A Short-Term High-Sugar Diet Induces Glucose Intolerance, Visceral Adipose Tissue Inflammation, and Exacerbates Experimental Allergic Asthma.

BACKGROUND

Diets composed of various components have been shown to influence inflammatory diseases such as asthma. While most studies have focused on fiber-rich diets to investigate their effects on the immune system and, consequently, on asthma, little is known about the impact of sugar-rich diets, particularly when such diets are consumed over short periods of time.

METHODS

To investigate the short-term effects of a sugar-rich diet on allergic airway inflammation, A/J mice were fed either a standard diet or a sugar-enriched diet and subsequently sensitized and challenged with ovalbumin or PBS. Airway inflammation was assessed by bronchoalveolar lavage (BAL) cell analysis, including eosinophil counts and cytokine levels (IL-4, TNF-α, IL-33), and by lung histology (H&E for inflammatory infiltrate and PAS for mucus). Serum IgE levels were also measured. In addition, glucose tolerance, visceral and subcutaneous adipose tissue mass, and inflammatory markers in visceral adipose tissue were evaluated.

RESULTS

Short-term consumption of a sugar-rich diet induced glucose intolerance and expansion of adipose tissue, particularly visceral fat, independent of ovalbumin sensitization. Gonadal adipose tissue analysis revealed a shift toward M1 macrophage polarization, characterized by elevated TNF-α, IL-6, and IL-1β, increased leptin levels, and reduced adiponectin. In OVA-sensitized mice, the sugar-rich diet significantly exacerbated eosinophil infiltration in BAL, increased IL-4, TNF-α, and IL-33, and enhanced PAS-positive mucus accumulation and inflammatory infiltrates in the lung. Moreover, total serum IgE was significantly higher in allergic mice fed the sugar-rich diet compared with allergic mice on the standard diet. Importantly, in non-sensitized mice fed the sugar-rich diet, no pulmonary inflammation was detected by BAL, demonstrating that HSD alone does not induce asthma but amplifies allergic responses when sensitization is present.

CONCLUSIONS

Our findings demonstrate that short-term consumption of a sugar-rich diet is sufficient to exacerbate, but not initiate, allergic pulmonary inflammation. From a translational perspective, reducing dietary sugar intake may represent a valuable adjuvant strategy in the management of allergic asthma.