As aging progresses, senses (vision, hearing, taste, smell, touch) may become less acute. The most dramatic sensory changes with age affects vision and hearing but all the senses can be affected by aging.
Visual impairment is the most common sensory problem of older adults. About 95% of individuals age 65 and older report wearing glassing or needing glasses to improve their vision. However, the effectiveness of glasses decreases with age. Those with a family history of eye disorders, diabetes or a diagnosed vision disorder such as glaucoma or cataracts should get more frequent checkups.
Hearing loss is very common with aging and is one of the most correctable yet often unrecognized problems. It contributes significantly to social isolation. About 25% of people between 65 and 74 years of age and 50% of people age 75 or older report difficulty hearing.
As aging progresses, the number of functioning smell receptors decreases and this increases the threshold for smell. It takes a more intense smell for it to be identified and differentiated from other smells. After the age of 50 the sense of smell decreases rapidly. By age 80, the sense of smell is reduced by about half. The lack of ability to smell spoiled food can lead to indigestion and food poisoning.
Taste also diminishes with age and older persons often complain that food doesn't taste as good as it used to. Some atrophy of the tongue occurs with age and this may diminish sensitivity to taste. Receptor cells for taste are found in the taste buds on the tongue and are replaced continuously. Other factors that contribute to changes in taste among seniors include poorly fitting dentures.
In later life, sense of touch and response to painful stimuli decreases. The actual number of touch receptors have decreases which results in a higher threshold for touch. The major concern a loss in touch sensitivity raises relate to personal safety. For example, older adults do not sense heat as quickly so they tend to have worse burns.
Failing eye sight, limited mobility and inability carry food and then cook it all interfere with a proper diet being consumed. Taste and smell sensitivities diminish with age and make eating less enjoyable.
Besides these, psychological, economic and social changes contribute to deterioration in nutritional status.