Summary:
Asthma is a common condition affecting the airways and is a major cause of preventable illness and death worldwide. In children and adolescents, poorly controlled asthma can impair lung development, and increase the risk of serious respiratory complications. Given its high prevalence, prevention strategies that address modifiable risk factors are a public health priority. While factors such as air pollution, allergens, and viral infections are well established, diet is one of the most modifiable influences. Carbohydrates are a major component of the diet and differ widely in their structure and health effects. They include added sugars such as those in honey, syrups, and fruit juices, sugars that are naturally found within whole foods, refined grains, whole grains, and dietary fiber. These carbohydrate subtypes may influence asthma risk through inflammatory and immune pathways. Diets high in added sugars and refined grains have been linked to increased inflammation and oxidative stress, whereas fiber, whole grains, and sugars found naturally in foods may have protective effects by supporting gut microbiome function and regulating immune responses. This study, a systematic review and meta-analysis, examined associations between multiple carbohydrate subtypes and the risk of asthma and wheeze. A total of 94 studies were included. Higher intake of dietary fiber, sugars found naturally in foods, and whole grain-rich foods was associated with a lower risk of asthma and wheeze. In contrast, consumption of added sugar-rich foods was associated with an increased risk of asthma. Overall, this study provides evidence that carbohydrate quality is relevant to asthma risk. Diets lower in added sugars and higher in fiber, sugars found naturally in foods, and whole grains may support asthma prevention and should be considered in population-level dietary recommendations aimed at improving respiratory health.
Abstract:
Background: Serving as the predominant energy substrate, dietary carbohydrate consumption patterns significantly influence human health. However, the association between carbohydrate intake and asthma risk remains unclear. This study aims to systematically review and meta-analyze existing evidence on associations between various carbohydrate types (including free sugars [FS], non-free sugars [NFS], refined grains [RG], whole grains [WG], and dietary fiber [DF]) and risk of asthma. Methods: From inception to May 2025, we systematically searched major databases (PubMed, Embase, Web of Science, and Cochrane Library) for epidemiological research on the associations between varied dietary carbohydrate types and risk of asthma or wheeze. Random-effect models were employed to calculate pooled odds ratios (pORs) with 95% confidence intervals (CIs). The I-squared (I2) statistic was used to assess heterogeneity. Results: Ninety-four investigations met inclusion criteria (26 cohort, 8 case–control, 60 cross-sectional). Intake of DF (asthma: pOR = 0.879, 95% CI: 0.781–0.989; wheeze: pOR = 0.844, 95% CI: 0.737–0.967), NFS (asthma: pOR = 0.922, 95% CI: 0.870–0.976; wheeze: pOR = 0.813, 95% CI: 0.745–0.887) and WG-rich foods (asthma: pOR = 0.851, 95% CI: 0.749–0.966) was associated with lower risks of asthma and wheeze. In contrast, consumption of FS-rich foods was associated with increased asthma risk (pOR = 1.176, 95% CI: 1.093–1.265). Despite significant heterogeneity (I2 = 53.1%–82.5%, all P < 0.05), sensitivity analyses (using trim-and-fill and leave-one-out methods) validated the stability of the findings. Conclusions: This study underscores the importance of promoting high-quality carbohydrate intake (characterized by low FS and high NFS, DF, and WG), to support asthma prevention at the population level.
Article Publication Date: 21/11/2025
DOI: 10.1186/s12937-025-01233-2
