Inflammatory Diets Increase Risk of Allergic Rhinitis

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A positive association was found between diets high in inflammatory foods and allergic rhinitis (AR)—a common chronic inflammatory condition—according to research published in Frontiers in Nutrition. Investigators encourage people to consume more anti-inflammatory nutrients and limit pro-inflammatory nutrients as a preventative measure.

AR, a condition that affects approximately 20 – 40% of the global population, significantly impacts a patient’s quality of life due to difficulties sleeping, learning and performing daily activities. Common symptoms include sneezing, congestion, itching, rhinorrhea and itchy red eyes.

“Considering the significant role of lifestyle factors in modulating inflammatory responses, it is essential to investigate how modifiable risk factors such as unhealthy dietary practices, lack of physical activity, obesity and chronic stress can exacerbate the progression of AR,” wrote a group of investigators from Shanxi Medical University, in China. “Among these modifiable factors, diet emerges as a significant adjustable element, offering a potential avenue for the prevention and management of AR through lifestyle modifications.”

Diet may also play a significant role in lowering the risk of a number of allergic diseases, with one study demonstrating improvements in airway reactivity among a cohort of children who increased their fruit and vegetable intake, and another study concluding higher levels of omega-3 fatty acids reduced the risk of developing atopic dermatitis.

However, the research is limited regarding the association between the Dietary Inflammatory Index (DII) and the risk of AR. This relationship was explored using a sample of adults from North China. The case-control study recruited 166 patients with AR and 166 age- and gender-matched controls. Their dietary intake was evaluated using a food frequency questionnaire, called the Chinese Food Frequency Questionnaire (FFQ), and energy-adjusted DII (E-DII) scores were determined based on the quantity of foods with inflammatory or anti-inflammatory characteristics.

Subjects reported how often they consumed a variety of foods, including meat, eggs, vegetables, fruits, legumes, dairy and oil, as well as their average portion sizes. Based on this information, investigators were able to calculate a person’s daily intake.

In addition to dietary information, the team collected data on demographics, such as age, gender, occupation, education, marital status, exercise habits, smoking and alcohol consumption, and body mass index (BMI). In the AR group, information about the type, severity and duration of the disease were included.

Investigators categorized E-DII scores into 3 tertiles: T1 (≤ -1.48), T2 (-1.48 and -.36) and T3 (> -.36). T1 represented an anti-inflammatory diet and T3 was pro-inflammatory. No significant differences in variables including age, gender, occupation, education, and smoking status were observed among the tertiles, indicating E-DII scores were not linked to any sociodemographic factors.

However, investigators observed a link between E-DII scores and AR risk, with patients consuming a more inflammatory diet exhibiting a greater risk of developing the disease. Patients with AR ate more total fat compared with controls, while their intake of protein, fiber, carbohydrates, and vitamins and minerals—including vitamin A, vitamin B, vitamin E, vitamin C, iron, zinc and magnesium—were lower compared with the control group. A higher intake of fat and lower consumption of protein, carbohydrates, fiber, and vitamins and minerals were associated with higher E-DII scores for patients with AR.

Further, subjects with the highest E-DII scores were more likely to develop AR compared with participants with the lowest scores. The odds of developing AR rose with each increment in E-DII score, indicating a pro-inflammatory diet raises the risk of AR.

“By adopting a comprehensive approach that considers individual, cultural, and regional factors, future studies can enhance our understanding of the intricate relationship between diet and AR,” investigators concluded. “This knowledge can ultimately guide the formulation of effective preventive measures and personalized dietary interventions, improving the quality of life for those affected by AR.”