Can loss of sense of smell predict disease? Study links loss of sense of smell to 139 health conditions

Can olfactory training prevent forgetfulness? A new study shows that olfactory enhancement is effective.

study: Inflammation and loss of smell are linked to at least 139 medical conditions. Image credit: fizkes/Shutterstock.com

In a recently published review article, Frontiers of molecular scienceresearchers discussed the link between genetic, physical, and neurological conditions and olfactory loss and inflammation.

They believe that inflammation, the environment, and neuroanatomy can link anosmia to several symptoms, and that stimulating the sense of smell may help treat these health problems by reducing inflammation in the brain and body. We concluded that it may be useful for prevention.

Health conditions and loss of sense of smell

Anosmia is associated with 139 medical conditions, including hereditary or hereditary, physical, and neurological conditions. Extensive research supports links to conditions such as rhinitis, depression, Parkinson's disease, Alzheimer's disease, and coronavirus disease 2019 (COVID-19).

In many cases, anosmia may appear before symptoms appear. This indicates that loss of smell may predict future cognitive decline and even mortality.

The sense of smell is correlated with cognitive abilities such as decision-making, verbal fluency, and memory. They are also strong indicators of mortality and are better predictors than heart disease.

There are gender differences, with men's olfactory thresholds strongly correlated with executive function and language, whereas in women, olfactory discrimination is associated with visuospatial abilities.

Causal mechanisms and underlying processes

The olfactory system can be affected by conditions that affect both the brain and body. Neurological and physical symptoms can have a negative impact on the olfactory system, and anosmia can increase the risk of developing several diseases. Anosmia is often associated with inflammation and is seen in genetic and neurological disorders.

Inflammation can damage the olfactory system through inhaled substances (such as odors and pollutants) and blood.

Smell problems related to respiratory inflammation are seen in conditions like Parkinson's disease, and the loss of smell in COVID-19 patients is also thought to be caused by inflammation. However, some diseases, such as Kallmann syndrome, cause loss of smell without inflammation.

Treatment response for patients with COVID-19 is variable, with nasal steroids effectively reducing inflammation in young adults. Olfactory training shows age dependence efficacyEspecially for young people with anosmia. Certain scents (ginger, lavender, and eucalyptus) have anti-inflammatory properties in animal studies, suggesting a potential therapeutic role.

Diet may also be a risk factor, with diets high in healthy fats being associated with increased risk of cognitive function and loss of sense of smell. In mice, omega-3 supplementation prevented memory and smell loss.

Loss of smell is associated with memory decline, particularly in dementia, due to a direct brain pathway between the olfactory and memory centers.

Brain areas involved in memory (amygdala and hippocampus) deteriorate with loss of smell. Factors such as infections, stress, pollution, and smoking can impair both your sense of smell and memory.

Longitudinal study shows COVID-19-related anosmia predicts damage to memory-related brain regions, and COVID-19 is associated with cognitive decline and increased risk of Alzheimer's disease It shows.

Benefits of enriching your sense of smell

Olfactory enhancement, the process of stimulating the sense of smell, improves cognitive symptoms. Exposure to essential oils improves brain health by balancing neurotransmitters, reducing oxidative stress and inflammation, and enhancing cognition, memory, and neuroprotection.

In healthy adults, especially older adults, daily exposure to essential oils over several months can also benefit memory in older adults, as olfactory stimulation improves memory. Minimal nighttime olfactory enrichment (2 hours each night for 6 months) significantly improved memory scores in older adults.

Studies have shown that frequent exposure to smells improves memory, depression, attention, and language skills in people with dementia. A rich olfactory environment combined with education and social activities may promote cognitive reserve and protect against symptoms of dementia, even in the presence of dementia itself.

The researchers hypothesize that these benefits may be due to three mechanisms.

First, olfactory dysfunction and cognitive decline are associated with inflammation, and pleasant scents may reduce inflammation and aid memory and cognitive symptoms in neurological conditions.

Second, daily exposure to smells increases the olfactory processing areas of the brain, which may improve memory and cognitive function. The third may be due to electrical stimulation. Stimulating the olfactory bulb has been shown to reduce beta-amyloid plaques (associated with Alzheimer's disease) and potentially improve working memory in animal models.

conclusion

Anosmia is associated with at least 139 medical conditions. Anosmia loss often precedes the onset of symptoms of medical conditions, suggesting that it may increase vulnerability to these conditions and may predict poorer memory and increased risk of death.

Inflammation may play an important role in linking olfactory dysfunction to memory impairment and other medical symptoms, but environmental and neuroanatomical influences also contribute, and a bidirectional relationship may form. There is a possibility that

Enhanced sense of smell can enhance memory in both healthy adults and adults with dementia, likely due to its anti-inflammatory effects. Pleasant scents may reduce inflammation and reduce symptoms of various medical conditions.