Heather Bray, RD
Nutrition and Seasonal Allergies, is there a connection?
How can nutrition help with seasonal allergies?
*Disclaimer: the views and opinions of this article are based on the best available evidence and my professional opinion as a Registered Dietitian. This article is not meant to act as a substitute for medical or medical nutrition advice. For medical or medical nutrition advice that is designed for your individual needs, please consult your doctor or Registered Dietitian.
It’s that time of year where everyone is excited to get outside and enjoy the warmer weather. Unfortunately for an estimated 10-40% of people affected by seasonal allergies, this time of year can be difficult to manage because of these symptoms (1). Over the past few years there has been an increased interest around food and how it can impact the immune system. The questions around this time of year are - How can my diet impact my seasonal allergies? Are there foods that I should be avoiding? What foods should I have more of?
I’ve done a deep dive into this topic, so read below to get some answers!
First of all, what are seasonal allergies?
Seasonal allergies manifest as a group of symptoms experienced in the spring and late summer/fall in response to a larger number of particles such as pollen in the air. The symptoms of seasonal allergies (AKA Hay Fever or Allergic Rhinitis) such as runny and itchy nose, sneezing, coughing etc. are caused by an immune system response to these particles (1). When the nose, mouth, throat and lungs encounter particles such as pollen, the immune system releases histamine which causes the unwanted symptoms listed above.
What is histamine?
Histamine is the chemical released in the body in response to the perceived threat of pollen, dust, pet dander, dust mites, mold, ragweed etc. When immune cells in the body detect the compound that you’re allergic to (e.g. pollen), they send messages to the body to release histamine which is the compound responsible for common allergy symptoms such as coughing, sneezing, itchy eyes and sore throat (2).
Interestingly, histamine is not only responsible for the all too familiar allergy symptoms, it also plays a role in our sleep-wake cycle, memory, emotions, body temperature and much more (3).
How does the food we eat interact with allergies?
First of all, can food cure or prevent seasonal allergies? No.
But the food you eat may help (along with other lifestyle choices) in decreasing the intensity and duration of the symptoms associated with seasonal allergies.
What foods should we have more of?
There are a lot of foods that help support the immune system. For starters, simply getting enough to eat each day can impact the immune system. Under-eating can lead to nutrient deficiencies and can affect the body’s ability to respond to threats such as viruses and allergens.
If you’re wondering whether or not you’re getting enough to eat each day, consider going through a nutrition assessment with a Registered Dietitian.
It is also important to look at the diet as a whole when we think about strategies to reduce seasonal allergies. An anti-inflammatory diet can help with reducing the total amount of inflammation that occurs in the body as a result of seasonal allergies. This is just one of the many benefits offered by an anti-inflammatory diet such as the Mediterranean or MIND diets.
Foods To Eat To Help Decrease Inflammation:
All fruits and vegetables. This is due to the colour pigments in plants called phytochemicals whose job is to help fight inflammation in the body.
Spices and herbs such as: cinnamon, black pepper, parsley, basil, turmeric, ginger, paprika, cardamom
Oily fish such as salmon, trout, sardines, mackerel, arctic char and anchovies.
Nuts and seeds such as, Brazil nuts, walnuts, chia, ground flax and hemp seeds
Beans and lentils
Choosing whole grains (oats, quinoa, whole grain bread products) over refined grains most often
Olive oil
The importance of having a wide variety of foods in your diet cannot be overlooked. Foods such as: fruits, vegetables, nuts, seeds, legumes and whole grains, some dairy products and fish are imperative to optimize the immune system. For example, green vegetables along with avocados and legumes offer B vitamins such as Folate which aid in cell-division, an important cellular function needed for an optimized immune system (4). Orange fruits and vegetables, dairy and fish offer two types of Vitamin A needed in the production of the types of immune cells that protect us (e.g. macrophages and neutrophils) (5). The immune system, just like the rest of our body, is highly complex and relies on many nutrients to function optimally.
Speaking of optimization, the best way to optimize your nutrient intake is through food as opposed to supplements. This is because the nutrients that exist in foods will almost always be more bioavailable in food form.
Vitamin C rich foods may also help with seasonal allergies. This is similar to the ways in which vitamin C helps with the common cold. Contrary to popular belief, Vitamin C does not “boost the immune system”, although it may help with reducing symptoms and the duration of the common cold and allergy symptoms such as sore throat, sneezing and coughing. Vitamin C’s antioxidant and antihistamine properties have been well known (6,7).
Food sources: Bell peppers, broccoli, mango, kiwi, citrus fruits
A note on Vitamin C supplements: if you are going to supplement, try to take the lowest dose possible at different times in the day. You absorb far more vitamin C in smaller doses (250mg-500mg) as opposed to larger ones (1000mg +) (8).
Quercetin is a type of polyphenol that exists in many foods. In lab tests, supplemental quercetin has been shown to inhibit cells from releasing histamine (the allergy symptom causing immune compounds) leading to the thought that taking quercetin supplements can inhibit or at least decrease the release of histamine in the body and therefore help mitigate the allergy response (9). So far, there is no conclusive evidence that the use of quercetin supplements can decrease histamine release in the body or reduce allergy symptoms (10).
If you can, your best bet is to aim to increase your intake of quercetin-rich foods rather than supplements, such as: citrus fruits, apples, onion, tea, sage, parsley, olive oil, berries and cherries.
Probiotic rich foods. The gut microbiome plays a key role in regulating the immune system (11). It has therefore been theorized that a dysregulated gut microbiome may negatively impact the immune system. This is why populating the gut microbiome with prebiotic and probiotic rich foods can be beneficial in colonizing the gut microbiome with good bacteria (11,12).
Prebiotics are types of fibers that exist in foods to help to fuel the probiotics in the gut. Some Prebiotic Rich Foods include:
Legumes such as chickpeas, lentils and red kidney beans
Onions, shallots and garlic
Oats, barley and bran
Bananas and grapefruit
Almonds, pistachios and flaxseed
Leafy greens, cabbage and Jerusalem artichokes
Probiotic Rich Foods include:
Greek yogurt
Kefir
Kimchi
Miso
Tempeh
Kombucha
There was a 2022 Systematic Review and Meta Analysis done to review the impact of probiotic supplements on seasonal allergies. The authors acknowledged that in the studies reviewed, there were mixed results when it came to the effect probiotic supplementation had on reducing seasonal allergies. The authors also state a need for further research in humans to draw conclusions about the use of probiotic supplements in the treatment of seasonal allergies (12). They did, however, discuss the importance of including pre and probiotic rich foods in the diet.
Green tea contains a compound called epigallocatechin gallate (EGCG) which is a phytochemical known to help reduce inflammation (13) . There have also been claims made that the EGCG in green tea acts to inhibit the enzymes that enable cells to produce histamine. This is why drinking green tea may help to reduce the amount of histamine produced by cells and therefore decrease some of the seasonal allergy symptoms people experience (14).
Nutrition and Allergy Myth:
There is a debate between whether or not consuming local honey year round can be helpful in preventing seasonal allergies. It is thought to help because it contains some pollen and this micro-exposure may help make the immune system more resilient come spring time. This, however, has not yet been proven in the literature. There have been some small studies done such as this Randomized Control Trial published in 2013 that showed a correlation between high doses of bee pollen and decreased allergy symptoms (allergic rhinitis) (15). However this 2021 mini-review concluded that, of the studies examined, some showed significant benefit with the use of honey in reducing allergy symptoms and others did not. The authors also acknowledged that there is a need for further research in order to confirm the use of honey in treating seasonal allergies (16).
Honey is known to have anti-inflammatory and antimicrobial effects and can often help with relieving a sore throat when consumed in a hot beverage sugar as tea.
Bottom line: consuming honey on a regular basis has not yet been proven to prevent seasonal allergies, but it is a low-risk intervention and may help with symptom management. Plus honey is a tasty ingredient to add in many foods.
What foods do we need to avoid?
The unfortunate thing about the internet is that if you Google "food to avoid for seasonal allergies” you’ll find a bunch or articles with different lists. It can leave someone feeling very confused and almost asking “what’s left to eat?!”.
As an Intuitive Eating Dietitian, my goal is never to demonize specific food groups or advise folks to eliminate anything. If there is a food that you notice causes your symptoms to increase significantly or causes the oral allergy syndrome reaction mentioned below, I would recommend avoiding that food.
It’s difficult to pinpoint exactly which foods will increase symptoms and/or cause these reactions which is where working with a dietitian and/or keeping a food log can be helpful. I’m not suggesting using a calorie tracker, simply recording what you eat alongside your symptoms can help you identify your specific trigger foods.
A Note on Oral Allergy Syndrome
Do you get a strange sensation on your lips or in your mouth when you eat certain fruits or vegetables? Some people describe this sensation as an itch, swollen lips or tickle in their throat. If so, you may have oral allergy syndrome (aka Pollen Food Allergy Syndrome). Many people with seasonal allergies experience this sensation while eating some produce. It is important to try to pinpoint exactly which foods cause this sensation.
However, thanks to this article by Today’s Dietitian, the following may help you identify some triggers:
Those with an allergy to birch or alder trees may have an oral allergy syndrome reaction to apples, cherries or celery.
Those allergic to grass may have this reaction when they eat: tomatoes, peaches or potatoes (17).
Bottom Line
While the foods you eat and don’t eat may not have the same effect on seasonal allergies as antihistamine medication will, they can certainly aid in symptom management. Remember, there is no one food item that will cure your allergies. Keep a wide variety of food in your diet, get enough rest and talk to your doctor about your seasonal allergies to see if there are any other strategies to consider outside of nutrition.
References
(1) Luo C, Peng S, Li M, Ao X, Liu Z. The Efficacy and Safety of Probiotics for Allergic Rhinitis: A Systematic Review and Meta-Analysis. Front Immunol. 2022 May 19;13:848279. doi: 10.3389/fimmu.2022.848279. PMID: 35663980; PMCID: PMC9161695.
(2) Cleveland Clinic. What Is Histamine?
(3) Cleveland Clinic. Allergic Rhinitis (Hay Fever)
(4) Khan MZ, Khan A, Xiao J, Dou J, Liu L, Yu Y. Overview of Folic Acid Supplementation Alone or in Combination with Vitamin B12 in Dairy Cattle during Periparturient Period. Metabolites. 2020 Jun 25;10(6):263. doi: 10.3390/metabo10060263. PMID: 32630405; PMCID: PMC7344520.
(5) Huang Z, Liu Y, Qi G, Brand D, Zheng SG. Role of Vitamin A in the Immune System. J Clin Med. 2018 Sep 6;7(9):258. doi: 10.3390/jcm7090258. PMID: 30200565; PMCID: PMC6162863.
(6) Carr AC, Maggini S. Vitamin C and Immune Function. Nutrients. 2017 Nov 3;9(11):1211. doi: 10.3390/nu9111211. PMID: 29099763; PMCID: PMC5707683.
(7) Vollbracht C, Raithel M, Krick B, Kraft K, Hagel AF. 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):3640-3655. doi: 10.1177/0300060518777044. Epub 2018 Jun 27. PMID: 29950123; PMCID: PMC6136002.
(8) National Institutes of Health. Vitamin C - Health Professional Fact Sheet
(9) Jafarinia M, Sadat Hosseini M, Kasiri N, Fazel N, Fathi F, Ganjalikhani Hakemi M, Eskandari N. Quercetin with the potential effect on allergic diseases. Allergy Asthma Clin Immunol. 2020 May 14;16:36. doi: 10.1186/s13223-020-00434-0. PMID: 32467711; PMCID: PMC7227109.
(10) Mount Sinai. Quercetin
(11) Zheng, D., Liwinski, T. & Elinav, E. Interaction between microbiota and immunity in health and disease. Cell Res 30, 492–506 (2020). https://doi.org/10.1038/s41422-020-0332-7
(12) Lopez-Santamarina A, Gonzalez EG, Lamas A, Mondragon ADC, Regal P, Miranda JM. Probiotics as a Possible Strategy for the Prevention and Treatment of Allergies. A Narrative Review. Foods. 2021 Mar 25;10(4):701. doi: 10.3390/foods10040701. PMID: 33806092; PMCID: PMC8064452.
(13) Akbarialiabad H, Dahroud MD, Khazaei MM, Razmeh S, Zarshenas MM. Green Tea, A Medicinal Food with Promising Neurological Benefits. Curr Neuropharmacol. 2021;19(3):349-359. doi: 10.2174/1570159X18666200529152625. PMID: 32469701; PMCID: PMC8033961.
(14) Melgarejo E, Medina MA, Sánchez-Jiménez F, Urdiales JL. Targeting of histamine producing cells by EGCG: a green dart against inflammation? J Physiol Biochem. 2010 Sep;66(3):265-70. doi: 10.1007/s13105-010-0033-7. Epub 2010 Jul 22. PMID: 20652470.
(15) Asha'ari ZA, Ahmad MZ, Jihan WS, Che CM, Leman I. Ingestion of honey improves the symptoms of allergic rhinitis: evidence from a randomized placebo-controlled trial in the East coast of Peninsular Malaysia. Ann Saudi Med. 2013 Sep-Oct;33(5):469-75. doi: 10.5144/0256-4947.2013.469. PMID: 24188941; PMCID: PMC6074882.
(16) Front. Pharmacol., 26 January 2021 Sec. Ethnopharmacology Volume 11 - 2020 | https://doi.org/10.3389/fphar.2020.599080
(17) Today’s Dietitian. Five Things That Can Aggravate Your Spring Allergies