The sense of taste also known as gustation just like any other sense is very important in making food choices. Aside from helping to choose the foods of desirable flavors, it also helps to determine spoiled food. Several factors affects how one perceives taste. These include smell, texture of food, temperature of food, pregnancy, obesity, hunger, age and ability to activate the pain receptors like in the case of spicy foods. In the determination of the taste/flavor of food, the olfactory system plays an important role. This is because your sense of smell is somehow linked with your sense of taste. This is evident when you may have tasting difficulties whenever you have cold.
The human taste senses is a complicated and important sensory system. This complicated scientific process starts with the tongue. The tongue is a muscular organ located in the mouth that aids with swallowing, tasting and chewing. The tongue is made up of papillae- tiny raised protrusions that gives it a rough surface. These papillae houses the taste buds. The taste buds are made up of two types of cells. The supporting cells which form the outer envelope of the taste buds and the gustatory cells which occupy the central areas of the taste bud. The gustatory cells are also known as the chemoreceptors - these are specialized sensory receptor cells which converts a chemical substance to a biological signal. The human tongue has about 2000 – 10,000 tastes buds and these have a lifespan of about 10 days. Each taste bud has about 50 -150 taste receptor cells.
Mechanism of taste
The process of tasting requires the central nervous system and the brain. This is because it involves sending biological signals from the point of perception (the tongue) to the brain. The human body is able to detect 5 basic tastes. These are sweet, sour, bitter, umami and salty. In some cases the basic tastes are extended to seven to include “cool” and “hot”.
When food molecules enter the mouth, the tastants (water – soluble substance that activates the taste receptor cells) present in the food are picked up by the microvilli (taste hairs) present on the taste buds. The tastants causes the depolarization of the of the taste cells through a series of multiple pathways. The depolarized taste cells release neurotransmitters that stimulate the neurons that travel in the cranial nerves VII, IX, and X. Through a series of complex systems taste information is sent to the gustatory cortex which allows us to distinguish between tastes. The information that is transferred in this pathway is mostly for the differentiation of the basic tastes. Flavor which is a little complicated is developed by this taste information and information from the olfactory.
The sense of taste is not stable throughout the lifetime of humans. People lose their taste perception as they age. By the age of 20, half of your taste would be gone. By age 60, you may find it difficult to distinguish between sweet, sour, salty and bitter since your tastes buds would have reduced significantly.
Taste disorders
The most common taste disorders are hypoageusia and ageusia. Hypoageusia is a taste disorder in which the body has reduced ability to taste sweet,sour,salty,bitter and umami and ageusia is a the inability to detect any tastes. Ageusia is very rare and is mostly confused with the loss of smell (anosmia). Another form of taste disorder is dysgeusia. This is a situation where a person’s taste perception is altered and as such everything they taste seems sweet, sour, bitter or metallic. This condition is sometimes accompanied by a painful burning sensation in the mouth.
The causes of taste disorders include head injury, poor oral hygiene, radiation therapy for cancers to the head and neck, cold or flu and hormonal changes among others. Some taste disorders can be treated totally, others partially and others may not be treatable.
Your ability to taste foods won’t be perfect throughout your lifetime. So at every stage of your life appreciate and pamper your taste buds.