Problems with sense of smell become more common as people get older:
- Twenty four and a half percent (15 million) of Americans 55 years old or older have a problem with their sense of smell.
- Thirty percent of Americans between the ages of 70 and 80 have a problem with their sense of smell.
- Nearly a third of people over 80 have a problem with their sense of smell.
A person's sense of smell generally declines when he or she is over 60. Only about one to two percent of people under the age of 65 will experience some problem with their sense of smell. Women of all ages are generally better at detecting odors than men.
Smell that declines with age is called presbyosmia and is not preventable. The sense of smell, or olfaction, is part of our chemical sensing system, along with the sense of taste. Normal smell occurs when odors around us, like the fragrance of flowers or the smell of baking bread, stimulate the specialized sensory cells, called olfactory sensory cells. Olfactory sensory cells are located in a small patch of tissue high inside the nose. Odors reach the olfactory sensory cells in two pathways. The first pathway is by inhaling, or sniffing, through your nose. When people think about smell, they generally think of this pathway.
The second pathway is less familiar. It is a channel that connects the roof of the throat region to the nose. When we chew our food, aromas are released that access olfactory sensory cells through this channel. If you are congested due to a head cold or sinus infection, this channel is blocked, which temporarily affects your ability to appreciate the flavors of food.
Odors are small molecules that are easily evaporated and released into the environment and that stimulate these sensory cells. Once the olfactory sensory cells detect the odor molecules, they send signals to our brain, where we identify the smell and its source.
For most people, a problem with smell is a minor irritation, but for others it may be a sign of a more serious disease or long-term health condition.
When people have a problem with smell, they may experience either total or partial loss of smell. They can also sometimes think they smell bad odors that are not actually present. Total smell loss is relatively rare. However, a diminished sense of smell occurs more often, especially in older adults. A diminished sense of smell may be temporary and treatable with medication. People with smell disorders usually have problems appreciating the subtle flavors of food, and say that food is less enjoyable.
Smell and taste are closely linked in the brain, but are actually distinct sensory systems. True tastes are detected by taste buds on the tongue and the roof of the mouth, as well as in the throat region, and are limited to sweet, salty, sour, bitter, savory and perhaps a few other sensations.
The loss of smell is much more common than the loss of taste, and many people mistakenly believe they have a problem with taste, when they are really experiencing a problem with their sense of smell. A loss in taste or smell is diagnosed by your doctor using special taste and smell tests.
The sense of smell gradually declines in older people. This is normal. Many older people are not even aware that they have a problem with their sense of smell because the changes occur gradually over several years. They may not even notice that they are experiencing a loss of smell until there is an incident in which they don't detect food that has spoiled or the presence of dangerous smoke.
When smell is impaired, some people change their eating habits. Some may eat too little and lose weight while others may eat too much and gain weight. Either way, there may be a long-term impact on one's overall health. Loss of smell may also cause us to eat too much sugar or salt to make our food taste better. This can be a problem for people with certain medical conditions, such as diabetes or high blood pressure. In severe cases, loss of smell can lead to depression.