How Does Our Sense of Smell Change With Age?

When we think of sensory impairment in older adults, most of us think of problems with vision and hearing. This is understandable. Visual impairment and hearing loss can have a major negative impact on the physical, emotional and cognitive well-being of older adults. But as we grow older, we can experience changes in our sense of smell, as well.

“That Grandpa and Grandma aren’t as good at smelling as they once were is something that many can relate to,” say a team of experts from the University of Copenhagen. “And, it has also been scientifically demonstrated. One’s sense of smell gradually begins to decline from about the age of 55.” 

“The Copenhagen experts, headed by food scientist Eva Honnens de Lichtenberg Broge, recently conducted research that reveals something interesting: Our sense of smell doesn’t decrease evenly. “Our study shows that the declining sense of smell among older adults is more complex than once believed,” says de Lichtenberg Broge. “While their ability to smell fried meat, onions and mushrooms is markedly weaker, they smell orange, raspberry and vanilla just as well as younger adults. Thus, a declining sense of smell in older adults seems rather odor specific.”  

The causes of loss of smell

Smell loss has been in the news a lot lately. Early in the COVID-19 pandemic, doctors noted that a loss of smell was a noticeable symptom. Dr. Carl Philpott of the University of East Anglia (UEA) in the UK has studied this effect for months, and learned that while loss of smell due to a cold or allergies is caused by congestion, people with COVID-19 can usually breathe freely. The virus instead affects their central nervous system. The effect is usually temporary, but in some patients, long-term.

For years, Dr. Philpott has studied smell loss and treated patients who have smell disorders. He explains that loss of smell—called anosmia—can be a temporary condition, brought on by allergies, a cold, certain medications or medical treatments and, these days, COVID-19. But it might also be of long or permanent duration, being present at birth or caused by infections, injuries, tumors, problems with the bones of the nasal area or sinuses, or neurological conditions.

Dr. Philpott also describes a related smell disorder, parosmia, which alters the way things smell. “For people with parosmia, the smell of certain things—or sometimes everything—is different, and often unpleasant,” says Dr. Philpott. “So for example, someone with parosmia could sniff at a cinnamon stick, but to them it would smell like something horrible—perhaps rotten food, or worse.”

Loss of smell affects health and well-being

Impaired ability to smell affects quality of life in several ways:

Safety. Dr. Diego Restrepo of the University of Colorado School of Medicine warns that smell loss can keep seniors from detecting spoiled food, smoke, leaking gas or toxic vapors. He says this makes it especially important to keep smoke alarms in good working order, and to take extra precautions when cooking with natural gas.

Nutrition. Dr. Restrepo cautions that as seniors lose their sense of smell, they are at greater risk of malnutrition, since food is appetizing due to smell as much as to taste. (People of any age can test this by evaluating the appeal of hot coffee and a fresh-baked cookie while they are suffering from a head cold.) He recommends that seniors adjust the seasoning in their food and make food more texturally and visually appealing.

Brain health. Research on the relationship between sensory loss and brain health has mostly focused on vision and hearing loss—and the connection is quite clear. Yet experts talking about the connection between dementia and loss of smell most often focus exclusively on anosmia as an early symptom, whereas loss of smell also contributes to a cognitive load, and stress that is bad for the brain. It can be both a cause and an effect.

Reminiscing. “The inability to link smells to happy memories is also a problem,” reports the UEA team. “Bonfire night, Christmas smells, perfumes and people—all gone. Smells link us to people, places and emotional experiences. And people who have lost their sense of smell miss out on all those memories that smell can evoke.”

Emotional well-being. The UEA team noted that smell is intertwined with relationships, parenting, even a person’s confidence in their hygiene. They found that loss of smell can lead to “a diverse range of negative emotions including anger, anxiety, frustration, depression, isolation, loss of confidence, regret and sadness.”

Dr. Philpott says that historically, clinicians haven’t taken smell loss very seriously—but they should. He reports that his patients often had previously experienced a lot of negative, unhelpful interactions with health care providers. “Those that did manage to get help and support were very pleased—even if nothing could be done about their condition,” he reports. “They were very grateful for advice and understanding.”

Dr. Philpott has been conducting research on “smell training”—therapies to help the brain relearn the ability to smell, which seem to work particularly well on older patients. Prevention is important, as well. While smell loss diminishes naturally with age, older adults can avoid certain things that hasten the loss, such as poor diet, infections, pollution and other toxic substances in the air, and sleep disorders such as sleep apnea.

The information in this article is not intended to replace the advice of your health care provider. If you are experiencing changes in your sense of smell, report that to your doctor.

Source: IlluminAge with information from the University of Copenhagen, the University of East Anglia and the University of Colorado Anschutz Medical Campus