Goes well with: Green tea catechins, Resveratrol, Curcumin, Piperine
Number of scientific references: 58
Level of Evidence: Level I What is this?
Note: Quercetin’s benefits in neuropathy have not been confirmed by human studies; yet it’s therapeutic potential as evidenced by pre-clinical studies is promising. It is beneficial for diabetic and alcohol induced neuropathy. Considering it can relieve neuropathic pain and protects nerve health, it can be a potential natural remedy for neuropathy.
Including antioxidants in your diet is an important as fine tuning the macronutrient content of your daily meals.
Before we learn about the benefits of antioxidant quercetin in neuropathy, let’s explore the role of oxidative stress in nerve health.
Oxidative stress is an imbalance between prooxidants and antioxidants present in the body. It marks a rise of various chemical species that cause oxidative damage and destroy cells.
A study published in PloS One, 2013 revealed that increased level of oxidative stress causes aging of the nervous system and adversely affects motor and sensory nerves leading to the development of peripheral neuropathy.
Cancer chemotherapy and high glucose levels in diabetes can create a state of increased oxidative stress that causes nerve damage. Dietary antioxidants serve as excellent therapeutic agents for counteracting this stress.
Quercetin is a flavonoid or antioxidant derived from plants. The name is derived from the oak tree species called Quercus. It is found in many foods such as apples, berries, grapes, shallots, capers, tomatoes, honey, etc.
Red onions have high concentrations of this especially in the outermost part of the onion as well as the part closest to the root. Organically grown tomatoes have 79% more quercetin than chemically grown fruits.
It’s structure makes it a powerful antioxidant that can protect the body from oxidative stress. It is mostly found in combination with sugar molecules, and together they are known as quercetin glycosides.
Quercetin’s antioxidant and neuroprotective properties help repair nerve health and benefit in peripheral neuropathy. It helps relieve symptoms of neuropathy by protecting from neurotoxins.
Today we will be examining the benefits of quercetin’s antioxidant nature for peripheral neuropathy.
7 Proven Benefits of Quercetin For Neuropathy
Here are a few research studies that have examined the benefits of quercetin of neuropathy.
1. It is a natural antioxidant that helps protect nerve health
Various factors could contribute to oxidative stress in neuropathy. Nutritional deficiencies, chemotherapy or high levels of blood sugar lower the level of antioxidants present in the body.
Table of Contents
- 1 7 Proven Benefits of Quercetin For Neuropathy
- 1.1 1. It is a natural antioxidant that helps protect nerve health
- 1.2 2. Quercetin benefits in diabetic neuropathy
- 1.3 3. It can help in alcohol-induced neuropathy
- 1.4 4.It can benefit in chemotherapy-induced neuropathy
- 1.5 5.Quercetin may regulate immune responses and benefit in autoimmune neuropathy
- 1.6 6.It is a neuroprotective agent
- 1.7 7.Quercetin can help in relieving neuropathic pain
- 2 Bioavailability of Quercetin: Can it affect neuropathy treatment?
- 3 Dosage of Quercetin For Neuropathy
- 4 Precautions with Quercetin Use
- 5 Conclusion
Quercetin is highly researched for its antioxidant property. Researchers from the University of Florida have found that its total antioxidant capacity is 3.5 times higher than that of curcumin, the bioactive present in turmeric.
Oxidative stress amplifies inflammation in the brain in case of neuropathy. It can disturb fat metabolism and affect cholesterol synthesis which in turn reduces the thickness of myelin sheath that covers the nerve.
These contribute to nerve tissue damage and inflammation.
Quercetin’s natural anti-inflammatory activity helps alleviate pain and reduce the oxidative imbalance.
Quick Gist: Quercetin provides a combination of antioxidant and anti-inflammatory properties that can help improve nerve health.
2. Quercetin benefits in diabetic neuropathy
High levels of blood sugar can create a state of oxidative stress in diabetes paving the way for complications like diabetic neuropathy.
Quercetin decreases the production of reactive oxygen species caused by oxidative stress, elevates the level of antioxidant enzymes and inhibits inflammation to resolve diabetic neuropathy.
It can even reverse adverse effects of high glucose such as inhibition of growth of nerve cells and aid in nerve regeneration.
It ameliorates neuropathic pain caused by sensitivity to changes in temperature.
Diabetic neuropathy could even spread to the nerves linked with the intestine and cause gastric symptoms like constipation, diarrhea and gastroparesis.
A study published in Journal of Diabetes Complications, 2005 reported that topical application of a quercetin containing product brought about symptomatic relief in diabetic neuropathy.
The formulation contained quercetin, ascorbyl palmitate, and vitamin D. It aimed to reduce oxidative stress. The patients were asked to apply the formulation on the foot that was affected three times daily for four weeks.
As expected, the application reduced numbness, jolting pain, irritation and improved quality of life.
Quick Gist: Quercetin holds great therapeutic potential for diabetic neuropathy. Its antioxidant and anti-diabetic properties can help treat this condition. Further research in humans is required to confirm these findings.
3. It can help in alcohol-induced neuropathy
Chronic alcohol consumption creates oxidative stress leading to the production of free radical species that cause nerve damage.
Raygude et al. conducted an animal study where they assessed the effect of quercetin in alcoholic neuropathy.
The antioxidant was found to reduce allodynia (pain response to a trigger that would normally not cause pain) and increased pain sensitivity.
It improved the conduction velocity of the nerve (indicative of the ability to process electric impulses). It reduced DNA damage, inflammatory parameters, and levels of prooxidant enzymes.
Quercetin proved to be an excellent antioxidant, and the results were better than vitamin E treatment.
In response to this, a Letter to The Editor was published for Immunopharmacology, 2012. This letter highlighted the all-round benefits of quercetin for alcoholism :
• Protects liver health
• Protects other organs from alcohol-induced damage
• Protects from alcohol-induced cognitive decline
• Ameliorates alcohol withdrawal symptoms
• Prevents alcohol-induced gastric ulcers
Quick Gist: Research suggests that quercetin can help reduce oxidative stress in alcoholism and alleviate alcohol-induced neuropathy. This antioxidant can have all round benefits in alcoholism.
4.It can benefit in chemotherapy-induced neuropathy
Neuropathy is one of the major dose-limiting toxicities of chemotherapy. Oxaliplatin is frequently used to treat colorectal cancer, and it contributes to neuropathy.
One of the mechanisms involved in chemotherapy-induced neuropathy is the accumulation of the compound in nerve cell bodies at the root of the spinal nerve. This leads to toxicity.
Similarly, it even regulates immune responses to ameliorate neuropathic pain caused by a chemotherapeutic agent, paclitaxel.
Quick Gist: Animal studies suggest that quercetin strengthens antioxidant defences to inhibit chemotherapy-induced neuropathy. It also protects from potential neurotoxicity.
5.Quercetin may regulate immune responses and benefit in autoimmune neuropathy
The flavonol shows therapeutic action in some autoimmune conditions that could contribute to peripheral neuropathy such as multiple sclerosis, lupus, IBD, sarcoidosis etc. By alleviating symptoms of these autoimmune conditions, quercetin could help mitigate autoimmune neuropathy.
Quick Gist: Quercetin’s ability to regulate immune responses benefits in autoimmune condition and may help reduce the occurence of peripheral neuropathy in such conditions. Further research is required to confirm this action.
6.It is a neuroprotective agent
A study published in Oxidative Medicine and Longevity, 2016 highlights the possible mechanism behind quercetin’s neuroprotective action.
Researchers hypothesize that its antioxidant action helps strengthen cellular defenses against oxidative stress.
Additionally, it’s phytoestrogenic activity and ability to regulate sirtuin genes (these genes are actively researched upon with regards to longevity and aging) do contribute to quercetin’s ability to maintain the healthy nervous system.
These findings are limited to animal studies but are of great value concerning functional recovery in neuropathy.
Neurotoxicity is simply exposure to certain agents that are unhealthy for the brain and nervous system.
This could be exposed to environmental toxins or taking a high dose of certain medications (like chemotherapeutic agents) or exposure and accumulation of toxins present in processed items and foods.
Quick Gist: Quercetin by its antioxidant property helps protect the brain and nervous system. It helps in regeneration of nerve cells and recovery of damaged nerves. It even protects from neurotoxicity.
These findings are limited to preliminary studies and need to be validated by clinical trials in humans.
7.Quercetin can help in relieving neuropathic pain
Neuropathic pain is described as tingling sensations, pins and needles feeling, burning sensation or like an electric shock. This feeling can be very debilitating and disturb sleep.
Various studies in humans have found that quercetin can serve as a natural analgesic in painful conditions like arthritis. Some animal studies suggest that it can even help with pain occurring from nerve damage.
It can relieve neuropathic pain occurring in diabetic neuropathy by alleviating inflammation and supporting our endogenous opioid system (we produce opioid in our body for pain relief, and they also regulate our behaviour).
Civi et al. have found quercetin to be more effective than gabapentin (conventional medicine prescribed for neuropathic pain) and morphine (opioid painkiller) in relieving nerve pain in a model of nerve constriction injury.
Quick Gist: Quercetin can effectively reduce neuropathic pain. It regulates various neurotransmitter levels to help alleviate nerve pain.
Bioavailability of Quercetin: Can it affect neuropathy treatment?
As I previously mentioned quercetin has low bioavailability.Here is a bit of evidence based analysis on the current research on this topic.
Quercetin supplementation may not lead to increased availability of the antioxidant in the body
Despite its phenomenal antioxidant activity in lab settings, various studies have found that supplementation with the flavonol increases plasma quercetin levels but does not impact antioxidant status in healthy individuals.
Direct ingestion of dietary sources of the flavonol like onion, improve its bioavailability and reduce its elimination. It is converted to metabolites that are distributed to various organs leading to a therapeutic effect.
This can be awesome when it comes to improving antioxidant defences but when it comes to therapeutic effect in neuropathy, it may be difficult to get high dose quercetin from these sources.
In plants quercetin is found attached to a sugar molecule known as a glycoside. There are many types of quercetin-glycosides but the ones that show promising absorption are quercetin-3-glucoside and quercetin-4’-glucoside.
Dietary quercetin is better absorbed than supplements
Some studies show that consumption of dietary sources of this antioxidant improves its absorption.
Consumption of onion powder results in better absorption of quercetin than that of apple peel powder.
A study published The European Journal of Nutrition, 2017 reveals that quercetin derived from onion peel extract is more bioavailable than quercetin dihydrate capsules.
In fact, a study in humans shows that consumption of onion peel powder as a part of a meal shows better absorption of quercetin than onion peel or bulb extract.
Shi et al. conducted an interesting study where individuals were given either fresh onion soup (made from 100g red onion) or quercetin supplement tablet.
They observed that urinary excretion of quercetin after soup consumption was similar to that observed after taking a supplement. They found that 166mg of quercetin supplement is equal to 10mg quercetin aglycone equivalents from onions.
Combining quercetin with other natural antioxidants may help improve its absorption and effectiveness
Another really interesting point is combining the flavonol with other natural antioxidants.
Quick Gist: Quercetin is best absorbed from the food matrix like from onions or apples. Onion peel powder is one of the best sources of this antioxidant.
Quercetin glycosides are absorbed better than quercetin dihydrate. These supplements may not improve antioxidant status but still deliver a therapeutic effect.
Quercetin can be taken with other antioxidants, fats, and black pepper to increase its absorption.
Dosage of Quercetin For Neuropathy
The dosage of quercetin varies depending on the form of the supplement as well as the health condition.
Depending on the severity of symptoms, a dose of 500-1000mg of quercetin can help in neuropathy. Start with smallest dose available (250 or 500mg) and scale up gradually over weeks. Doses higher than 1000mg are not recommended. Cycling the dose or taking a break from quercetin intermittently is advised.
If opting for onion peel extract powder, the dose ranges from 150-200mg per day.
Quercetin supplements can be taken with other flavonoids such as curcumin, resveratrol or green tea catechins to get the benefits at a reduced dose.
I would highly recommend consumption of dietary sources of quercetin especially onion powder.
Here is a good resource for making onion powder at home. You can take this powder with a little black pepper for better absorption.
Proprietary quercetin powder can be included in juices or meals rich in dietary fats for better absorption. If taking supplements, it is best to take them after meals.
It is recommended to take quercetin for not more than three months at a stretch; when taking a break from supplements make sure you consume onion soup or powder or another dietary source of quercetin.
Please consult a health practitioner before taking quercetin supplements.
Precautions with Quercetin Use
Dietary consumption of quercetin does not have any side effects. High doses may cause side effects such as stomach upset, headache and nausea.
Doses higher than 1g may cause kidney toxicity. It is advisable to take periodic breaks when taking quercetin supplements.
It may interact with certain medications: antibiotics, felodipine, quinolones, cisplatin, doxorubicin, digoxin, cyclosporine, corticosteroids and blood thinners.
It’s supplementation safety is not assessed in pregnancy and lactation. Please consult a health practitioner before taking quercetin supplements.
Quercetin as an antioxidant helps protect nerve health. Experimental studies show that it can help in nerve regeneration.
The pharmacological properties of the antioxidant are beneficial for peripheral neuropathy treatment. It is highly recommendable for diabetic neuropathy because it is a natural anti-diabetic agent as well.
Human studies are required to confirm the benefits of quercetin in neuropathy. Yet, it seems like a very promising natural remedy for neuropathy.
In addition to taking supplements, it would be great to add onion peel powder to your diet for relief from neuropathic pain and for strengthening antioxidant defenses.
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