Nutritional Strategies for Managing Allergic Rhinitis

Allergic rhinitis often shows up during the spring and fall seasons. Its main symptoms include occasional sneezing, clear runny nose, itchy nose, stuffy nose, and a reduced ability to smell. This condition predominantly affects children but can also impact individuals of all ages, significantly influencing their daily lives as well as their physical and mental well-being.

Mechanisms of Allergic Rhinitis

The primary mechanism underlying allergic rhinitis involves a series of steps: Following exposure to antigens, the immune system becomes sensitized, leading to a notable increase in immunoglobulin E (IgE) levels targeted against these antigens. When antigens like dust mites resurface, IgE attached to mast cells’ surface combines with the antigens, prompting mast cells to release inflammatory factors through degranulation. This process subsequently triggers the symptoms associated with allergic rhinitis.

Among immune cells, CD4+ lymphocytes are commonly referred to as helper T cells. These cells exhibit high adaptability and can mature into either type 1 helper T cells (Th1) or type 2 helper T cells (Th2). Dendritic cells, predominantly found in the intestines, play a vital role as antigen-presenting cells (APCs). When they encounter antigens, they guide helper T cells towards differentiating into Th1 or Th2. The equilibrium between Th1 and Th2 in the immune system influences inflammation and allergic symptoms. When Th1 (and Th17) becomes overly active, it can trigger autoimmune diseases like rheumatoid arthritis and type 1 diabetes within organ tissues. Conversely, excessive Th2 activity can contribute to allergic diseases such as atopic asthma and eczema [1].

Why does the immune system sometimes react excessively to antigen exposure?

The cause of allergic rhinitis is unclear. However, some suggest that dietary factors or antibiotic use can disrupt gut microbiota balance, leading to compromised immune tolerance and an elevated risk of allergic diseases, including rhinitis.

Antibiotic use disrupts gut microbiota balance and heightens rhinitis risk. Abundant research has shown antibiotics increase chances of allergic conditions, including rhinitis. A 2019 study from Louisiana State University Health Sciences Center [2] analyzed patient samples over a decade (2007-2016). Results revealed a 266% higher risk of allergic rhinitis in children exposed to antibiotics before age 1, and a 243% risk for those older than 1. Risk for asthma was even higher at 343%.

More Fruits and Vegetables

In 2007, a study on a European island [3] analyzed diets of 690 children aged 7 to 18. Notably, 80% consumed fresh fruits twice daily, 68% had vegetables. Fruits like grapes, oranges, apples, and tomatoes correlated with lower rhinitis. Plant margarine (trans fats) raised risk. A Mediterranean diet with fruits, vegetables, olive oil linked to 66% lower rhinitis risk. Diet explained lower allergy risk.

Vitamin C and Vitamin D

In a 2013 epidemiological study [4] involving 4554 children aged 6 to 12, researchers uncovered that children with greater dietary intake of vitamin C had a decreased likelihood of developing allergic rhinitis.

In a 2019 trial [5], 80 participants with allergic rhinitis and low vitamin D (14 ng/ml) participated. The treatment group received 50,000 IU vitamin D weekly for 8 weeks, along with antihistamines. Vitamin D levels rose from 14.0 ng/ml to 24.08 ng/ml, significantly improving rhinitis symptoms. [6]. Similar trials also support vitamin D’s role in relieving allergic rhinitis symptoms. [5][7].

Probiotics

Appropriate probiotic supplementation relieves allergic rhinitis symptoms, including hay fever, and regulates gut microbiota to improve rhinitis. A 2016 meta-analysis [8] encompassing 22 clinical trials found 17 studies reporting enhanced rhinitis symptoms with probiotics. Eight studies showed immune system inflammation marker improvements. Five studies focused on Lactobacillus paracasei, highlighting its efficacy in alleviating rhinitis. Despite trial variations, probiotics, especially Lactobacillus paracasei LP-33, consistently improve allergic rhinitis symptoms.

Summary

Based on recent research, allergic rhinitis is associated with immune reactions caused by imbalanced gut microbiota. Non-pharmacological methods for improvement include:

Reduce antibiotic usage.

Maintain a healthy diet with plenty of vegetables and fruits.

Increase vitamin C intake, monitor vitamin D levels, and supplement if deficient.

Consider targeted supplementation of beneficial probiotic strains to improve rhinitis symptoms.