Dr. Vliet’s Health Tip: Taste Bud Bootcamp: Comeback After COVID to Revive Taste and Smell

I have been treating patients with the widespread damage from COVID-19 and the COVID shots since the beginning of the pandemic and subsequent “vaccine” rollout. I have frequently seen patients who lost their sense of taste (ageusia) and smell (anosmia), and it didn’t return after recovery from the respiratory phase of the illness. For many of my patients who got the COVID shots, especially those getting boosters, the spike protein and LNP inflammatory damage causing impaired taste and smell has lasted much longer and has typically been more severe.

COVID Loss of Sense of Taste and Smell: the Big Picture
COVID-19, and the COVID shots, have been widely reported to cause many types of neurologic damage and dysfunction. Anosmia, stroke, paralysis, cranial nerve deficits, encephalopathy, delirium meningitis, seizures, cognitive damage, and full-blown dementia are some of the complications in patients with COVID-19 and after the COVID shots.

Let’s look at the pathways involved in normal sense of taste and smell to help us better understand the mechanisms of damage I discuss below: The sense of smell originates from olfactory neurons in the olfactory epithelium in the upper part of the nasal cavity. It travels via bundles of the olfactory nerves to the olfactory bulb and then along the olfactory tract to the septum, cerebral cortex and other parts of the brain. Damage to either the olfactory neurons or their supporting cells and/or the olfactory bulb could lead to anosmia, or loss of smell. Recent MRI studies have shown transient changes in the olfactory bulb that accompany COVID-19-related anosmia, consistent with CNS involvement in some of the patients.

The lipid nanoparticles (LNP) in the COVID injections and boosters are a separate and prolonged source of damage to these nerve pathways, blood vessels, epithelial and endothelial cells. For example, a study of the intracerebral distribution of gold nanoparticles after inhalation exposure in rats shows that the nanoparticles are found in nuclei connected to the olfactory and limbic systems, including the olfactory bulb, hippocampus, frontal cortex, striatum, entorhinal cortex and septum. This can explain both the damage to taste and smell, as well as mood and sleep regulation in the limbic system. This study also could be an indication of the potential areas of spread of viruses from the olfactory bulb. The SARS-CoV virus, which is taxonomically very similar to SARS-CoV-2, is able to enter the brain via the olfactory bulb, and infection results in rapid, transneuronal spread to connected areas of the brain. CNS infection is thought to be the main cause of death in mice experimentally infected with the SARS-CoV virus since intracranial inoculation with low doses of this virus results in death, even though there may not be much infection detected in the lungs.

Besides the olfactory axonal route, SARS-CoV-2 may pass from non-neuronal olfactory epithelium cells directly to the cerebrospinal fluid surrounding olfactory nerve bundles and enter the brain. Other viruses, e.g. herpesvirus-6 or rabies virus, are also known to hijack existing vesicular axonal transport machineries to travel within the brain.

Taste is also often affected by COVID-19. Our sense of taste is conveyed via axons in the facial, glossopharyngeal and vagus nerves that terminate in the nucleus of the tractus solitarius in the medulla oblongata. The loss of taste strongly suggests damage to this nucleus, possibly via backward transport of the virus, or the LNP and spike protein in the shots.

Consistent with my own medical practice experience, case series and systematic reviews make it clear that alterations in and/or loss of sense of smell and taste CAN and DO occur after COVID-19 “vaccine” shots and boosters.  Although these problems usually resolve over time without treatment, there are many patients for whom these symptoms persist for extended periods of time and significantly impair quality of life. Five studies consisting of 11 patients were included in systematic review I cited above in the link. Of the 11 patients, 5 patients had received the Pfizer COVID-19 vaccine and 6 patients received the Oxford-AstraZeneca COVID-19 vaccine, of which 6 patients developed symptoms after the first dose of vaccination and 5 patients were symptomatic after the second vaccine dose. Most of the patients developed symptoms within 1 week after the vaccination. The disorders of the patients included partial or total anosmia, parosmia, phantosmia, hyposmia, ageusia, and dysgeusia. The patients had additional symptoms besides smell or taste disorders: these included arthralgia, fever, chills, rhinorrhea, myalgia, abdominal pain, fatigue, muscle weakness, altered bowel pattern, aural fullness, tinnitus, and headache.

COVID Loss of Sense of Taste and Smell: Specific Mechanisms of Damage
COVID-19-related loss of smell and taste involves a multifactorial mechanism of viral infection of olfactory support cells expressing ACE2, followed by immune-mediated inflammation that disrupts sensory neuron function and olfactory signal transduction. Secondary neuroinflammatory effects and structural brain changes may underlie persistent and longer-term symptoms, especially in those who got the COVID injections and boosters, since those people having ongoing spike protein and LNP toxicity causing damage and impaired recovery.

The mechanisms of damage related to COVID-19 loss of smell and taste primarily involve infection and dysfunction of the olfactory epithelium’s support cells rather than direct infection of olfactory neurons, along with inflammation and altered gene expression affecting the olfactory pathway.

1. Infection of Support Cells in the Olfactory Epithelium
   • SARS-CoV-2 infects support cells and Bowman’s gland cells in the olfactory epithelium, which express the ACE2 receptor that the virus uses to enter cells. This infection leads to disruption of the epithelium’s integrity and function, secondarily impairing olfactory sensory neurons that do not get infected directly.
   • Damage to these support cells causes loss of the cilia (hair-like projections) and loss of olfactory receptor neuron function, leading to acute loss of smell (anosmia).
2. Immune-Mediated Inflammation
   • COVID-19 illness and the spike protein/LNPs in the COVID shot trigger local inflammation and release of pro-inflammatory cytokines (e.g., TNF-α, IL-6) that can impede regeneration of olfactory neurons and reduce the lifespan of taste bud cells, contributing to prolonged sensory loss for both taste and smell.
   • The immune response downregulates olfactory receptor gene expression, altering signal transduction in sensory neurons.
3. Neuroepithelial and Central Nervous System Effects
   • Direct viral invasion of olfactory neurons and the brain is unlikely, but neural pathways may be indirectly affected by inflammation and altered connectivity in olfactory networks, correlating with persistent anosmia and associated neuropsychological symptoms such as mood and memory changes in long COVID, and in vaccine-injured patients.
   • Structural brain changes, such as cortical thinning and white matter alterations, have been observed in patients with persistent anosmia, indicating central nervous system involvement beyond the peripheral olfactory system.
4. Role of the Renin-Angiotensin System (RAS)
   • SARS-CoV-2 interaction with ACE2 downregulates this receptor causing dysregulation of the RAS, increasing pro-inflammatory angiotensin II levels, which may exacerbate local inflammation and tissue damage in the olfactory system.
5. Timing and Recovery
   • The rapid onset and often rapid recovery of anosmia in many people suggest the primary damage is to support cells and the olfactory epithelium rather than loss of olfactory neurons, which require longer regeneration times. In prolonged cases, such as after the COVID injections, persistent inflammation and central nervous system changes may contribute to the continuing damage to these pathways.

Treatment Strategies:  I recommend a stepwise approach for treating loss of smell (anosmia) and taste (ageusia) from COVID-19 illness and COVID shots

Many of the patients I treated for COVID illness eventually regained their loss taste and smell after fully recovering from the respiratory illness – although I found that taste and smell recovery typically took longer to come back than other symptoms took to resolve. Many of my patients did not need further therapy beyond the multi-pronged approach I used to treat the respiratory illness and correct any nutritional deficiencies, such as zinc and the B complex of vitamins involved in optimal nerve function.

This is my stepwise approach:

1. Non-invasive therapies
2. Correcting nutritional deficiencies
3. Consider anti-inflammatory pharmacological Rx options
4. Other interventions as needed for specific patients

1. Non-invasive, first-Line measures

• As I said above, many patients with COVID-19-related loss of smell and taste recover spontaneously within 1-4 weeks, and they don’t need additional treatment. I emphasis supportive and comfort care such as oral and nasal flushes and rinses with saline solution with a small amount of added povidone iodine.  It is important to stay hydrated during recovery and continue vitamins and minerals that support nerve function.
• For persistent symptoms (longer than 3-4 weeks),  I recommend “olfactory training” that involves deliberate, repeated exposure to a set of standardized scents (rose, lemon, clove, eucalyptus) to stimulate recovery.

1. Correction of Nutritional Deficiencies

Zinc is an essential mineral which catalytic, structural, and regulatory functions in the body. Zinc ultimately supports immune and neurological function, growth, taste acuity, nutrient metabolism, reproductive health and supports healthy aging.  I recommend having a serum zinc blood test at least on an annual basis, more often if there is a deficiency to monitor for replacement. Blood zinc levels are typically considered to be “normal” between 60-120 mcg/dL, but for optimal zinc to maintain critical functions, I recommend level of 90-110 mcg/dL.

I have been shocked at how many supposedly healthy patients, most taking a multivitamin, are actually deficient in zinc!  But this may mot be so surprising when we look at the global data: Low zinc affects at least 2 billion people worldwide, and many more people likely have undetected zinc deficiency. Individuals especially at risk of zinc deficiency are these groups:

• children
• pregnant and breastfeeding women
• high fiber, plant-based diets
• older adults – which contributes to accelerated aging in our bodies
• those on proton pump inhibitors and other “acid reducer” medicines

Zinc is required for enzymes central to olfactory and gustatory function, and its deficiency may worsen or prolong olfactory dysfunction from infections, including COVID-19. Symptoms of anosmia/ageusia reported in COVID-19 may reflect an adaptive response of locally decreased nasopharyngeal zinc (Zinc).

Older literature has demonstrated associations between viral infection and altered taste/smell, and between these variables and Zinc deficiency. In a sample of 35 individuals reporting taste/smell dysfunction, 51% reported it occurred immediately prior to/concurrent with, respiratory illness. Zinc was shown to reduce the symptoms, but the administration protocol was not described. In a group of 103 people with altered taste/smell, 57% reported abrupt onset “during or soon after a respiratory illness”, with three-days or more of fever also demonstrating association. Zinc levels were decreased in those with taste/smell disruption, and Zinc (zinc sulfate) supplementation mitigated the symptoms in a single-blind study. Interestingly, the duration of altered taste/smell in these earlier participants ranged from 7 months to 49 years with a mean of 3.5 years. A simple blood test for zinc levels and appropriate supplementation could be a much quicker solution!

Zinc serves important roles in more than 300 important roles in the body, and more than 300 enzymes depend on zinc for their normal activities in cellular metabolism. Zinc is important for healthy vision, healthy growth, and sports recovery. Zinc is also required for strenuous exercise, and while exercise can deplete zinc stores, low zinc levels in the muscles can reduce muscle endurance. Zinc also plays a crucial role in bone health by supporting bone remodeling and inhibiting bone resorption. Zinc is essential for osteoblast activity, stimulates bone growth and fracture healing, and helps maintain bone mineral density (and stave off osteoporosis!)

But the one thing Zinc is most known for is its role in healthy immune system function. Zinc affects virtually all aspects of our immune system, from the nonspecific barrier functions of the passive immune system (skin, mucous membranes, etc.), to the specific lymphocytic functions of the active immune system. Zinc is needed for the development of neutrophils (a type of white blood cell) and other natural killer cells in the nonspecific immune defense and offers vital support for other specific immune defenses. Zinc as a supplement has been recommended for early treatment of viral illnesses, the flu and the common cold. Research is finally catching up to what I and many of my colleagues have known throughout the pandemic is the role zinc supplementation can play in treating COVID-19 related symptoms, virus replication, and COVID-19 related inflammation and neurological damage.

Speaking of inflammation, zinc plays a crucial role in brain inflammation, impacting both neuroprotective and neurotoxic effects. Zinc’s role is complex:  both deficiency and excessive accumulation are potentially neuroinflammatory. Zinc helps protect brain cells from damage caused by oxidative stress and inflammation by acting as an antioxidant. It also can inhibit the expression of proinflammatory factors like IL-1B, TNF-a, and IL-6.

On the other hand, excessive zinc accumulation can lead to neuronal death and exacerbate cerebral ischemia/reperfusion injury. Therefore, maintaining balanced zinc levels is crucial for preventing neuroinflammation and neurodegenerative diseases such as Alzheimer’s.

Our endocrine system also relies heavily on adequate zinc status. Zinc is required for sperm maturation and fetal development. Zinc is necessary to assist in the regulation of insulin activity and for the conversion of thyroxin (T4) to the active thyroid hormone triiodothyronine (T3).

Skin and mucous membranes depend on zinc for their maintenance and integrity. Skin is in a continual state of renewal, placing a high demand on zinc-based enzymes and proteins that direct this process. The importance of zinc physiologically is especially evident in studies of wound healing and inflammation reduction. Zinc and vitamin A (also important in wound healing) have a fundamental relationship as zinc is required for synthesis of retinol-binding protein—the protein that transports vitamin A in the blood.

Zinc is also essential to the production of an enzyme that converts vitamin A to one of its active forms, and this helps support vitamin A’s vital role in night vision and one way zinc supports healthy vision in general, especially as we age. Zinc’s role in sensory perception extends not only to vision but also to normal taste and smell acuity.

As you can see, our bodies requirements for zinc are widespread and immense, with a constant demand for adequate supply of zinc. But most people don’t realize that our body has no specialized system for storing zinc. We much take in adequate daily intake of zinc for these critical functions—either with our diet or with supplements.

But keep in mind that phytates, oxalates, and fiber in foods can bind to zinc (and other important minerals) and make the bioavailability of dietary zinc compromised in many food sources and common zinc supplements. Other minerals, including iron, calcium, and copper, can interfere with zinc absorption and challenge attainment of adequate zinc levels. To overcome these challenges, I recommend several strategies:

1. Take zinc on an empty stomach, either ½ hour before a meal or 2 hours after.
2. Do not take with other minerals. Calcium, Iron, Magnesium, Copper can compete with zinc for absorption in the gastrointestinal tract.
3. Do not count on full absorption from multimineral and vitamin supplements.  If your zinc levels are low, you should take a separate zinc supplement.
4. Do not take a zinc supplement combined with herbal ingredients as these can block absorption.
5. Be careful taking zinc with certain medications that can bind with zinc and reduce the absorption and effectiveness. These medications include antibiotics such as tetracycline and fluoroquinolones (e.g., ciprofloxacin), chelating agents such as Penicillamine, and gastroprotective medications that reduce stomach acid such as proton pump inhibitors (omeprazole, pantoprazole). An acid environment is necessary for optimal uptake. It is advised to separate the dosing schedules—usually by a couple of hours—for zinc and these medications.
6. Chose a chelated zinc supplement for enhanced absorption and bioavailability. Mineral chelates are less likely to bind to antinutrients which can reduce their absorption and have demonstrated higher bioavailability in research studies.

Since zinc is the most recognized nutrient deficiency linked to COVID-19 loss of taste and smell, I recommend our TruZinc™ to support my patients recovering from loss of taste and smell as well as other symptoms of low zinc discussed in detail in my earlier Health Tip. Zinc is a critical part of an important resilience building supplement regimen.

TruZinc™ is a fully reacted, proprietary TRAACS® amino acid chelate formulated for enhanced absorption created by the pioneer of zinc chelated minerals and the globally trusted Albion® Minerals brand for my TruZinc™ supplement.  TruZinc™ bisglycinate chelate is a fully reacted chelated mineral that is absorbed intact and breaks apart in the intestinal cell for transport. It is a low ph, highly stable structure that is easily absorbed.

Chelation acts like a “claw” wrapping around the mineral, this chelate forms a robust bond with ligand molecules to create a high-potency source of zinc formulated for enhanced absorption. This chelation occurs by coupling zinc with two glycine molecules to facilitate its absorption across the intestinal wall and reduce interference from phytates and competing minerals. You get the quantity of elemental zinc as stated on the label but with better absorption and bioavailability.

Even more impressive is that in a study comparing the oral bioavailability of zinc bisglycinate chelate to common inorganic zinc gluconate, TruZinc™  in chelated form increased absorption by more than 43%. So, you are getting more benefit per dose with our TFH formulation.

Other Micronutrients

• Vitamin B12 deficiency, and deficiencies of other B vitamins, has also been associated with disruption of taste and smell. It affects epithelial cells in the tongue, leading to tongue pain and altered taste perception. COVID-19 patients with higher vitamin B12 levels report better olfactory function than those deficient.
• Deficiencies in other micronutrients, such as copper and magnesium, are less directly established but can influence overall neurological health and sensory function. Low copper affects the nervous system and can cause neurological abnormalities that might manifest as deficits in smell or taste, though most literature emphasizes anemia and more prominent neurological features. Magnesium’s role is more indirect, but low magnesium levels have been associated with olfactory decline in older adults through its involvement in cognitive health and oxidative stress pathways. In addition, COVID-19-related inflammation and oxidative stress may deplete antioxidants and micronutrients, also potentially contributing to prolonged sensory loss.

Anti-viral and Anti-inflammatory Pharmacological Rx Options:

• Hydroxychloroquine: I use this older, safe medication frequently in the treatment of inflammatory conditions, and I have found it very helpful in treating the COVID-induced (illness or shots) loss of taste and/or smell.  I have found tht it works better than most corticosteroid options and has far fewer adverse side effects than “sterioids” do.

HCQ has several unique properties that distinguish it from other anti-inflammatory drugs:

1. it is lipophilic, which enhances its ability to cross the blood-brain barrier (BBB), so it has the potential to act not only in the periphery but also in the CNS, and it has been a useful addition to our limited armamentarium against COVID and the injuries from the COVID shots.
2. It is a non-selective inhibitor of phospholipase A₂ isoforms, including cytosolic phospholipase A₂ (cPLA₂), which is not only activated by cytokines but itself generates arachidonic acid that is metabolized by cyclooxygenase (COX) to pro-inflammatory eicosanoids. Free radicals are produced in this process, which can lead to oxidative damage to the CNS.

There are multiple ways that HCQ has been useful and successful for my patients with COVID-19 or COVID shot inflammatory and immune damage:

1. It inhibits PLA_2.
2. It is a basic molecules capable of affecting the pH of lysosomes and inhibiting the activity of lysosomal enzymes that add to inflammatory damage.
3. It appears to affect the expression and Fe²⁺/H⁺ symporter activity of iron transporters such as divalent metal transporter 1 (DMT1), hence reducing iron accumulation in tissues and iron-catalysed free radical formation.
4. It inhibits viral replication. The latter may be related to their effect on inhibition of PLA₂ isoforms. Inhibition of cPLA₂ impairs an early step of coronavirus replication in cell culture. In addition, a secretory PLA₂ (sPLA₂) isoform, PLA2G2D, has been shown to be essential for the lethality of SARS-CoV in mice. It is important to take note of what ongoing clinical trials on chloroquine and hydroxychloroquine can eventually tell us about the use of antimalarials and other anti-inflammatory agents, not only for the treatment of COVID-19, but also for neurovascular disorders such as stroke and vascular dementia.
5. It helps reduce inflammatory pain
6. It has beneficial effects on blood glucose, hemoglobin A1C and lipids (cholesterol, HDL, LDL, Triglycerides) which in turn reduces inflammatory damage.
7. It has many anti-cancer properties.

• Corticosteroids: This class of medicines may be administered orally, intranasally, topically, and IV. Intranasal corticosteroid sprays may also be helpful in patients with loss of smell more than 3-4 weeks if associated with nasal symptoms and congestion.  In my practice, I have had better results with HCQ orally, with fewer side effects, especially when compared to oral corticosteroids.

In summary,  I have always recommended zinc as part of my essential supplements list and why I have included it in not only my Resilience formula but also as a critical component of my Early Treatment COVID protocols and prevention regimen.  Since zinc is the most recognized nutrient deficiency linked to COVID-19 loss of taste and smell, I recommend our TruZinc™ to support my patients recovering from loss of taste and smell as well as other symptoms of low zinc discussed in detail in my earlier Health Tip. Zinc is a critical part of an important resilience building supplement regimen.   Click here to read my earlier health tip Dr. Vliet’s Health Tip:  Beyond COVID and the Common Cold: Zinc is Your Overlooked Powerhouse! for more on symptoms of low zinc, causes of zinc deficiency, and food sources of zinc.

CAUTION: As always, we urge you to avoid supplements without checking knowledgeable sources to evaluate your medical situation, proper lab tests to verify what is needed, and to make sure to avoid adverse interactions with prescription medicines and other supplements you take.

All Truth for Health Foundation Products Meet or Exceed cGMP Quality Standards, the highest quality standard for supplements sold in the USA. For more information, references from studies are listed in the Product Data Sheets for each product, available on our website.  Under medical practice regulations, we are unable to answer individual medical questions or make specific individual supplement recommendations for people who are not established patients of Dr. Vliet’s independent medical practice.

I encourage you to consider our other natural medicines with our top quality, cGMP-compliant professional formulas for TruImmune™Boost, TruNAC™, TruImmunoglobulin,™ TruC with BioFlav™ (Vitamin C with complete Bioflavonoids), Tru BioD3™, TruZinc™, TruMitochondrial ™Boost and TruProBiotic™ Daily to replenish critical bifidobacteria depleted by COVID shots, viral illnesses, and antibiotic therapy.

To Your good health and improving resilience!
Elizabeth Lee Vliet, MD
Preventive and Climacteric Medicine Physician
www.ViveLifeCenter.com

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