Nearly all of the symptoms associated with allergies can be blamed on inflammatory compounds produced by the immune system, including leukotrienes, prostaglandins, and the major culprit, histamine. Immune cells known as mast cells, that tend to hang out in the skin and mucosal tissues, are the cells primarily responsible for releasing histamine and other inflammatory compounds. In fact, studies show that people who suffer from seasonal allergies have higher numbers of activated mast cells in their nasal passages and respiratory tracts.^{2 3}

The development of allergies is a complicated process, however it can essentially be boiled down to three simple steps. First, an immunological shift occurs so that the immune system begins to recognize allergens as harmful instead of harmless and begins to produce IgE antibodies to things like pollen. Next, these IgE antibodies float throughout the body until a mast cell grabs the antibody and attaches it to the cell’s surface. Now, the mast cell-IgE complex is primed and ready for activation upon encountering the corresponding allergen. Uniquely, mast cells are long lived, and once they obtain an IgE antibody, they can hang out in tissues for months, or even years, waiting to encounter pollen and release histamine.⁴

Do certain fresh fruits or vegetables cause an itching or burning sensation in your lips, mouth, nose, or throat? You may be suffering from something known as oral allergy syndrome—a cross-reactive type of allergy that exists between pollen and certain fruits and vegetables. If you know the source of your particular allergy, you can figure out what fruits or vegetables to avoid. Check out the Children’s Hospital of Philadelphia for more information: http://www.chop.edu/conditions-diseases/oral-allergy-syndrome-oas

While the first step in reducing the likelihood of developing allergies lies within the ability to shift the immune system away from producing IgE antibodies in the first place, for many people it is simply too late and they are looking for more immediate help. Unfortunately many of the typical pharmacological approaches to seasonal allergies and allergic asthma come with unwanted side-effects. Luckily, there are some great nutritional tools that can be used to help tamp down the immune response to pollen and reduce circulating histamine levels.

Acute Support

If you are in the middle of allergy seasonal and in dire need of some relief, there are a few nutrients you can turn to for help. These nutrients are thought to work more directly by decreasing the release of histamine and other inflammatory compounds or increasing histamine degradation.

Vitamin C

While vitamin C is well appreciated for its immune-boosting abilities, it may surprise some that it can also help reduce symptoms of immune reactivity, such as allergies. In fact, carefully controlled studies investigating vitamin C deficiency in humans have demonstrated that as blood levels of vitamin C fall, circulating levels of histamine rise.⁵ It turns out that vitamin C actually enhances the breakdown of histamine by increasing the expression of an enzyme known as diamine oxidase, the enzyme responsible for clearing excess histamine from the body.^{6 7} Studies using vitamin C to combat allergies and asthma typically supplement with 500-1,000 mg per day, split into two doses.⁸

Butterbur

Butterbur has been used in traditional Chinese medicine to treat asthma, migraines, and gastric ulcers—all conditions related to the overproduction of histamine. Studies show that extracts made from butterbur inhibit the release of histamine and other inflammatory mediators from mast cells—suppressing airway inflammation and reducing the magnitude of allergic responses.^{9 10} In one study, a patented butterbur extract was shown to be as effective, or more effective, than several over-the counter or prescription allergy medications.xi Supplement with 20-25 mg of petasins (the active ingredient in butterbur) per day.

Flavonoids

Flavonoids are a group of unique phytonutrients derived from plants. They are mainly known for their antioxidant properties, however, certain flavonoids such as quercetin, luteolin, and rutin suppress histamine release by mast cells, making them useful for reducing allergy symptoms. Research shows these compounds not only inhibit the release of histamine, but also work to restore balance to the immune system, which can provide long-term relief from allergies.¹² In a randomized controlled trial of patients with pollen allergies, taking a supplement containing quercetin and other flavonoids for eight weeks significantly reduced nasal symptoms compared to the placebo group.¹³ Most studies and experts recommend taking between 500 and 2,000 mg of quercetin daily.

Honey

One commonly recommended remedy for seasonal allergies is to consume local, raw honey before and during allergy season. Animal studies indicate that honey can inhibit the ability of mast cells to release histamine upon activation and reduce the amount of inflammation they produce.¹⁴ One interesting human trial compared the effect of consuming one teaspoon per day (about 8 grams) of organic raw honey versus local raw honey and found improvements in both groups compared to the control group, however, the group consuming the local raw honey experienced greater benefit. If you cannot get your hands on local honey, organic raw honey may still help!

Long-Term Solutions

Long-term solutions using the nutrients listed below are less focused on blocking histamine release from mast cells or increasing histamine breakdown, but rather target the underlying cause of allergies—an immune system out of balance. By focusing on restoring this balance, these nutrients can reduce production of IgE antibodies—one of the very first steps in the development of an allergy.

EPA & DHA

The omega-3 fatty acids EPA & DHA are found in fish and also in certain algae and are well known for their systemic anti-inflammatory effects—in part because they counteract the proinflammatory effects of omega-6 fatty acids. One study examined immune cells from people who suffered from seasonal allergies and concluded that those with allergies typically have too many omega-6 fats and too little omega-3 fats in their immune cells.¹⁵ This results in a reduced ability to keep the immune system from needlessly attacking harmless invaders like dust mites or pollen. Furthermore, studies have found that many of the pro-inflammatory signals created by mast cells that exacerbate allergy symptoms can be reduced by displacing omega-6 fats from the cell membrane with omega-3 fats.¹⁶ Studies show there is a dose response when it comes to allergies, and that those who consume more than 800 mg of EPA & DHA per day are the least likely to suffer from allergies.¹⁷

Probiotics

Because the immune systems of children are still developing, using probiotic bacteria to “educate” immune cells to not overreact to harmless molecules like pollen is crucial early in life. Seventy to 80 percent of the immune system is located in the digestive tract, providing an interface between the immune system and probiotics for this type of education. Early-life environmental influences that are known to alter the composition of the gut bacteria—such as antibiotic use, cesarean birth, and formula feeding—have been shown to increase the risk for allergic disease, making these children good candidates for probiotic interventions. Some of the best probiotics for helping to reduce allergies include Lactobacillus casei, lactobacillus rhamonsus GG, lactobacillus plantrum No 14 (LP14), and bifidobacterium longum BB536.¹⁸ Follow directions on product label for dosage.

Greens

Spirulina and chlorella are two of the most common superfoods used to make greens supplements. Both are rich sources of vitamins, minerals, and other phytonutrients. Animal data indicates that spirulina and chlorella supplements are capable of modulating the immune system so that it is less likely to produce IgE molecules, meaning greens supplements are a great way to deal with allergies long term.¹⁹ In one study, 150 participants with a history of allergic rhinitis were given either 2,000 mg of spirulina per day or a placebo and were told not to take any allergy medication during the six-month study period. The group receiving the spirulina had statistically significant reductions in nasal discharge, sneezing, congestion, and itch.²⁰ A 2020 study, revealed that supplementing with 2 grams of spirulina per day for two months improved allergic rhinitis symptoms and quality of life more than the pharmaceutical drug, cetirizine.²¹

Vitamin D

Low vitamin D levels (less than 30 ng/mL) are very common in those with allergies that affect the respiratory tract.²² Most studies have connected this increased risk of allergies to broad changes in the immune system that occur due to the loss of the immune-regulatory effects of vitamin D.²³ Vitamin D shifts the immunological balance so that the immune system is not producing IgE antibodies and also dampens mast cell activation. In fact, mast cells are able to transform vitamin D into its active form, and when they do this, it suppresses their ability to release histamine.²⁴ In general, studies have used doses ranging from 1,000 IU to 4,000 IU of vitamin D daily in order to address allergies.

In Conclusion

Whether you’re looking for immediate relief or trying to fix your immune system by making long-term changes, nutrition represents a viable tool for treating allergies. While over-the-counter and prescription medication for seasonal allergies are advertised as easy and effective, these drugs can frequently have unwanted side effects like drowsiness, dizziness, nausea, and even restlessness and changes in mood. Often nutritional interventions are shown to be as effective as pharmaceuticals for reducing allergy symptoms, without all the side effects. Even better, the nutrients highlighted today not only help with allergies, but also improve overall wellbeing—quite the opposite of over-the-counter drugs.

References

1. http://acaai.org/news/facts-statistics/allergies
2. https://www.karger.com/Article/Abstract/234024
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3597223/
4. http://www.sciencedirect.com/science/article/pii/S0954611111003325
5. https://www.ncbi.nlm.nih.gov/pubmed/8951736
6. https://www.ncbi.nlm.nih.gov/pubmed/25095772
7. Johnston CS. The antihistamine action of ascorbic acid. Subcell Bio- chem 1996;25:189 –213.
8. https://www.ncbi.nlm.nih.gov/pubmed/26453914
9. https://www.ncbi.nlm.nih.gov/pubmed/23711828
10. https://www.ncbi.nlm.nih.gov/pubmed/16608208
11. Dumitru, Alina F.; Shamji, Mohamed; Wagenmann, Martin; Hindersin, Simone; Scheckenbach, Kathrin; Greve, Jens; Klenzner, Thomas; Hess, Lorenzo; Nebel, Sabine; Zimmermann, Christian; Zahner, Catherine; Schmidt-Weber, Carsten B.; Chaker, Adam M. "Petasol butenoate complex (Ze 339) relieves allergic rhinitis–induced nasal obstruction more effectively than desloratadine". Journal of Allergy and Clinical Immunology. 127 (6): 1515–1521.e6
12. https://www.ncbi.nlm.nih.gov/pubmed/23701574
13. https://www.ncbi.nlm.nih.gov/pubmed/19295240
14. Shikawa Y, Tokura T, Nakano N, Hara M, Niyonsaba F, Ushio H, Yamamoto Y, Tado- koro T, Okumura K, Ogawa H: Inhibitory ef- fect of honeybee-collected pollen on mast cell degranulation in vivo and in vitro. J Med Food 2008;11:14–20. 

15. https://www.ncbi.nlm.nih.gov/pubmed/9814727
16. https://www.ncbi.nlm.nih.gov/pubmed/17269555
17. https://www.ncbi.nlm.nih.gov/pubmed/17634174
18. https://www.ncbi.nlm.nih.gov/pubmed/23414544
19. https://www.ncbi.nlm.nih.gov/pubmed/15857205
20. https://www.ncbi.nlm.nih.gov/pubmed/18343939
21. Nourollahian M, Rasoulian B, Gafari A, et al. Clinical comparison of the efficacy of spirulina platensis and cetirizine for treatment of allergic rhinitis. Acta Otorhinolaryngol Ital. 2020 Jun;40(3):224-229. doi: 10.14639/0392-100X-N0139. PMID: 32773785; PMCID: PMC7416373.   
22. https://www.ncbi.nlm.nih.gov/pubmed/25061262
23. https://www.ncbi.nlm.nih.gov/pubmed/22690128
24. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4154631/