This is a medical question of type : information 
 What is (are) Problems with Taste ? 
 Taste, or gustation, is one of our most robust senses. Although there is a small decline in taste in people over 60, most older people will not notice it because normal aging does not greatly affect our sense of taste. Problems with taste occur less frequently than problems with smell. How Our Sense of Taste Works Our sense of taste, along with our sense of smell, is part of our chemical sensing system. Normal taste occurs when tiny 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, sides, and tip of the tongue. After age 50, we may start to lose taste buds. Five Taste Sensations We can experience five basic taste sensations: sweet, sour, bitter, salty, and umami, or savory. Umami is the taste we get from glutamate, a building block of protein found in chicken broth, meat stock, and some cheeses. Umami is also the taste associated wtih 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. Flavors and the Sense of Smell 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. More information on this topic can be found in the topic Problems With Smell  Smell and Taste Closely Linked Smell and taste are closely linked senses. Many people mistakenly believe they have a problem with taste, when they are really experiencing a problem with smell. It is common for people who lose their sense of smell to say that food has lost its taste. This is incorrect; the food has lost its aroma, but taste remains. In older people, there is a normal decline in the sense of smell and the taste of food shifts toward blandness. This is why people often believe they have a taste problem. When Taste is Impaired Problems with taste can have a big impact on an older person's life. Because taste affects the amount and type of food we eat, when there are problems with taste, a person may change his or her eating habits. Some people may eat too much and gain weight, while others may eat too little and lose weight. A loss of appetite, especially in older adults, can lead to loss of weight, poor nutrition, weakened immunity, and even death. Taste helps us detect spoiled food or liquids and it also helps some people detect ingredients they are allergic to. A problem with taste can weaken or remove an early warning system that most of us take for granted. A distorted sense of taste can be a serious risk factor for illnesses that require sticking to a specific diet. Loss of taste can cause us to eat too much sugar or salt to make our food taste better. This can be a problem for people with such illnesses as diabetes or high blood pressure. In severe cases, loss of taste can lead to depression. Taste Problems Are Often Temporary When an older person has a problem with taste, it is often temporary and minor. True taste disorders are uncommon. When a problem with taste exists, it is usually caused by medications, disease, some cancer treatments, or injury. Many older people believe that there is nothing they can do about their weakened sense of taste. If you think you have a problem with your sense of taste, see your doctor. 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.