In a recent study published in the journal Frontiers in Nutrition, researchers used Mendelian Randomization (MR) to investigate whether regular nutrient consumption and serum mineral, vitamin, and antioxidant levels are causally associated with childhood asthma (CA) risk.
Study: Dietary intake, antioxidants, minerals and vitamins in relation to childhood asthma: a Mendelian randomization study. Image Credit: Ilike / Shutterstock
Background
Asthma, a common chronic respiratory illness, especially among children, is characterized by airway inflammation, wheezing, and bronchial reactivity. It is a growing global issue, with the primary risk factors being air pollutants and cigarette particle exposure. However, diet can mediate childhood asthma development risk. Diversified diets can lower childhood asthma risk by restoring the gut microbiome. Understanding the causal association between nutrition and allergies is crucial for childhood asthma prevention and management. Limited evidence exists on the associations between regular consumption of vitamins, minerals, and nutrients and serological antioxidant levels.
About the study
In the present MR analysis, researchers determined causal associations between protein, fat, carbohydrate, and sugar intake, the serological levels of vitamins, minerals, and antioxidants, and childhood asthma.
The researchers selected regular dietary intake-related factors, including proteins, carbohydrates, sugars, and fats, and serological antioxidant concentrations (β-carotene, lycopene, and uric acid), minerals (copper, calcium, zinc, selenium, phosphorus, magnesium, and iron), and vitamins (vitamins A, B6, B12, C, D, E, and folate). They used these parameters as instrumental variables (IVs). They obtained genetic information concerning childhood asthma from the publicly accessible genome-wide association study (GWAS) Catalog and FinnGen databases.
The team used the Inverse Variance Weighting (IVW) approach for data analysis. When at least three valid instrumental variables (IVs) were available, the researchers performed sensitivity analyses using three MR approaches to investigate potential biases generated by inefficient IVs, including weighted-median (WM), MR-Egger regressions (MRE), and MR Pleiotropy Residual Sum and Outlier (MR-PRESSO).
The researchers determined odds ratios and conducted independent tests, applying Benjamin-Hochberg corrections for false discovery rates (FDR). Individual instrumental variables, such as vitamin B6 and selenium, were used to derive their effect estimates using the Wald Ratio (WR). The team used fixed-effects models for meta-analysis to facilitate an overall risk assessment and prediction of childhood asthma.
Results and discussion
The analysis showed inverse associations between sugar intake (odds ratio, 0.7) and childhood asthma risk, whereas magnesium (odds ratio, 1.6), fat (odds ratio, 1.4), and D vitamin (odds ratio, 1.1) intakes were positively related to elevated CA risks. Meta-analysis confirmed the statistical significance of the associations, aligning with the findings reported in a few databases. Sensitivity analyses yielded similar results. The findings indicate that increasing complex carbohydrate consumption in the Mediterranean diet (MD) pattern may reduce childhood asthma risk. Compared to previous studies, the current study demonstrates a paradox in the effect of sugar consumption on CA levels. Nonetheless, other associational findings are consistent with earlier studies.
The current study's researchers discovered significant connections between phosphorus and zinc in one database. In contrast, magnesium, while statistically significant in the meta-analysis results of the present study, did not reveal a consistent trend in three additional datasets. Although the current investigation found a positive link between blood magnesium and the risk of pediatric asthma, the researchers could not demonstrate precise causal correlations between serum copper, phosphorus, and asthma risk. However, the findings of the observational study primarily agree with those of the present study.
Studies associate fructose in fruit juices and drinks with metabolic abnormalities and asthma-like symptoms in non-obese mice. A diet heavy in fat and protein may raise the risk of pediatric asthma by increasing obesity and activating inflammatory pathways. Antioxidants such as vitamins E and C, carotenoids, ubiquinone, flavonoids, and selenium neutralize free radicals and minimize oxidative damage, which promotes airway inflammation. Although the precise link between antioxidants and pediatric asthma is unclear, they are essential for prevention and therapy. Vitamin D supplementation may lessen the incidence of newborn asthma and acute asthma exacerbations in individuals with low levels.
Based on the study findings, increasing sugar intake while decreasing dietary fat content may lessen the incidence of childhood asthma. Elevated magnesium and vitamin D levels raised the risk. However, these findings derive from Mendelian randomization research, and additional inquiry is needed to verify these correlations. The analysis uses various datasets to establish the connection between dietary consumption, micronutrients, and childhood asthma; nevertheless, limitations include demographic selection, IV explanatory power, and a lack of research on intake levels. More study is needed to improve understanding of the biological pathways and improve instrumental variable selection.
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