Taste helps all of us recognize when food is good or bad. When an elderly person loses taste, it can cause a loss of appetite, weight loss, poor nutrition, weakened immunity, and even death.
Normal taste occurs when molecules released by chewing or the digestion of food stimulate special sensory cells in the mouth and throat. These taste cells, or gustatory cells, send messages through three specialized taste nerves to the brain, where specific tastes are identified. Damage to these nerves following head injury can lead to taste loss.
The taste cells are clustered within the taste buds of the tongue and roof of the mouth, and along the lining of the throat. Many of the small bumps that can be seen on the tip of the tongue contain taste buds. At birth, we have about 10,000 taste buds scattered on the back, side, and tip of the tongue.
After age 50, we may start to lose taste buds. We can experience five basic taste sensations: sweet, sour, bitter, salty, and umami, or savory. Umami was discovered by a Japanese scientist in the early part of the twentieth century. It is the taste of glutamate, a building block of protein found in chicken broth, meat stock, and some cheeses. Umami is the taste associated with MSG (monosodium glutamate) that is often added to foods as a flavor enhancer.
The five taste qualities combine with other oral sensations, such as texture, spiciness, temperature, and aroma to produce what is commonly referred to as flavor. It is flavor that lets us know whether we are eating an apple or a pear. Many people are surprised to learn that we recognize flavors largely through our sense of smell. Try holding your nose while eating chocolate. You will be able to distinguish between its sweetness and bitterness, but you can't identify the chocolate flavor. That's because the distinguishing characteristic of chocolate is largely identified by our sense of smell as aromas are released during chewing.
Food flavor is affected by a head cold or nasal congestion because the aroma of food does not reach the sensory cells that detect odors. A distorted sense of taste can be a serious risk factor for heart disease, diabetes, stroke, and other illnesses that require sticking to a specific diet. When taste is impaired, a person may change his or her eating habits. Some people may eat too little and lose weight, while others may eat too much and gain weight.
Many older people believe that there is nothing they can do about their weakened sense of taste. Depending on the cause of your problem, your doctor may be able to suggest ways to regain your sense of taste or to cope with the loss of taste. In many cases, the loss of taste turns out to be a loss of smell. If you think you have a problem with your sense of taste, see your doctor.