Loss of sense of smell can have serious consequences.
How to Preserve Your Sense of Smell
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Based on a study of nearly 2,000 people, our sense of smell declines as we age, similar to our loss in vision and hearing. About a quarter of Americans over the age of 50 suffer from olfactory dysfunction—a difficulty identifying odors—which climbs to more than half of individuals between the ages of 65 to 80 years of age, and about 80 percent in those over the age of 80. And, that was before COVID-19, which affected the smell of nearly 50 percent of sufferers. Typically it was temporary, but as many as 15 percent of non-hospitalized COVID survivors were still experiencing problems with the ability to smell three or months later––and there are cases of it lasting for years.
As anyone with even a simple head cold can tell you, when you lose your sense of smell, you lose much of your sense of taste as well. Between 75 to 95 percent of what we think of as taste may actually be smell. This was all too vividly illustrated by the case of Algerian War soldiers whose tongues had been cut out remarkably reporting little loss of food and drink flavor sensation.
But hey, if loss of smell leads to loss of taste, think of all the weight loss! That was apparently the thought behind the development of a “novel nasal device,” gag-inducing silicone tubes you stick in your nostrils to cordon off your smell receptors. Researchers recorded a drop in preferences for sugary foods and beverages along with weight loss, but only among younger adults––presumably because the sense of smell of the older adults was already impaired. Making everything taste bland may help you skip a few doughnuts, but the flip side is that people with smelling difficulties tend to add more salt.
Older individuals were found to require two to three times more salt than those who were younger to achieve the same salty taste. It’s no wonder that the lifetime risk of developing high blood pressure may exceed 90 percent.
What can we do to preserve our sense of smell? Ambient air pollution is associated with olfactory dysfunction––thought to explain why nasal biopsies from residents of Mexico City, living and dead, showed more lesions and inflammatory changes than those living in low-pollution cities. We may not have a choice where we live, but there is definitely a direct source of air pollution tied to loss of smell we can all choose to avoid: cigarette smoke.
Smell loss can have serious consequences, for instance, missing a gas leak, smoke, or spoiled food. (If you have lost your sense a smell and use natural gas, please consider buying a gas detector). But, in terms of direct disability, most people who are affected don’t even to seem to be aware their smell is impaired, even when asked directly. Nearly eight out of 10 elderly individuals with smell loss thought they had normal smell sensitivity.
Hearing loss, however, is considered a major cause of global disability, ranking among the top chronic conditions affecting older adults. For far too long, though, as a National Academy of Medicine report put it, hearing loss has been “relegated to the sidelines of health care.” For those interested, check out my video series that starts with Age-Related Hearing Loss Is Not Inevitable, then a supplement shown to help, and ending with a video on dietary changes that can help, too.
Please consider volunteering to help out on the site.
- Doty RL, Shaman P, Applebaum SL, Giberson R, Siksorski L, Rosenberg L. Smell identification ability: changes with age. Science. 1984;226(4681):1441-1443.
- Desiato VM, Levy DA, Byun YJ, Nguyen SA, Soler ZM, Schlosser RJ. The prevalence of olfactory dysfunction in the general population: a systematic review and meta-analysis. Am J Rhinol Allergy. 2021;35(2):195-205.
- Saniasiaya J, Islam MA, Abdullah B. Prevalence of olfactory dysfunction in coronavirus disease 2019 (COVID-19): a meta-analysis of 27,492 patients. Laryngoscope. 2021;131(4):865-878.
- O’Byrne L, Webster KE, MacKeith S, Philpott C, Hopkins C, Burton MJ. Interventions for the treatment of persistent post-COVID-19 olfactory dysfunction. Cochrane Database Syst Rev. 2021;7(7):CD013876.
- Fernández-de-Las-Peñas C, Palacios-Ceña D, Gómez-Mayordomo V, et al. Prevalence of post-COVID-19 symptoms in hospitalized and non-hospitalized COVID-19 survivors: A systematic review and meta-analysis. Eur J Intern Med. 2021;92:55-70.
- Deng YK, Shi KT, Liu Z, Zeng M. Persistent olfactory dysfunction 2 years after onset of COVID-19. J Infect. 2023;86(2):154-225.
- Spence C. Just how much of what we taste derives from the sense of smell? Flavour. 2015;4(1):30.
- Spence C, Youssef J. Aging and the (Chemical) senses: implications for food behaviour amongst elderly consumers. Foods. 2021;10(1):168.
- Dicker D, Beck A, Markel A, et al. Weight loss, dietary preferences, and reduction in the sense of smell with the use of a novel nasal device. Obes Facts. 2020;13(5):473-486.
- Stevens JC, Cain WS, Demarque A, Ruthruff AM. On the discrimination of missing ingredients: aging and salt flavor. Appetite. 1991;16(2):129-140.
- Vasan RS, Beiser A, Seshadri S, et al. Residual lifetime risk for developing hypertension in middle-aged women and men: The Framingham Heart Study. JAMA. 2002;287(8):1003-1010.
- Ajmani GS, Suh HH, Pinto JM. Effects of ambient air pollution exposure on olfaction: a review. Environ Health Perspect. 2016;124(11):1683-1693.
- Calderón-Garcidueñas L, Rodríguez-Alcaraz A, Villarreal-Calderón A, Lyght O, Janszen D, Morgan KT. Nasal epithelium as a sentinel for airborne environmental pollution. Toxicol Sci. 1998;46(2):352-364.
- Calderón-Garcidueñas L, Solt AC, Henríquez-Roldán C, et al. Long-term air pollution exposure is associated with neuroinflammation, an altered innate immune response, disruption of the blood-brain barrier, ultrafine particulate deposition, and accumulation of amyloid beta-42 and alpha-synuclein in children and young adults. Toxicol Pathol. 2008;36(2):289-310.
- Ajmani GS, Suh HH, Wroblewski KE, Pinto JM. Smoking and olfactory dysfunction: A systematic literature review and meta-analysis. Laryngoscope. 2017;127(8):1753-1761.
- Lafreniere D, Mann N. Anosmia: loss of smell in the elderly. Otolaryngol Clin North Am. 2009;42(1):123-131.
- Schäfer L, Schriever VA, Croy I. Human olfactory dysfunction: causes and consequences. Cell Tissue Res. 2021;383(1):569-579.
- Nordin S, Monsch AU, Murphy C. Unawareness of smell loss in normal aging and Alzheimer’s disease: discrepancy between self-reported and diagnosed smell sensitivity. J Gerontol B Psychol Sci Soc Sci. 1995;50(4):P187-192.
- Nolan LS. Age-related hearing loss: Why we need to think about sex as a biological variable. J Neurosci Res. 2020;98(9):1705-1720.
- Mao Z, Zhao L, Pu L, Wang M, Zhang Q, He DZZ. How well can centenarians hear? Vinciguerra M, ed. PLoS ONE. 2013;8(6):e65565.
- Committee on Accessible and Affordable Hearing Health Care for Adults, Board on Health Sciences Policy, Health and Medicine Division, National Academies of Sciences, Engineering, and Medicine. Hearing Health Care for Adults: Priorities for Improving Access and Affordability. (Blazer DG, Domnitz S, Liverman CT, eds.). National Academies Press (US); 2016.
Motion graphics by Avo Media
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Based on a study of nearly 2,000 people, our sense of smell declines as we age, similar to our loss in vision and hearing. About a quarter of Americans over the age of 50 suffer from olfactory dysfunction—a difficulty identifying odors—which climbs to more than half of individuals between the ages of 65 to 80 years of age, and about 80 percent in those over the age of 80. And, that was before COVID-19, which affected the smell of nearly 50 percent of sufferers. Typically it was temporary, but as many as 15 percent of non-hospitalized COVID survivors were still experiencing problems with the ability to smell three or months later––and there are cases of it lasting for years.
As anyone with even a simple head cold can tell you, when you lose your sense of smell, you lose much of your sense of taste as well. Between 75 to 95 percent of what we think of as taste may actually be smell. This was all too vividly illustrated by the case of Algerian War soldiers whose tongues had been cut out remarkably reporting little loss of food and drink flavor sensation.
But hey, if loss of smell leads to loss of taste, think of all the weight loss! That was apparently the thought behind the development of a “novel nasal device,” gag-inducing silicone tubes you stick in your nostrils to cordon off your smell receptors. Researchers recorded a drop in preferences for sugary foods and beverages along with weight loss, but only among younger adults––presumably because the sense of smell of the older adults was already impaired. Making everything taste bland may help you skip a few doughnuts, but the flip side is that people with smelling difficulties tend to add more salt.
Older individuals were found to require two to three times more salt than those who were younger to achieve the same salty taste. It’s no wonder that the lifetime risk of developing high blood pressure may exceed 90 percent.
What can we do to preserve our sense of smell? Ambient air pollution is associated with olfactory dysfunction––thought to explain why nasal biopsies from residents of Mexico City, living and dead, showed more lesions and inflammatory changes than those living in low-pollution cities. We may not have a choice where we live, but there is definitely a direct source of air pollution tied to loss of smell we can all choose to avoid: cigarette smoke.
Smell loss can have serious consequences, for instance, missing a gas leak, smoke, or spoiled food. (If you have lost your sense a smell and use natural gas, please consider buying a gas detector). But, in terms of direct disability, most people who are affected don’t even to seem to be aware their smell is impaired, even when asked directly. Nearly eight out of 10 elderly individuals with smell loss thought they had normal smell sensitivity.
Hearing loss, however, is considered a major cause of global disability, ranking among the top chronic conditions affecting older adults. For far too long, though, as a National Academy of Medicine report put it, hearing loss has been “relegated to the sidelines of health care.” For those interested, check out my video series that starts with Age-Related Hearing Loss Is Not Inevitable, then a supplement shown to help, and ending with a video on dietary changes that can help, too.
Please consider volunteering to help out on the site.
- Doty RL, Shaman P, Applebaum SL, Giberson R, Siksorski L, Rosenberg L. Smell identification ability: changes with age. Science. 1984;226(4681):1441-1443.
- Desiato VM, Levy DA, Byun YJ, Nguyen SA, Soler ZM, Schlosser RJ. The prevalence of olfactory dysfunction in the general population: a systematic review and meta-analysis. Am J Rhinol Allergy. 2021;35(2):195-205.
- Saniasiaya J, Islam MA, Abdullah B. Prevalence of olfactory dysfunction in coronavirus disease 2019 (COVID-19): a meta-analysis of 27,492 patients. Laryngoscope. 2021;131(4):865-878.
- O’Byrne L, Webster KE, MacKeith S, Philpott C, Hopkins C, Burton MJ. Interventions for the treatment of persistent post-COVID-19 olfactory dysfunction. Cochrane Database Syst Rev. 2021;7(7):CD013876.
- Fernández-de-Las-Peñas C, Palacios-Ceña D, Gómez-Mayordomo V, et al. Prevalence of post-COVID-19 symptoms in hospitalized and non-hospitalized COVID-19 survivors: A systematic review and meta-analysis. Eur J Intern Med. 2021;92:55-70.
- Deng YK, Shi KT, Liu Z, Zeng M. Persistent olfactory dysfunction 2 years after onset of COVID-19. J Infect. 2023;86(2):154-225.
- Spence C. Just how much of what we taste derives from the sense of smell? Flavour. 2015;4(1):30.
- Spence C, Youssef J. Aging and the (Chemical) senses: implications for food behaviour amongst elderly consumers. Foods. 2021;10(1):168.
- Dicker D, Beck A, Markel A, et al. Weight loss, dietary preferences, and reduction in the sense of smell with the use of a novel nasal device. Obes Facts. 2020;13(5):473-486.
- Stevens JC, Cain WS, Demarque A, Ruthruff AM. On the discrimination of missing ingredients: aging and salt flavor. Appetite. 1991;16(2):129-140.
- Vasan RS, Beiser A, Seshadri S, et al. Residual lifetime risk for developing hypertension in middle-aged women and men: The Framingham Heart Study. JAMA. 2002;287(8):1003-1010.
- Ajmani GS, Suh HH, Pinto JM. Effects of ambient air pollution exposure on olfaction: a review. Environ Health Perspect. 2016;124(11):1683-1693.
- Calderón-Garcidueñas L, Rodríguez-Alcaraz A, Villarreal-Calderón A, Lyght O, Janszen D, Morgan KT. Nasal epithelium as a sentinel for airborne environmental pollution. Toxicol Sci. 1998;46(2):352-364.
- Calderón-Garcidueñas L, Solt AC, Henríquez-Roldán C, et al. Long-term air pollution exposure is associated with neuroinflammation, an altered innate immune response, disruption of the blood-brain barrier, ultrafine particulate deposition, and accumulation of amyloid beta-42 and alpha-synuclein in children and young adults. Toxicol Pathol. 2008;36(2):289-310.
- Ajmani GS, Suh HH, Wroblewski KE, Pinto JM. Smoking and olfactory dysfunction: A systematic literature review and meta-analysis. Laryngoscope. 2017;127(8):1753-1761.
- Lafreniere D, Mann N. Anosmia: loss of smell in the elderly. Otolaryngol Clin North Am. 2009;42(1):123-131.
- Schäfer L, Schriever VA, Croy I. Human olfactory dysfunction: causes and consequences. Cell Tissue Res. 2021;383(1):569-579.
- Nordin S, Monsch AU, Murphy C. Unawareness of smell loss in normal aging and Alzheimer’s disease: discrepancy between self-reported and diagnosed smell sensitivity. J Gerontol B Psychol Sci Soc Sci. 1995;50(4):P187-192.
- Nolan LS. Age-related hearing loss: Why we need to think about sex as a biological variable. J Neurosci Res. 2020;98(9):1705-1720.
- Mao Z, Zhao L, Pu L, Wang M, Zhang Q, He DZZ. How well can centenarians hear? Vinciguerra M, ed. PLoS ONE. 2013;8(6):e65565.
- Committee on Accessible and Affordable Hearing Health Care for Adults, Board on Health Sciences Policy, Health and Medicine Division, National Academies of Sciences, Engineering, and Medicine. Hearing Health Care for Adults: Priorities for Improving Access and Affordability. (Blazer DG, Domnitz S, Liverman CT, eds.). National Academies Press (US); 2016.
Motion graphics by Avo Media
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How to Preserve Your Sense of Smell
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Content URLDoctor's Note
My book How Not to Age has an entire section dedicated to preserving functions as we age—from senses to skin to immune system and more. Pick up a copy from your local library or wherever you buy your books. (As always, the proceeds from my books are donated to charity.)
The hearing videos I mentioned are:
- Age-Related Hearing Loss Is Preventable, So What Causes It?
- The Supplement Shown to Slow Age-Related Hearing Loss
- The Diet Shown to Slow Age-Related Hearing Loss
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