This Is How Important Our Sense Of Smell Is When It Comes To Tasting Food

We all know the feeling when you catch a head cold and your nose is all blocked up. You can't breathe or smell all that well, let alone taste much of the foods that you're putting into your mouth. That's because being able to taste anything is hugely influenced by our sense of smell.

Foods exude aromas, which are comprised of a variety of molecules that make up cooking smells. When these enter your nose, they bind to proteins in the olfactory lining, called olfactory sensory neurons, which then send the information to the brain. Similarly, tastes are picked up by taste receptors on the tongue, firing that info to the brain. The brain then takes these inputs and, together with the "touch" experience (the information of what a food feels like, what its texture is, etc.), crafts your sensory perception of that food. It's rather more complex than that, including visual attraction to food and the context of our eating experience, but this gives a good overall understanding of how we perceive flavors.

But the tongue can only pick up the five basic tastes: sweet, salty, bitter, sour, and umami. It's the hundreds of odor receptors in our noses that fill in all the juicy details of the basic skeleton of overall flavor we perceive. In fact, it is believed that around 80% of our flavor experience comes from smell. So, if our sense of smell is impeded, the brain will get very little information, and we will get only the most basic experience of taste.

While there are approximately 100 to 200 known functional odor receptors in humans, some research has suggested that we can distinguish around 10,000 distinct odors. A change in the combination of molecules alters the message the receptors send to the brain, so it becomes far more plausible that further research indicates humans can detect closer to one trillion odors.

While the nose leads the pack in detecting odor molecules, the mouth also plays a role, specifically the passage between the throat and the nose. When we chew food, it releases volatile molecules, some of which travel up the throat to the olfactory receptors clustered in the area where the throat meets the back of the nose, which also houses olfactory sensory neurons that shoot info to the brain. If you have an inflamed throat and sinuses, the functionality of these receptors can be affected, because the inflammation blocks the odor molecules from reaching the sensory neurons.

But here's the jaw-dropper: Muscles, lungs, kidneys, and even blood vessels contain olfactory receptors that do behind-the-scenes work, detecting chemical changes in your body after you've eaten something. Taste receptors can also be found in some unexpected parts of the body, like the bladder. In this case, these detect chemicals in different foods, which trigger a specific response to the chemicals. So receptors assigned to detect sweet tastes, like those found in artificial sweeteners (which also contain the chemical saccharin), could cause the bladder muscles to contract, expelling more urine.