The Gut-Allergy Connection

Antihistamines

Antihistamines block histamine receptors, reducing symptoms like sneezing, itching, runny nose, and watery eyes. Second-generation antihistamines (cetirizine, fexofenadine, loratadine) are preferred because they cause less drowsiness than older options like diphenhydramine.

Best for: mild to moderate symptom relief, acute flares

Limitation: they block histamine after it is released - they do not address why your immune system is overproducing it

Intranasal corticosteroid sprays

Nasal steroid sprays (like fluticasone and triamcinolone, available OTC) are considered the most effective first-line treatment for moderate to severe allergic rhinitis by the American Academy of Allergy, Asthma and Immunology. They work by reducing inflammation in the nasal passages.

Best for: persistent nasal symptoms, congestion, postnasal drip

Important note: they work best when started 1-2 weeks before allergy season begins and used consistently, not just on symptomatic days

Nasal irrigation

Saline nasal rinses - whether you use a neti pot or a squeeze bottle - help wash out allergens, mucus, and other irritants from your nose. Studies show that using them regularly can ease symptoms and may even help you rely less on allergy medications.

Tip: always use distilled or sterile water, never tap water, to avoid introducing pathogens.

→ Recommended Product — Navage Nasal Irrigation Kit

Air quality management

Reducing your allergen exposure at home is one of the most underrated parts of seasonal allergy management. High-efficiency particulate air (HEPA) filters can significantly reduce indoor pollen, dust mites, pet dander, and mold spores.

• Look for a HEPA air purifier rated for your room size

• Change HVAC filters regularly during peak season

• Keep windows closed on high-pollen days and shower after outdoor time

→ Recommended Product — SPLURGE! Shark NeverChange Air Purifier

→Recommended Product — SAVE! Levoit Air Purifier

Allergen immunotherapy

For people with moderate to severe allergic rhinitis that doesn’t improve enough with medications, allergen immunotherapy (allergy shots or under‑the‑tongue tablets) is the only treatment that actually changes how the immune system reacts.

It works by slowly exposing the body to small, increasing amounts of the allergen so the immune system becomes more tolerant over time.

This treatment takes commitment, usually 3 to 5 years, but it can lead to long‑lasting relief and, for some patients, even remission.

If you feel like you have tried everything and are still struggling, immunotherapy is worth a conversation with an allergist.

Probiotics

Certain probiotic strains have been studied for their effects on allergic rhinitis. The strongest evidence is for Lactobacillus and Bifidobacterium species.

A 2022 meta‑analysis published in the International Archives of Allergy and Immunology found that taking probiotics was linked to meaningful improvements in allergy symptoms and a better overall quality of life.

Not all probiotics are created equal - strain matters. Strains with the strongest evidence for allergic disease include:

• Lactobacillus rhamnosus GG

• Lactobacillus acidophilus NCFM

• Bifidobacterium lactis Bl-04

If you are considering a probiotic for allergy support, look for a product that lists specific strains, CFU count at expiration (not just at manufacture), and has third-party testing.

Prebiotics and dietary fiber

Probiotics need fuel. Prebiotics (found in foods like garlic, onions, leeks, asparagus, bananas, and oats) feed the good gut bacteria and support diversity. 

Eating more dietary fiber is linked to a healthier, more diverse gut microbiome, and people who eat more fiber tend to have lower rates of allergic diseases.

Aim for 25-35 grams of fiber per day from whole food sources. Most Americans get less than half that!

Quercetin

Quercetin is a naturally occurring flavonoid found in apples, onions, capers, and berries. It has both antihistamine and anti-inflammatory properties, and research suggests it may help stabilize mast cells - the immune cells responsible for releasing histamine.

Quercetin phytosome is significantly more bioavailable than plain quercetin.

Vitamin D

Vitamin D deficiency is strongly associated with increased allergic disease severity (among many other things!). Vitamin D receptors are found on nearly every immune cell. Many patients with poorly controlled allergies are also vitamin D deficient. In fact, it is one of the most common nutrient deficiencies in the US.

Getting your vitamin D level tested (via a simple blood test) is a reasonable first step before supplementing.

Omega-3 fatty acids

Omega‑3s - especially EPA and DHA, which are found in fatty fish and fish oil supplements - are well‑known for their anti‑inflammatory effects. Research suggests they can help lower the production of inflammatory compounds that contribute to allergic reactions. They also help support a healthy gut lining! 

Hematology note: If you are taking a blood-thinner, take omega-3 fatty acids with caution. High amounts of omega-3s can make your blood even thinner.

Dietary patterns

The Mediterranean diet (you should have known you’d see this term again!) - rich in vegetables, fruits, legumes, whole grains, olive oil, and fish - is consistently associated with lower rates of allergic disease. Its combination of high fiber, polyphenols, and omega-3s supports a diverse microbiome and a less inflammatory immune environment.

Conversely, ultra-processed foods, excess sugar, and a low-fiber diet are associated with microbiome disruption and worsened allergy outcomes (and cancer!). 

This does not mean you need to overhaul everything overnight! In fact, please don’t. Small, consistent shifts toward whole foods make a meaningful difference that you can actually sustain.