Quercetin For Dogs: Nature’s Benadryl

quercetin for dogs

When your dog suffers from allergies, you might consider giving an antihistamine drug like Benadryl.

But did you know there’s a natural allergy solution contained in many fruits and vegetables? It’s a powerful flavonoid called quercetin … and it has antihistamine effects.

Flavonoids are plant-based compounds with strong antioxidant properties. And quercetin is so effective in helping allergies that it’s known as “Nature’s Benadryl.” (But it doesn’t have the risks and side effects that come with that little pink pill that’s the pharmaceutical Benadryl).

Let’s take a closer look at quercetin for dogs, and how it works.

What Are Allergens?
An allergy is an abnormal response by your dog’s immune system. It happens when his body reacts to a usually harmless substance in the environment … called an allergen. The immune system identifies certain everyday substances as dangerous. Allergens can be inhaled, eaten or even absorbed through your dog’s skin.

As your dog’s body tries to get rid of the allergen, allergic reactions like skin, digestive, and respiratory issues can surface. Signs of these reactions include paw licking or chewing, ear infections, watery eyes, itchy skin, and a lot of scratching.

One of the best ways to address allergies is to remove the allergen. The less your dog is exposed to something his body doesn’t like, the less he’ll react to it. But more exposure to an allergen means a more intense and long-lasting allergic response.

Types Of Allergens
There are two types of allergies: food and environmental.

Common food allergens include wheat, soy and corn. These can cause itchiness, difficulty breathing or gastrointestinal issues like vomiting, diarrhea or gas).

Common environmental allergens are tree, grass and weed pollens, mold spores, dust, dust mites, cleaning products, insect bites and insect control products.

To minimize environmental allergens, keep things clean and use natural, non-chemical products and cleaners in your home and yard. You may need to limit the amount of time your dog spends outside when pollen counts are high.

Is It Yeast?
Sometimes, what looks like allergies could in fact be an abundance of yeast.

Too often, dogs are diagnosed with allergies when they are actually suffering from a systemic dog yeast infection. Yeast lives in the gut … which is also home to about 90% of your dog’s immune system. So it can cause symptoms that get confused for allergies.

When you’re trying to get to the bottom of your dog’s allergies, you’ll want to rule out yeast. Click on the link below for more information on how to do that.

RELATED: Find out how to identify and treat a dog yeast infection.

How Histamine Causes Allergic Reactions
During an allergy attack, the immune system produces antibodies to a specific allergen. These antibodies then cause certain cells in the body to release chemicals into the bloodstream. One of these chemicals is histamine.

It’s one of the biggest players in the allergic response, causing much of the inflammation, redness and irritation your dog experiences. Then, being exposed to the same allergen again will cause this same antibody response and allergic reaction.

Safety Note
Occasionally your dog’s response to an allergen and can be a serious, even life threatening response called anaphylaxis. This could be a response to a drug, vaccine, insect sting or other allergen. With anaphylaxis, all the symptoms of a “normal” allergic reaction are exaggerated. You could see rapid facial swelling, difficulty breathing, pale gums … and your dog may even lose consciousness. Anaphylaxis can be deadly, so get him to the vet immediately!

Quercetin Is A Natural Antihistamine

So let’s put together what we know.

Quercetin is a flavonoid with antioxidant, antihistamine and anti-inflammatory properties. During an allergic reaction the body releases histamine. Histamine leads to inflammation, redness and irritation.

Research has shown that quercetin can turn off histamine production and control inflammation. So it’s often known as Nature’s Benadryl.

Quercetin also helps manage cellular activity associated with inflammation … meaning less itching!

Quercetin also inhibits the production of specific inflammatory it’s also helpful in treating asthma and respiratory issues involving inflammation. Bronchial tubes in the lungs become restricted during an asthma attack (bronchoconstriction), and studies show that quercetin can help dilate the bronchial tubes.

BONUS: Quercetin Has Anti-Cancer Effects

Polyphenols in fruits and vegetables are important in cancer prevention. Several studies have shown that the anti-inflammatory effects of quercetin and flavonoids can limit cancer cell growth in many types of cancers.

Dr Demian Dressler, the well-known Dog Cancer Vet, explains that low dose chemotherapy treatment (metronomic chemotherapy) targets certain enzymes with anti-inflammatory drugs. This reduces blood flow to cancer cells, helping slow cancer growth. But quercetin can partially block the very same enzymes!

And Dr Dressler confirms research shows quercetin is safe.

Quercetin may also support bone health, weight reduction, heart health and overall performance. Studies have even shown evidence that quercetin may protect against the damage caused by bad cholesterol (LDL) and reduce blood pressure (hypertension).

How To Give Your Dog Quercetin

Quercetin can be found in many fruits and vegetables, especially dark berries, apples (especially the skin), citrus fruits, dark cherries and parsley. Add these foods to your dog’s regular meals up to about 10% of his diet.

Food sources of quercetin are best for absorbability. You can buy quercetin supplements at health food stores containing different types of quercetin. Some quercetin supplements are quercetin dihydrate, which is water-insoluble so may not be absorbed as well as other kinds. Supplements are often packaged with the enzyme bromelain, which is said to increase the bioavailability of quercetin.

If you buy a supplement made for people, assume the dosage is for a 150 lb human and adjust for your dog’s weight. Start with a low dose to make sure your dog doesn’t get any digestive upset.

Is quercetin safe for dogs?

Research shows that quercetin is safe for dogs. Some potential side effects seen in people include upset stomach and headaches. Check with your vet before using quercetin if your dog has kidney disease. Quercetin safety hasn’t been shown for pregnant or lactating females.

Jafarinia M, Sadat Hosseini M, et al. Quercetin with the potential effect on allergic diseases. Allergy Asthma Clin Immunol. 2020 May 14;16:36.14;16:36. 

Mlcek J, Jurikova T, Skrovankova S, Sochor J. Quercetin and Its Anti-Allergic Immune Response. Molecules. 2016 May 12;21(5):623.

Yang CC, Hung YL, et al. Quercetin inhibits histamine-induced calcium influx in human keratinocyte via histamine H4 receptors. Int Immunopharmacol. 2021 Jul;96:107620. 

Cesarone MR, Belcaro G, et al. Supplementary prevention and management of asthma with quercetin phytosome: a pilot registry. Minerva Med. 2019 Dec;110(6):524-529. 

Joskova M, Franova S, Sadlonova V. Acute bronchodilator effect of quercetin in experimental allergic asthma. Bratisl Lek Listy. 2011;112(1):9-12. 

Niedzwiecki A, Roomi MW, Kalinovsky T, Rath M. Anticancer Efficacy of Polyphenols and Their Combinations. Nutrients. 2016 Sep 9;8(9):552. 

Rauf A, Imran M, Khan IA, et al. Anticancer potential of quercetin: A comprehensive review. Phytother Res. 2018 Nov;32(11):2109-2130. 

Harwood M, Danielewska-Nikiel B, Borzelleca JF, Flamm GW, Williams GM, Lines TC. A critical review of the data related to the safety of quercetin and lack of evidence of in vivo toxicity, including lack of genotoxic/carcinogenic properties. Food Chem Toxicol. 2007 Nov;45(11):2179-205.

Jia Q, Cao H, Shen D, Li S, Yan L, Chen C, Xing S, Dou F. Quercetin protects against atherosclerosis by regulating the expression of PCSK9, CD36, PPARγ, LXRα and ABCA1. Int J Mol Med. 2019 Sep;44(3):893-902.

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