Dietary olive oil enhances the oral tolerance of the food allergen ovalbumin in mice by regulating intestinal microecological homeostasis

Abstract

Increasing evidence indicates that intestinal microecological imbalances are strongly associated with food allergen intolerance. This study investigated the effect of olive oil on food allergy susceptibility and intestinal microecology based on an ovalbumin (OVA)‐sensitized mouse model. The results indicated that the allergic symptoms of sensitized mice were alleviated when they were supplemented with olive oil at 1–3 g/kg per day for 7 weeks. Intestinal epithelium observation showed repaired ileum villi and upregulated tight junction (TJ) protein expression. Furthermore, the levels of the cytokines (e.g., IL‐10) secreted by regulatory T cells were increased, whereas T helper 2 (Th2) cell‐associated factors were decreased in lamina propria. Furthermore, 16S rRNA sequencing indicated reduced Burkholderiaceae and increased Clostridiaceae in the intestinal microflora. The results suggest that an olive oil‐enriched diet may effectively prevent food allergies by regulating the intestinal microecological balance. Practical applications Recent studies emphasized that intestinal ecological imbalance, including intestinal immunity and microflora structure, plays an important role in affecting the occurrence and development of food allergy. The present results implied that olive oil, one of the main components of the Mediterranean diet, can effectively ameliorate the symptoms of OVA‐induced food allergy by regulating intestinal microecological homeostasis. Therefore, dietary supplementation with olive oil may be an effective strategy for preventing food allergies.

The Effect of Dietary Components of the Mediterranean Diet on Food Allergies: A Systematic Review

“…All the animal studies indicated a positive relationship between the food components of the MD and food allergies. The food components used were olive oil and enriched polyphenols [21][22][23][24].…”

“…All four animal studies used the ovalbumine (OVA)-sensitized BALB/c mouse model as their food allergy model. The two studies by Ma et al (2022Ma et al ( , 2023 fed their animals olive oil prior to sensitization. In the studies by Singh et al and Zuercher et al [23,24], they fed their mice with enriched polyphenols (either epicatechin or flavonol).…”

“…Two of the animal studies investigated the effect of olive oil on food allergies and demonstrated a beneficial effect [21,22]. This was demonstrated by a does-dependent inhibition of allergen-specific antibodies (IgG and IgE) as well as a decrease in the expression of TGF-β [21].…”

“…Two of the animal studies investigated the effect of olive oil on food allergies and demonstrated a beneficial effect [21,22]. This was demonstrated by a does-dependent inhibition of allergen-specific antibodies (IgG and IgE) as well as a decrease in the expression of TGF-β [21]. The second study also found a decrease in clinical symptoms of allergy (dose-dependent) as well a a decrease in IgE, mouse mast cell protease (mMCP)-1, and TNF-α levels in the olive oil group (p < 0.01).…”

The Role of Diet and Nutrition in Allergic Diseases

“…Recently, it was shown that olive oil confers protection again food allergies by improving gut mucosal barrier integrity [79]. Olive oil also enhances oral tolerance to dietary allergens by decreasing serum antigenspecific IgE, antigen-specific IgG, and histamine [80]. Increased IL-10 and decreased IL-4 associated with olive oil feeding indicate that Tregs and Bregs are induced.…”