We’ve all been there—sick with a cold or flu, fatigued and needing a bite to eat. So you heat up some soup, take a sip, the warmth of it wraps around you like mama’s hug… then the disappointment hits as you realise you can’t taste a thing! Generally when our noses are blocked, we lose our precious senses of smell and taste. Suddenly, the joy of eating is gone, and boy, did we take our working nose for granted! Let’s delve into the science of why this happens.
The flavour of food doesn’t just involve the mouth but also the nose: these body parts are closely linked through the relationship of their receptors. Taste is therefore really the complex combination of smell and taste. Both the nose and the tongue detect chemicals in food, and this is what tells our brain the flavour of the food we’re eating. In fact, as much as 80% of our taste is related to smell!
We are able to taste thanks to the tastebuds on our tongue. Tastebuds are found in little bumps called papillae. They pick up the five main tastes: sweet, salty, sour, bitter and umami (aka savoury). Within these tastebuds there are sensory cells, also called ‘taste hairs’, which are connected to nerves. When we chew, proteins bind taste chemicals to these taste hairs for processing. On average, an adult has between 2000–4000 taste buds, with taste hairs that renew themselves weekly.
The nose knows
The sense of smell is also called olfaction. The inside of the nose is filled with olfactory receptor neurons (smell cells), which send information to the olfactory nerve. This nerve picks up the chemicals given off by food and tells the brain what food is being smelled. This assists in detecting the taste of foods. Fun fact: the sense of smell is the sense most closely associated with memory. Should a person’s olfactory system become compromised, such as during a cold/flu, the person may suffer from anosmia (the inability to process smell, and tastes).
Now, try blocking your nose with your fingers and eat something. The taste will be diminished, if not completely gone in some cases. This is also the case when you’re unwell: the olfactory mucosa becomes inflamed and obstructed (blocked by mucous/goo), which means the chemicals that contribute to smell and taste cannot go anywhere near the receptors that signal the olfactory nerve. Your taste buds are obviously still working, but even though there are thousands of them at work, they still don’t come close to what the nose knows!
What about when you’re on an airplane?
There’s a lasting stereotype that airplane food isn’t the best, no matter how gourmet the staff try to make it seem. For those that have tried airplane food, it may have tasted different or bland—definitely doesn’t hit the same way it does on land. This is actually because of a few different factors. At 30 000 feet in the air, the cabin pressure is low, the air is dry and there’s that annoying background noise of chatter, as well as the roaring engine of the plane. All of these things affect your smell and taste as your mouth and nose dry out and taste buds become ‘numb.’ The BBC reports that our ability to taste sweet or salty foods decreases in the air due to these effects. A 2011 study found that the background noise of a plane also has a massive impact on how much you enjoy your airline meal. Loud noises affect the ability to taste sweetness and saltiness. And similar to being in a very loud restaurant and eating, loud environments make people less likely to enjoy their food!
What’s music got to do with it?
We now know our sense of taste is linked to olfaction. To add to this, our perception of taste also depends on a whole bunch of other things including colour, expectations and even sounds! Similar to loud environments distorting our tastes, other studies have found that the music we listen to while eating can change our perception of what we are consuming! A 2012 study showed that the emotional vibe of a piece of music can influence people’s perceptions of red or white wine. Another study found that listening to a lower pitched soundscape helps to emphasise bitter notes in a bittersweet toffee while listening to a higher pitch soundscape brought out its sweetness. The psychology and neuroscientific explanations for these phenomena are still unclear and more research is required to further investigate the links between sounds, tastes and our brain!
I know for sure I won’t be taking something as ‘simple’ as tasting food for granted again! There are so many different senses and organs involved and it’s amazing that the brain has a massive say too. Could it be a simple case of mind over matter? Before you eat anything, expect it to taste amazing and perhaps it will be so!