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Our sense of smell changes as we age

  • Article by: Stacey Burling
  • Philadelphia Inquirer
  • July 26, 2014 - 3:00 PM

Food can be one of those unexpected flash points of late life.

Grandma may say she’s never hungry or that the only things that taste good are salty foods such as French fries. Grandpa may lose control over his sweet tooth, living on Tastykakes and ice cream.

The rest of the family worries that poor nutrition will make their elders’ already tenuous health even worse and hasten death. So, in frustration and fear, they chide or tempt loved ones to change their habits. Often, they learn what stubborn means.

“It is extremely distressing,” said Louisa Miceli, a nurse with the Visiting Nurse Association of Greater Philadelphia who has heard about eating problems in many a home. “Eating is such an emotional thing.”

Because metabolism slows and activity declines, it’s normal for elderly people to want less food. But our sense of smell — which is what contributed most of what we think of as flavor — falls apart as we age.

According to research by Richard Doty, director of the University of Pennsylvania’s Smell and Taste Center, ability to smell peaks by age 40. It’s all downhill from there, with the slope growing sharply steeper after 60. Sixty percent of people between 65 and 80 have major olfactory impairment. More than 80 percent do after 80.

Men are more impaired than women, and smokers fare worse than nonsmokers. Alzheimer’s and Parkinson’s diseases are also associated with problems with sense of smell. Some medications cause trouble, too.

Older people can also have distortions of taste that make everything — even water — taste salty or give foods a sour or bitter taste, Doty said. In cacosmia, one of the more alarming problems, foods take on a fecal flavor.

What you’re able to “taste” when your sense of smell goes are only the five basic flavors: salty, sweet, bitter, sour, and umami, a savory meaty taste. But subtle differences are gone. This explains the attraction of salt and sugar to the elderly.

How much to restrict salt and sugar is a question for a person’s doctor. Some doctors and nursing homes have loosened restrictions, especially for the oldest patients. They have concluded that weight loss in this population is a bigger danger than ice cream and cookies.

Still, most experts agree that good nutrition still matters. “You are what you eat, at any age,” said Carol Lippa, who studies Alzheimer’s disease at Drexel University.

© 2014 Star Tribune