Loss of smell or reduced sense of smell is among early clues for the Parkinson’s Disease (PD) development in an individual. Not all, but 90% of Parkinson’s patients notice a reduced sense of smell at an early stage of the disease. Loss of sense of smell can often be overlooked by diagnosing physicians for being an early sign of Parkinson’s. The symptom may occur years before the onset of motor symptoms or a Parkinson’s diagnosis.

Without the sense of smell, food may taste different. At times, Parkinson’s fighters can find themselves in a dangerous situation, unknowingly. For instance, without the ability to detect odors, they would not be able to smell a gas leak, smoke from a fire or even sour milk.

What causes loss of smell in Parkinson’s disease?

Due to dopamine deficit, various parts of the nervous system and brain are affected, including the olfactory bulb, which is responsible for controlling the sense of smell in an individual. Few researchers argue that Parkinson’s may initially begin with bacteria, viruses or environmental toxins entering the brain through the nose. Once the olfactory bulb has been infected, a gradual spread throughout the brain will be triggered.

Several studies show that functional units of the olfactory bulb, known as its glomeruli, are reduced by more than half in Parkinson’s patients compared to those without the disease. Typically, the glomeruli component of the olfactory bulb should be about 70 percent of the structure, however, in Parkinson’s patients, it was found to be only 44 percent of it.

It is believed that olfactory deficit, which results in impaired smell in Parkinson’s, is independent of disease severity and duration. However, image studies hint that the degree of the symptom may be progressive in the early stage, just like any other Parkinson’s symptom.

Options to treat loss of smell in Parkinson’s disease

Early detection is a crucial step to understanding the causes of and developing better treatments for loss of smell in Parkinson’s. Even before the typical motor impairments occur in Parkinson’s, it may be possible to detect early changes in the brain. Unfortunately, the complete loss of smell is not always treatable. But, there are steps one can take to make living with the inability to smell safer.


Because loss of sense of smell along with other non-motor symptoms of constipation and sleep disorders, may precede the disease by several years, researchers are increasingly focused on discovering ways to stop Parkinson’s progression. Research indicates that Omega-3 rich food (wild-caught salmon, shrimp, walnuts, and flaxseed oil) may help build resistance to the toxin that causes Parkinson’s motor symptoms. Since psychological stress is a risk factor for the disease, stress management practices such as Yoga can help the practitioner prevent an individual onset of motor symptoms in Parkinson’s.


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