WHY QUERCETIN?
Winter 2025 is shaping up to be a challenging season for many.
I’m seeing an upsurge of viruses, including a resurgence of SARS-CoV-2 infections, people diagnosed with both A and B influenza strains seeking help, as well as infectious respiratory syncytial virus (RSV), which presents as a bad cold.
I’m also working with a growing group of people with post viral fatigue, and clients who never fully recovered from virus infections.
It’s got to the stage that we can no longer be complacent about building and maintaining our ability to protect our immune system at all times.
That’s why I want to introduce you to immune boosting Quercetin [KWER-se-tin].
And I’ve created two drink recipes rich in quercetin, one for prevention and the other to support recovery from virus infections.
WHAT IS QUERCETIN?
Quercetin is an immune protector; a nutrient called a flavanol, that belongs to a larger group of plant compounds called flavonoids, from the flavonoid group of polyphenols.
FLAVONOIDS are well known for their powerful antioxidant (protects your cells from damage caused by unstable molecules called free radicals) and anti-inflammatory (reduces inflammation) properties.
POLYPHENOLS are naturally occurring plant nutrients (phytonutrients/phytochemicals) that give plants their different colours, smells, and health benefits.
Think of the rich colour and delicious aroma of freshly ground coffee beans, matcha green tea, ripe berries, crispy apples, vanilla pods, and fresh herbs. It’s polyphenols you’re seeing and smelling.
In nutrition science, quercetin is highly studied in the treatment of inflammatory diseases, diabetes, viruses, cancers, as well as cardiovascular and neurodegenerative diseases.
ANTIVIRAL ELDERBERRY
As a practitioner, I use flavonoids for their antiviral activity against various viruses (DNA and RNA), and for influenza management.
Many studies have established that quercetin has antiproliferative (suppresses growth, spread), antioxidative, anti-inflammatory, antibacterial, antifungal, and antiviral effects.
As an antiviral, quercetin is able to inhibit the initial stages of virus infection to stop it from spreading, and reduce inflammation caused by infection.
One quercetin-rich flavonoid I widely recommend for all virus infections and influenza is elderberry because it’s more palatable for most people, and suitable for all ages from 2 years old upwards.
I use a practitioner strength extract of 1000mg of elderberry per 1ml of extract to get the best results for my clients for both virus prevention and recovery programs.
In the following drink recipes, I combine elderberry extract with prebiotic Nourish powder, organic mulberry juice, MCT coconut oil, and a squeeze of lemon juice.
These ingredients are powerful antivirals, and when combined also boost the absorption and action of quercetin.
RECIPE INGREDIENTS
ELDERBERRY EXTRACT
Studies demonstrate that black elderberry (Sambucus nigra) has proven anti-influenza, antiviral, and antimicrobial effects on respiratory pathogens (disease causing organisms).
The biological activities of elderberry include antioxidant, immunostimulatory, anti-inflammatory, anti-allergic, neuroprotective, anticancer, antibacterial, and antiviral properties.
I use a high potency 1:1 elderberry extract in the drink recipes for its higher concentrations of the active beneficial properties, to gain faster absorption and effectiveness.
NOURISH
I also added Nourish prebiotic powder to the recipe to feed and strengthen your gut microbiome (the home of your immune system).
A healthy gut microbiome is essential for building and maintaining a strong immune system.
Plus, the water-soluble dietary fibre in Nourish enhances quercetin bioavailability (the amount able to be absorbed and used by your body).
LEMON JUICE
Vitamin C also enhances quercetin absorption, which is why I have added lemon juice to your drink recipe.
To further boost the antioxidant potency of your drink, you can also add a half teaspoon of lemon peel zest to your drink.
The limonene in lemon peel is studied for its potential to limit the severity and progression of severe acute respiratory viruses because of its immunomodulatory (regulates the immune system), anti-inflammatory, and antiviral properties.
I’ve included live linked study references at the end of the blog, if you’re interested in exploring the benefits of the recipe ingredients.
MULBERRY JUICE
I recommend using organic cold-pressed black mulberry juice in your drink recipe because of its antioxidant, antiviral, antibacterial, antifungal, and immune regulation properties.
Mulberry is studied for its many health benefits including lung infections, influenza, viral pneumonia, and norovirus (viral gastroenteritis, stomach flu).
In Australia, organic cold-pressed Mulberry juice is available locally from health food shops and organic grocery stores.
You could also be cheeky and ask your local store to order some in for you.
I buy Georgia’s Natural Organic Mulberry Juice, which is made from 100% freshly cold pressed organic fruit.
Georgia’s juices are not made from concentrates (reconstituted) and are free from additives.
If you cannot find pure organic mulberry juice, then I would recommend using antioxidant-rich cold pressed, unsweetened, organic blueberry, blackberry, pomegranate (tart), or blackcurrant juice (slightly tart).
MCT COCONUT OIL
Foods with high concentrations of quercetin are not always the most bioavailable (absorbable).
BUT clinical studies have found dietary fat significantly improves quercetin absorption because quercetin is fat-soluble.
Fat-soluble means certain nutrients are dissolved and better absorbed into your body when you take them with healthy dietary fats.
To boost quercetin absorption, I’ve added 1 teaspoon of mild-tasting MCT coconut oil to both drink recipes.
MCT coconut oil is not only a healthy dietary fat but has been shown to have antimicrobial and antifungal effects.
If you are allergic to coconut, use 1 teaspoon of organic cold pressed hemp seed oil.
QUERCETIN PREVENTION RECIPE
Our quercetin prevention drink recipe can be taken every day of the week if you are rundown or surrounded by people with flu or virus.
Or, to boost your immune system throughout winter, drink it three times a week.
This recipe is designed for adult dosage but is generally safe to use for the whole family.
The only ingredients you will need to adjust are the elderberry extract and Nourish prebiotic powder according to age:
Infants 2-10 yrs: use 10 drops of elderberry 1:1 extract and a quarter teaspoon of Nourish.
Children 10yrs+: use 2.5 ml of elderberry 1:1 extract and half a teaspoon of Nourish.
Adults: use 5ml of elderberry 1:1 extract and a teaspoon of Nourish.
If you are unsure about the dosage for your children, contact your naturopath for advice.
And if you have fussy-food children, create a fun drink by using organic blueberry juice because it’s sweeter and more palatable for young taste buds but still rich in antioxidants.
You can even add organic activated almond milk or Bonsoy soy milk and pretend you’ve made a special mocktail for them. Dress their drink with a brightly coloured cocktail umbrella and a few fresh berries for extra appeal.
ADULT STRENGTH INGREDIENTS
50ml of organic cold-pressed mulberry juice.
5ml of elderberry 1:1 liquid extract.
1 flat teaspoon of Nourish prebiotic powder.
1 teaspoon of MCT coconut oil.
1 generous squeeze of fresh lemon juice.
OPTIONAL
½ teaspoon of lemon zest.
INSTRUCTIONS
Add all ingredients to a glass and use a handheld drink frother to thoroughly blend the ingredients together.
If you need sweetener, use a teaspoon of raw honey or pure monk fruit.
Drink once per day, in the morning, about 15 minutes before you eat food.
QUERCETIN RECOVERY RECIPE
To help your body overcome a viral infection, drink the recovery recipe three times a day until the symptoms are gone, which can take up to ten days.
Then reduce the recovery drink to once or twice a day while you rebuild your immune strength.
This recipe is designed for adult dosage but is generally safe to use for the whole family.
The only ingredients you will need to adjust are the elderberry extract and Nourish prebiotic powder according to age:
Infants 2-10 yrs: use 10 drops of elderberry 1:1 extract and a quarter teaspoon of Nourish.
Children 10yrs+: use 2.5 ml of elderberry 1:1 extract and half a teaspoon of Nourish.
Adults: use 5ml of elderberry 1:1 extract and one flat teaspoon of Nourish.
If you are unsure about the dosage for your children, contact your naturopath for advice.
ADULT STRENGTH INGREDIENTS
50ml of organic cold-pressed mulberry juice.
5ml of elderberry 1:1 liquid extract.
1 flat teaspoon of Nourish prebiotic powder.
1 teaspoon of MCT coconut oil.
The juice of half a fresh lemon.
1 teaspoon of lemon zest (adults only, not children).
1 teaspoon of raw honey.
INSTRUCTIONS
Add all ingredients to a glass and use a handheld drink frother to thoroughly blend the ingredients together.
Drink three times spread throughout the day, about 15 minutes before you eat food until the symptoms are gone.
QUERCETIN RICH FOODS
High concentrations of quercetin are found in fewer foods, but small quantities are found in many fruits, berries, vegetables, leaves, herbs, seeds and grains.
I’ve listed some of the higher quercetin-rich foods below.
To further boost your immune strength, eat at least 1 cup a day of quercetin-rich foods, eaten together with healthy fats to enhance quercetin absorption.
I share beautiful dressing recipes in our free Vegetables e-book that show you how to eat healthy fats with salad ingredients.
You can also add organic Greek or ‘live’ cultured coconut yoghurt, or MCT coconut oil to fruit smoothies, fruit salad, and berry breakfast bowls to boost quercetin absorption.
VEGETABLES
Asparagus.
Broccoli.
Cruciferous vegetables (see our free Vegetables e-book, Chapter 2).
Dark leafy greens.
Green beans.
Kale.
Mushrooms – shiitake, turkey tail, and chaga.
Okra.
Onions.
Radicchio – red cabbage.
Red leaf lettuce.
Red onion.
Shallots.
Spring onions.
Watercress.
Wild rocket.
BERRIES
Chokeberries (Aronia).
Elderberries, black.
Blueberries.
Blackberries.
Cranberries.
Blackcurrant berries.
Lingonberries.
FRUIT
Cherries.
Citrus peel, orange and lemon.
Fig.
Fuji apple.
Gala apple.
Golden kiwi fruit.
Granny smith apple.
Grapes, dark.
Mango.
Plums, black.
Red delicious apple.
HERBS & CONDIMENTS
Capers are the richest source of quercetin of all foods. Raw capers provide up to 234 mg of quercetin per 100 grams. While capers in brine can provide up to 173 mg of quercetin.
Add chopped capers to your salad dressings or sprinkle them over salads to boost your antioxidant intake.
Other herbs and condiments rich in quercetin include:
Chilli peppers, ancho and serrano.
Cloves.
Coriander (cilantro).
Dill.
Fennel leaves.
Juniper berries.
Lovage leaves, raw.
Olive oil.
Oregano, Mexican.
Parsley.
Vinegar, unpasteurised with mother.
NUTS & SEEDS
Almonds.
Pistachios.
Chia seeds.
Pumpkin seeds.
GRAINS & LEGUMES
Buckwheat.
Red kidney beans.
BEVERAGES
Black tea.
Coffee – organic, light roasted.
Ginko biloba tea.
Green tea.
Hawthorn berry tea.
Oolong tea, black.
Passionflower tea.
Raw cacao hot chocolate, use plant-based milk only for better absorption.
Red wine, organic only.
St John’s wort tea.
PRACTITIONER SUPPORT
Poor immune function is often a sign of poor nutrition, a lack of diversity and balance of beneficial microorganisms in your gut, and chronic stress.
You need to eat well to be well, nourish your gut microbiome, and learn skills to help you manage stress – including exercise, meditation, and mindful living.
The quercetin drink recipes and food list are designed for general use to help strengthen your immune system and gut microbiome.
If you need further support recovering from a severe virus infection or influenza, our practitioners can help you with more intense immune recovery programs.
And if you are ill, we can even organise zoom or phone consultations with our practitioners.
Because I’m using practitioner strength elderberry extract in the recipes, you will need a script. But this can be easily organised by calling or emailing us at admin@renerhc.com.au.
Or pop into the clinic to see us.
We love catchups and supporting you.
All the very best.
Stay strong and healthy this winter.
Much love,
Lisa Rieniets ND.
RECIPE SHEET DOWNLOAD
You can download our QUERCETIN Immune Drink Recipes Handout Sheet and food list by clicking on the link.
It’s free of charge, and please share it with family and friends so we can all stay strong and healthy this winter.
RELATED BLOGS
Free E-Book Download: Nutrition Therapy – VEGETABLES
https://www.renerhealthclinics.com.au/free-e-books-health-healing/
Nutrition Therapy – HEALTHY FATS
https://www.renerhealthclinics.com.au/nutrition-therapy-healthy-fats/
NOURISH Prebiotic Breakfast Drink Powder
https://www.renerhealthclinics.com.au/nourish-prebiotic-breakfast-drink/
Your Gut Microbiome & Why Prebiotics Are Essential
https://www.renerhealthclinics.com.au/gut-microbiome-prebiotics/
REFERENCES
I love sharing studies you can dive into and learn more about the amazing benefits eating healthy food can create.
Food is our fuel and a primary source of our health.
What we choose to eat every day matters.
QUERCETIN
Aghababaei F, Hadidi M. Recent Advances in Potential Health Benefits of Quercetin. Pharmaceuticals. 2023; 16(7):1020. https://doi.org/10.3390/ph16071020
Amanzadeh E, Esmaeili A, Rahgozar S, Nourbakhshnia M. Application of quercetin in neurological disorders: from nutrition to nanomedicine. Rev Neurosci. 2019 Jul 26;30(5):555-572. doi: 10.1515/revneuro-2018-0080. PMID: 30753166. (Neurological disorders)
Bayazid AB, Lim BO. Quercetin Is An Active Agent in Berries against Neurodegenerative Diseases Progression through Modulation of Nrf2/HO1. Nutrients. 2022 Dec 2;14(23):5132. doi: 10.3390/nu14235132. PMID: 36501161; PMCID: PMC9737775. (Neurodegenerative Diseases)
Colunga Biancatelli RML, Berrill M, Catravas JD, Marik PE. Quercetin and Vitamin C: An Experimental, Synergistic Therapy for the Prevention and Treatment of SARS-CoV-2 Related Disease (COVID-19). Front Immunol. 2020 Jun 19;11:1451. doi: 10.3389/fimmu.2020.01451. PMID: 32636851; PMCID: PMC7318306. (Quercetin + vitamin C)
Di Petrillo A, Orrù G, Fais A, Fantini MC. Quercetin and its derivates as antiviral potentials: A comprehensive review, Phytother Res. 2022 Jan;36(1):266-278. doi: 10.1002/ptr.7309. Epub 2021 Oct 28. PMID: 34709675; PMCID: PMC8662201. (Antiviral Quercetin)
Li Y, Yao J, Han C, Yang J, Chaudhry MT, Wang S, Liu H, Yin Y. Quercetin, Inflammation and Immunity. Nutrients. 2016 Mar 15;8(3):167. doi: 10.3390/nu8030167. PMID: 26999194; PMCID: PMC4808895. (Food sources)
Mehrbod P, Hudy D, Shyntum D, Markowski J, Łos MJ, Ghavami S. Quercetin as a Natural Therapeutic Candidate for the Treatment of Influenza Virus. Biomolecules. 2020 Dec 24;11(1):10. doi: 10.3390/biom11010010. PMID: 33374214; PMCID: PMC7824064. (Quercetin for influenza)
Panche AN, Diwan AD, Chandra SR. Flavonoids: an overview. J Nutr Sci. 2016 Dec 29;5:e47. doi: 10.1017/jns.2016.41. Erratum in: J Nutr Sci. 2025 Jan 29;14:e11. doi: 10.1017/jns.2024.73. PMID: 28620474; PMCID: PMC5465813. (Flavonoids)
Shorobi FM, Nisa FY, Saha S, Chowdhury MAH, Srisuphanunt M, Hossain KH, Rahman MA. Quercetin: A Functional Food-Flavonoid Incredibly Attenuates Emerging and Re-Emerging Viral Infections through Immunomodulatory Actions. Molecules. 2023 Jan 17;28(3):938. doi: 10.3390/molecules28030938. PMID: 36770606; PMCID: PMC9920550.(Antiviral, anti-influenza quercetin)
Wu W, Li R, Li X, He J, Jiang S, Liu S, Yang J. Quercetin as an Antiviral Agent Inhibits Influenza A Virus (IAV) Entry. Viruses. 2015 Dec 25;8(1):6. doi: 10.3390/v8010006. PMID: 26712783; PMCID: PMC4728566. (Quercetin Inhibits influenza)
Yang D, Wang T, Long M, Li P. Quercetin: Its Main Pharmacological Activity and Potential Application in Clinical Medicine. Oxid Med Cell Longev. 2020 Dec 30;2020:8825387. doi: 10.1155/2020/8825387. PMID: 33488935; PMCID: PMC7790550. (Quercetin activity)
INFLAMMATION
InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. In brief:What is an inflammation? [Updated 2025 Apr 11]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279298/
ELDERBERRY
Pascariu O-E, Israel-Roming F. Bioactive Compounds from Elderberry: Extraction, Health Benefits, and Food Applications. Processes. 2022; 10(11):2288. https://doi.org/10.3390/pr10112288
Sidor, Andrzej. (2017). Berries as a potential anti-influenza factor – A review. Journal of Functional Foods. 37. 116-137. 10.1016/j.jff.2017.07.050. (Anti-influenza)
Sidor, Andrzej & Gramza Michalowska, Anna. (2014). Advanced research on the antioxidant and health benefit of elderberry (Sambucus nigra) in food – a review. Journal of Functional Foods. 18. 10.1016/j.jff.2014.07.012.
Vujanović M, Majkić T, Zengin G, Beara I, Tomović V, Šojić B, Đurović S, Radojković M. Elderberry (Sambucus nigra L.) juice as a novel functional product rich in health-promoting compounds. RSC Adv. 2020 Dec 21;10(73):44805-44814. doi: 10.1039/d0ra09129d. PMID: 35516231; PMCID: PMC9058610.
NOURISH
Belkaid Y, Hand TW. Role of the microbiota in immunity and inflammation. Cell. 2014 Mar 27;157(1):121-41. doi: 10.1016/j.cell.2014.03.011. PMID: 24679531; PMCID: PMC4056765. (Inflammation and immunity)
Bosscher D, Breynaert A, Pieters L, Hermans N. Food-based strategies to modulate the composition of the intestinal microbiota and their associated health effects. J Physiol Pharmacol. 2009 Dec;60 Suppl 6:5-11. PMID: 20224145.(Microbiome & health)
Bull MJ, Plummer NT. Part 1: The Human Gut Microbiome in Health and Disease. Integr Med (Encinitas). 2014 Dec;13(6):17-22. PMID: 26770121; PMCID: PMC4566439. (Microbiome & disease)
MULBERRY
Jing J, Sun Y, Shui Y, Wang J, Ye W, Chen R, Wu L, Xing L, Huang R, Zhou T, Zhu W, Wu Y, Zhang S, Shi J, Li Y, Liu Y, You Z. Morus alba L. alleviates influenza viral pneumonia. Evidences of its mechanism of action. Phytomedicine. 2025 May;140:156574. doi: 10.1016/j.phymed.2025.156574. Epub 2025 Feb 26. PMID: 40054181. (Viral pneumonia).
Kim, Hyojin, Chung, Mi Sook, Antiviral Activities of Mulberry (Morus alba) Juice and Seed against Influenza Viruses, Evidence-Based Complementary and Alternative Medicine, 2018, 2606583, 10 pages, 2018. (Influenza)
Lee JH, Bae SY, Oh M, Kim KH, Chung MS. Antiviral effects of mulberry (Morus alba) juice and its fractions on foodborne viral surrogates. Foodborne Pathog Dis. 2014 Mar;11(3):224-9. doi: 10.1089/fpd.2013.1633. Epub 2013 Dec 19.. PMID: 24350883. (Norovirus)
Manzoor MF, Hussain A, Tazeddinova D, Abylgazinova A, Xu B. Assessing the Nutritional-Value-Based Therapeutic Potentials and Non-Destructive Approaches for Mulberry Fruit Assessment: An Overview. Comput Intell Neurosci. 2022 Mar 24;2022:6531483. doi: 10.1155/2022/6531483. Retraction in: Comput Intell Neurosci. 2023 Sep 20;2023:9860875. doi: 10.1155/2023/9860875. PMID: 35371246; PMCID: PMC8970939. (Therapeutic potential)
Sakar, Ebru, Ercisli, Sezai, Marc, Romina Alina, Gulen, Hatice, Assouguem, Amine, Ullah, Riaz, Shahat, Abdelaaty A., Bari, Ahmed and Farah, Abdellah. “Black mulberry (Morus nigra L.) fruits: As a medicinal plant rich in human health-promoting compounds” Open Chemistry, vol. 21, no. 1, 2023, pp. 20220323. https://doi.org/10.1515/chem-2022-0323
ENHANCE ABSORPTION
Aghababaei F, Hadidi M. Recent Advances in Potential Health Benefits of Quercetin. Pharmaceuticals (Basel). 2023 Jul 18;16(7):1020. doi: 10.3390/ph16071020. PMID: 37513932; PMCID: PMC10384403. (Importance dietary fat for absorption)
Dabeek WM, Marra MV. Dietary Quercetin and Kaempferol: Bioavailability and Potential Cardiovascular-Related Bioactivity in Humans. Nutrients. 2019; 11(10):2288. https://doi.org/10.3390/nu11102288 (Dietary fats enhance absorption)
Duranova, H., Kuzelova, L., Fialkova, V. et al. Coconut-sourced MCT oil: its potential health benefits beyond traditional coconut oil. Phytochem Rev 24, 659–700 (2025). https://doi.org/10.1007/s11101-024-09969-1 (MCT coconut oil, antibacterial)
Kaşıkcı M. B, Bağdatlıoğlu N. Bioavailability of Quercetin. Curr Res Nutr Food Sci 2016;4(Special Issue Confernce October 2016). http://www.foodandnutritionjournal.org/?p=2963. (Lemon juice, vitamin C)
Nagoor Meeran MF, Seenipandi A, Javed H, Sharma C, Hashiesh HM, Goyal SN, Jha NK, Ojha S. Can limonene be a possible candidate for evaluation as an agent or adjuvant against infection, immunity, and inflammation in COVID-19? Heliyon. 2020 Dec 11;7(1):e05703. doi: 10.1016/j.heliyon.2020.e05703. PMID: 33490659. PMCID: PMC7810623. (Lemon peel)
Trakooncharoenvit A, Tanaka S, Mizuta E, Hira T, Hara H. Water-soluble dietary fibers enhance bioavailability of quercetinand a fiber derived from soybean is most effective after long-term feeding in rats. Eur J Nutr. 2020 Jun;59(4):1389-1398. doi: 10.1007/s00394-019-01992-9. Epub 2019 May 11. PMID: 31079173. (Dietary fibre for absorption)
QUERCETIN RICH FOODS
Górecki M, Hallmann E. The Antioxidant Content of Coffee and Its In Vitro Activity as an Effect of Its Production Method and Roasting and Brewing Time. Antioxidants (Basel). 2020 Apr 10;9(4):308. doi: 10.3390/antiox9040308. PMID: 32290140; PMCID: PMC7222172. (Organic coffee)
Manzoor, Muhammad. (2018). Quercetin-A Mini Review, Mod Concep Dev Agrono. 1(2). MCDA.000507. 2018. (Quercetin levels in foods)