No wonder the connection between scents and memories is so strong! Here's an over-simplified diagram of how this works.

​Often, when you have a childhood memory associated with a scent, it was formed before you were ten years old. Usually it is a perceptive memory, not a specific memory. In other words, the scent is linked to a general feeling more than a detailed account of an specific event. This memory is deeply embedded in your long-term memory and connected to your emotions, due to how scents are processed by the limbic system. 
Because our sense of smell is so strongly connected with our memories, emotions, and even our hormones, we can use the power of scent to boost our moods when we need a pick-me-up, thanks to our limbic system! Even though we have different memories associated with certain fragrances, there are some generalities that can be made about scents and our moods. For example, we've all heard about how lavender is calming and promotes rest. Here's a chart of some common fragrances, and how they can positively affect our moods.

Next time you need some added energy for a task, try adding some grapefruit, orange, or lemon scents to your environment. Or if you'd like to uplift your mood and increase your confidence, try a floral fragrance! And you don't need to save a woodsy pine scent for Christmas. It can bring you joy all year!

Also, did you know that the limbic system is supported partly by zinc and thiamine (vitamin B1)? If we lack these essential nutrients it can affect how our limbic system functions. Maybe you've heard about the connection between losing your sense of smell and a zinc deficiency. Zinc is an important part of building our immune system as well. Not only is zinc necessary for our immune system, but it also strengthens our limbic system!  Eating foods rich in thiamine and zinc can help boost your immune system and your limbic system -- this is a win-win!