Seasonal Allergies? Focus on Antioxidant Support
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Vitamin C and quercetin may help
Although spring brings the joys of warmer days and colorful flowers, it’s also the beginning of allergy season for many (over 19 million of us, to be exact!)For some of us, allergies hit us worse in the fall. Unfortunately, if you have an allergic disposition, it may never seem to end!
Also known as allergic rhinitis, hay fever is a truly irritating condition that occurs when the sinuses and lungs overreact to airborne allergens, including pollen. If you’ve ever had allergies, you know that the symptoms include nasal congestion, sneezing, itchy eyes, coughing, and a runny nose, all of which can lead to headache, sleep disturbances, and fatigue. Living with allergies can be challenging, especially when symptoms are at their worst.
And it’s not just hay and grasses that cause seasonal allergies. Early-season hay fever sufferers tend to react to tree pollens, such as alder and ash, which are carried in the wind. Late-season hay fever sufferers react more to specific grasses and agriculture crop pollens, which start to emerge early May and continue to around mid-August. It’s not surprising, then, that many people resort to antihistamine and/or steroid medications for most of the spring and summer. Unfortunately, these pharmaceuticals also have side effects such as drowsiness, dizziness, dry mouth, nausea, and more.
So can anything be done to increase one’s resilience to hay fever, without the side effects of pharmaceutical treatments? The answer is ‘yes!’ Targeted nutritional support can help. Today we’ll discuss the importance of antioxidant support with quercetin and vitamin C.
Quercetin is a flavonoid found in many fruits and vegetables, including onions, green tea, apples, cherries, broccoli, tomatoes, berries, and green tea. Owing to its antioxidant properties, quercetin is one of the most powerful flavonoids for protecting the body against reactive oxygen species.,
Quercetin is perhaps best known for its role in taming the histamine response seen in allergic conditions.
The consumption of quercetin is associated with a wide range of immune system benefits, including modulation of allergic responses., Quercetin is perhaps best known for its role in taming the histamine response seen in allergic conditions. If you have an allergy, your immune system overreacts to an allergen by producing a type of antibody called immunoglobulin E (IgE). These antibodies bind to mast cells, causing the release of histamine, which triggers allergic symptoms.
Quercetin counteracts the allergic response by suppressing antigen-specific IgE antibody formation, thereby acting at a very early step in the allergic response.,, Additionally, quercetin inhibits the release of histamine and proinflammatory substances implicated in allergic reactions.,
Along with modulating allergic responses, laboratory studies have shown that quercetin can reduce infectivity of a wide variety of respiratory viruses, including coronaviruses,, which have been in the headlines recently due to an outbreak in China. Interestingly, vitamin C appears to enhance the activity of quercetin, in part by stabilizing the quercetin molecule itself. Vitamin C also has independent and potent effects on immune cells, as discussed below.
Maintaining adequate-to-high levels of vitamin C (ascorbate) intake may help reduce one’s susceptibility to allergies.,, Vitamin C modulates the immune system in multiple ways: it promotes immune tolerance (decreasing reactivity) to allergens, prevents excessive inflammation of sinus tissues, lowers blood levels of histamine,, and reduces oxidative stress (more about this later)., Low dietary and circulating ascorbate levels are associated with allergy susceptibility. Moreover, clinical investigations have shown that histamine levels increase exponentially as ascorbate levels decline.,
We humans are one of the few species on earth that cannot synthesize vitamin C and must therefore rely on nutritional sources – food, beverages, and supplements – to meet the body’s ascorbate needs. Diets that are high in vitamin C-rich fruits and veggies may theoretically provide enough vitamin C, yet studies show that up to 20% of the population may have suboptimal vitamin C levels.,,,
Vitamin C status can be suboptimal even with dietary intakes that are generally regarded as adequate.
The best way to assess vitamin C adequacy is to measure blood (plasma) ascorbate concentrations. Based on this measure, a far greater percentage of the population may have suboptimal vitamin C levels. Low ascorbate levels can be triggered by exposures to air pollution (ozone and particulate matter), smoking (including secondary smoke exposures),,, and nicotine itself. These exposures induce oxidative stress, which causes ascorbate depletion, since vitamin C helps mop up excess free radicals (the oxygen species that damage cells, including white blood cells)., Infections,, diabetes, and many other disease conditions also induce oxidative stress and reduce ascorbate levels. Thus vitamin C status can be suboptimal even with dietary intakes that are generally regarded as adequate.,, Studies suggest that additional vitamin C may be needed during infections, for example, and that an extra daily dose helps shorten the duration of the common cold.
Physical and mental stresses also deplete ascorbate and exacerbate allergies.,, This connection is known as the “adrenal-vitamin C axis.” Here’s how it works: the adrenal glands are responsible for producing cortisol, the hormone that helps us react to and deal with stress., The adrenal glands contain high levels of ascorbate, and the same stress-driven signals that cause the adrenals to secrete cortisol also cause them to release ascorbate into the blood. The more stress we experience, the more likely we are to become deficient in vitamin C. This is why people dealing with high stress levels may benefit from some extra vitamin C in the diet and/or supplement regimen. Vitamin C supplementation is associated with a decreased cortisol response after psychological or physical stress.,, (For more information on adrenal support, check out our article on adrenal fatigue.)
In addition to diet and environmental exposure, genetics plays a role in vitamin C requirements. Scientists have discovered that human genetic variations can impair vitamin C transport and antioxidant enzyme function., Individuals who are carrying these gene variants might require higher-than-normal vitamin C intakes to achieve adequate blood ascorbate levels.
Clearly, regular intake of vitamin C supports good health, in the allergy season and beyond. Because vitamin C is water soluble, it is not stored in the body (unlike fat-soluble vitamins such as vitamin D), so it is important to consume vitamin C every day. However, when vitamin C is provided as the crystalline form in a tablet or aqueous (water) solution, it is susceptible to degradation in the gastrointestinal tract. Moreover, the absorption of vitamin C in the gut is easily saturated, meaning we may not get all we need from a single dose of plain vitamin C.
To address these problems, scientists have developed liposomal formulations of vitamin C, which provide more effective and long-lasting delivery of the active molecule.,, Liposomes are tiny spherical sacs of phospholipid molecules enclosing a water-soluble droplet, which are formulated to carry substances (such as drugs or nutrients) into the tissues. The vitamin C is dissolved in the water-soluble droplet, and then surrounded by the protective phospholipid layer, which protects the ascorbate from premature degradation and improves absorption. Liposomes have been shown to protect vitamin C during transit through the gastrointestinal tract; to minimize potential irritation of the GI tract, which typically accompanies large oral doses of ascorbate; and to increase bioavailability. One clinical study showed 68% higher blood levels of ascorbate after consumption of a liposomal form of vitamin C, compared with an aqueous solution. In addition, the liposomal vitamin C increased the length of time the ascorbate persisted in the blood (measured as the half-life), giving it more time to take action within cells.
Quercetin and vitamin C are important natural antioxidants worth considering as part of your daily supplementation regime, particularly during allergy season. The liposomal form of vitamin C helps boost blood levels of this nutrient. Vitamin D3 supplementation is also crucial, as pre-clinical and clinical studies suggest that insufficient vitamin D is associated with allergy symptoms. For more information on nutrition and allergies, see these additional articles:
- Vitamin D for Your Allergies? The data behind vitamin D for asthma, eczema, and atopic conditions.
- Vitamin C for Allergies. Relief from itchy eyes and wheezy lungs.
- Addressing Allergies: A Multi-Pronged Approach. Strategies for soothing itchy eyes and silencing sneezes.
Note: The information in this post was previously published under the title Nutritional Support for Seasonal Allergies.Click here to see References
 Centers for Disease Control and Prevention. Allergies and Hay Fever [Internet]. Atlanta (GA): U.S. Department of Health and Human Services; 2018 [cited 2020 Jan 27]. Available from: https://www.cdc.gov/nchs/fastats/allergies.htm
 Mlcek J, et al. Quercetin and its anti-allergic immune response. Molecules. 2016 May 12;21(5):623.
 Lakhanpal P, Rai DK. Quercetin: a versatile flavonoid. Internet J Med Update. 2007;2:22-37.
 Xu D, et al. Antioxidant activities of quercetin and its complexes for medicinal application. Molecules. 2019 Mar 21;24(6):1123.
 Kimata M, et al. Effects of luteolin, quercetin and baicalein on immunoglobulin E-mediated mediator release from human cultured mast cells. Clin Exp Allergy. 2000 Apr;30(4):501-8.
 Krystel-Whittemore M, et al. Mast cell: a multi-functional master cell. Front Immunol. 2016 Jan 6;6:620.
 Kumazawa Y, et al. Potential use of dietary natural products, especially polyphenols, for improving type-1 allergic symptoms. Curr Pharm Des. 2014;20(6):857-63.
 Singh A, et al. Dietary polyphenols in the prevention and treatment of allergic diseases. Clin Exp Allergy. 2011 Oct;41(10):1346-59.
 Marzocchella L, et al. Dietary flavonoids: molecular mechanisms of action as anti-inflammatory agents. Recent Pat Inflamm Allergy Drug Discov. 2011 Sep;5(3):200-20.
 Chirumbolo S. The role of quercetin, flavonols and flavones in modulating inflammatory cell function. Inflamm Allergy Drug Targets. 2010 Sep;9(4):263-85.
 Chiang LC, et al. In vitro antiviral activities of Caesalpinia pulcherrima and its related flavonoids. J Antimicrob Chemother. 2003 Aug;52(2):194-8.
 Jo S, et al. Characteristics of flavonoids as potent MERS-CoV 3C-like protease inhibitors. Chem Biol Drug Des. 2019 Dec;94(6):2023-30.
 Yi L, et al. Small molecules blocking the entry of severe acute respiratory syndrome coronavirus into host cells. J Virol. 2004 Oct;78(20):11334-9.
 Kallio J, et al. Vitamin C inhibits Staphylococcus aureus growth and enhances the inhibitory effect of quercetin on growth of Escherichia coli in vitro. Planta Med. 2012 Nov;78(17):1824-30.
 Chang HH, et al. High dose vitamin C supplementation increases the Th1/Th2 cytokine secretion ratio, but decreases eosinophilic infiltration in bronchoalveolar lavage fluid of ovalbumin-sensitized and challenged mice. J Agric Food Chem. 2009 Nov 11;57(21):10471-6.
 Carr AC, Maggini S. Vitamin C and immune function. Nutrients. 2017 Nov 3;9(11):1211.
 Canova C, et al. PM10-induced hospital admissions for asthma and chronic obstructive pulmonary disease: the modifying effect of individual characteristics. Epidemiology. 2012 Jul;23(4):607-15.
 Hagel AF, et al. Intravenous infusion of ascorbic acid decreases serum histamine concentrations in patients with allergic and non-allergic diseases. Naunyn Schmiedebergs Arch Pharmacol. 2013 Sep;386(9):789-93.
 Vollbracht C, et al. Intravenous vitamin C in the treatment of allergies: an interim subgroup analysis of a long-term observational study. J Int Med Res. 2018 Sep;46(9):3640-55.
 Mousavi S, et al. Immunomodulatory and antimicrobial effects of vitamin C. Eur J Microbiol Immunol (Bp). 2019 Aug 16;9(3):73-9.
 Johnston CS, et al. Antihistamine effect of supplemental ascorbic acid and neutrophil chemotaxis. J Am Coll Nutr. 1992 Apr;11(2):172-6.
 Seo JH, et al. Association of antioxidants with allergic rhinitis in children from Seoul. Allergy Asthma Immunol Res. 2013 Mar;5(2):81-7.
 Clemetson CA. Histamine and ascorbic acid in human blood. J Nutr. 1980 Apr;110(4):662-8.
 Tricon S, et al. Nutrition and allergic disease. Clin Exp Allergy Rev. 2006 Sep;6(5):117-88.
 Padayatty SJ, Levine M. Vitamin C: the known and the unknown and Goldilocks. Oral Dis. 2016 Sep;22(6):463-93.
 Johnston CS, et al. Vitamin C status of a campus population: college students get a C minus. J Am Coll Health. 1998 Mar;46(5):209-13.
 Hampl JS, et al. Vitamin C deficiency and depletion in the United States: the third National Health and Nutrition Examination Survey, 1988 to 1994. Am J Public Health. 2004 May;94(5):870-5.
 Tveden-Nyborg P, Lykkesfeldt J. Does vitamin C deficiency increase lifestyle-associated vascular disease progression? Evidence based on experimental and clinical studies. Antioxid Redox Signal. 2013 Dec 10;19(17):2084-104.
 Schleicher RL, et al. Serum vitamin C and the prevalence of vitamin C deficiency in the United States: 2003-2004 National Health and Nutrition Examination Survey (NHANES). Am J Clin Nutr. 2009 Nov;90(5):1252-63.
 Pearson JF, et al. Vitamin C status correlates with markers of metabolic and cognitive health in 50-year-olds: findings of the CHALICE cohort study. Nutrients. 2017;9(8):831.
 Karademirci M, et al. Relationship between smoking and total antioxidant status, total oxidant status, oxidative stress index, vit C, vit E. Clin Respir J. 2018 Jun;12(6):2006-12.
 Jacob RA. Passive smoking induces oxidant damage preventable by vitamin C. Nutr Rev. 2000 Aug;58(8):239-41.
 Paunović MG, et al. Protective effects of quercetin and vitamin C against nicotine-induced toxicity in the blood of Wistar rats. Arh Hig Rada Toksikol. 2016 Dec 1;67(4):304-10.
 Ali SS, et al. Understanding oxidants and antioxidants: classical team with new players. J Food Biochem. 2020 Jan 20:e13145.
 Jin X, et al. Amelioration of particulate matter-induced oxidative damage by vitamin C and quercetin in human bronchial epithelial cells. Chemosphere. 2016 Feb;144:459-66.
 Myint PK, et al. Plasma vitamin C concentrations and risk of incident respiratory diseases and mortality in the European Prospective Investigation into Cancer-Norfolk population-based cohort study. Eur J Clin Nutr. 2019 Nov;73(11):1492-1500.
 Chen Y, et al. Vitamin C mitigates oxidative stress and tumor necrosis factor-alpha in severe community-acquired pneumonia and LPS-induced macrophages. Mediators Inflamm. 2014;2014:426740.
 Wilson R, et al. Inadequate vitamin C status in prediabetes and type 2 diabetes mellitus: associations with glycaemic control, obesity, and smoking. Nutrients. 2017 Sep 9;9(9):997.
 Frei B, et al. Authors’ perspective: what is the optimum intake of vitamin C in humans? Crit Rev Food Sci Nutr. 2012;52(9):815-29.
 Lindblad M, et al. Regulation of vitamin C homeostasis during deficiency. Nutrients. 2013 Jul 25;5(8):2860-79.
 Jayedi A, et al. Dietary antioxidants, circulating antioxidant concentrations, total antioxidant capacity, and risk of all-cause mortality: a systematic review and dose-response meta-analysis of prospective observational studies. Adv Nutr. 2018 Nov 1;9(6):701-16.
 Ran L, et al. Extra dose of vitamin C based on a daily supplementation shortens the common cold: a meta-analysis of 9 randomized controlled trials. Biomed Res Int. 2018 Jul 5;2018:1837634.
 Gotovina J, et al. Elevated oxytocin and noradrenaline indicate higher stress levels in allergic rhinitis patients: implications for the skin prick diagnosis in a pilot study. PLoS One. 2018 May 29;13(5):e0196879.
 Chen E, Miller GE. Stress and inflammation in exacerbations of asthma. Brain Behav Immun. 2007 Nov;21(8):993-9.
 Stauder A, Kovács M. Anxiety symptoms in allergic patients: identification and risk factors. Psychosom Med. 2003 Sep-Oct;65(5):816-23.
 Hooper MH, et al. The adrenal-vitamin C axis: from fish to guinea pigs and primates. Crit Care. 2019 Jan 28;23(1):29.
 Padayatty SJ, et al. Human adrenal glands secrete vitamin C in response to adrenocorticotrophic hormone. Am J Clin Nutr. 2007 Jul; 86(1):145-9.
 Patak P, et al. Vitamin C is an important cofactor for both adrenal cortex and adrenal medulla. Endocr Res. 2004 Nov;30(4):871-5.
 Brody S, et al. A randomized controlled trial of high dose ascorbic acid for reduction of blood pressure, cortisol, and subjective responses to psychological stress. Psychopharmacology (Berl). 2002 Jan;159(3):319-24.
 Olayaki LA, et al. Vitamin C prevents sleep deprivation-induced elevation in cortisol and lipid peroxidation in the rat plasma. Niger J Physiol Sci. 2015 Dec 20;30(1-2):5-9.
 Cai Y, et al. A new mechanism of vitamin C effects on A/FM/1/47(H1N1) virus-induced pneumonia in restraint-stressed mice. Biomed Res Int. 2015;2015:675149.
 Shaghaghi MA, et al. Genetic variation in human vitamin C transporter genes in common complex diseases. Adv Nutr. 2016 Mar 15;7(2):287-98.
 Michels AJ, et al. Human genetic variation influences vitamin C homeostasis by altering vitamin C transport and antioxidant enzyme function. Annu Rev Nutr. 2013;33:45-70.
 Chambial S, et al. Vitamin C in disease prevention and cure: an overview. Indian J Clin Biochem. 2013 Oct;28(4):314-28.
 Lykkesfeldt J, Tveden-Nyborg P. The pharmacokinetics of vitamin C. Nutrients. 2019 Oct 9;11(10):2412.
 Hickey S, et al. Pharmacokinetics of oral vitamin C. J Nutr Environ Med. 2008 Jan 1;17(3):169-77.
 Łukawski M, et al. New oral liposomal vitamin C formulation: properties and bioavailability. J Liposome Res. 2019 Jul 2:1-8.
 Wechtersbach L, et al. Liposomal stabilization of ascorbic acid in model systems and in food matrices. LWT-Food Science and Technology. 2012 Jan 1;45(1):43-9.
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Marina MacDonald, MS, PhD
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