High Sugar Intake to Lower Childhood Asthma Risk, While Fat, Magnesium, and Vitamin D Increase It

In a recent study published in the journal Frontiers in Nutrition, researchers used Mendelian Randomization (MR) to investigate the causal associations between regular nutrient consumption, serum mineral, vitamin, and antioxidant levels, and childhood asthma (CA) risk.

Background Asthma is a common chronic respiratory illness, especially among children, characterized by airway inflammation, wheezing, and bronchial reactivity. It is a growing global issue, primarily driven by air pollutants and cigarette smoke exposure. Diet can influence the development risk of childhood asthma, with diversified diets potentially reducing this risk by restoring the gut microbiome. Understanding the causal links between nutrition and allergies is essential for preventing and managing childhood asthma. However, limited evidence exists on the associations between regular consumption of vitamins, minerals, and nutrients and serological antioxidant levels.

About the Study In this MR analysis, researchers determined causal associations between the intake of proteins, fats, carbohydrates, and sugars, as well as serum levels of vitamins, minerals, and antioxidants, and the risk of childhood asthma.

The study considered dietary intake-related factors such as proteins, carbohydrates, sugars, and fats, and serological concentrations of antioxidants (β-carotene, lycopene, and uric acid), minerals (copper, calcium, zinc, selenium, phosphorus, magnesium, and iron), and vitamins (A, B6, B12, C, D, E, and folate). These factors were used as instrumental variables (IVs). Genetic information on childhood asthma was obtained from the genome-wide association study (GWAS) Catalog and FinnGen databases.

Data analysis was conducted using the Inverse Variance Weighting (IVW) approach. Sensitivity analyses using weighted-median (WM), MR-Egger regressions (MRE), and MR Pleiotropy Residual Sum and Outlier (MR-PRESSO) were performed to address potential biases from inefficient IVs. Odds ratios were determined, and independent tests were conducted with Benjamin-Hochberg corrections for false discovery rates (FDR). The Wald Ratio (WR) was used to derive effect estimates for individual instrumental variables. A fixed-effects model was employed for meta-analysis to assess and predict childhood asthma risk.

Results and Discussion The analysis showed inverse associations between sugar intake (odds ratio, 0.7) and childhood asthma risk, while magnesium (odds ratio, 1.6), fat (odds ratio, 1.4), and vitamin D (odds ratio, 1.1) intakes were positively related to increased CA risk. The meta-analysis confirmed the statistical significance of these associations, which aligned with findings from several databases. Sensitivity analyses yielded similar results. These findings suggest that increasing complex carbohydrate consumption, as seen in the Mediterranean diet (MD), may reduce childhood asthma risk. The study revealed a paradoxical effect of sugar consumption on CA risk, contrary to previous studies, but other findings were consistent with earlier research.

The study also discovered significant associations between phosphorus and zinc in one database. However, while magnesium showed statistical significance in the meta-analysis, it did not display a consistent trend across three additional datasets. Although a positive link between blood magnesium and pediatric asthma risk was found, precise causal correlations between serum copper, phosphorus, and asthma risk could not be established. The observational study’s findings were primarily in agreement with the present study.

Previous studies have linked fructose in fruit juices and drinks with metabolic abnormalities and asthma-like symptoms in non-obese mice. High-fat and high-protein diets may increase pediatric asthma risk by promoting obesity and activating inflammatory pathways. Antioxidants such as vitamins E and C, carotenoids, ubiquinone, flavonoids, and selenium can neutralize free radicals and reduce oxidative damage, which promotes airway inflammation. While the exact link between antioxidants and pediatric asthma is unclear, they are considered important for prevention and therapy. Vitamin D supplementation may reduce the incidence of newborn asthma and acute asthma exacerbations in individuals with low levels.

Conclusions The study suggests that increasing sugar intake while reducing dietary fat content may lower childhood asthma incidence. Elevated levels of magnesium and vitamin D were associated with increased risk. These findings, derived from Mendelian randomization research, warrant further investigation to confirm these correlations. The study utilized various datasets to explore the relationship between dietary consumption, micronutrients, and childhood asthma, but limitations included demographic selection, IV explanatory power, and a lack of research on intake levels. Further research is needed to improve understanding of the biological pathways and enhance instrumental variable selection.