Associations between childhood asthma and dietary intake, minerals, vitamins, antioxidants

Investigators of a recent study published in Frontiers identified a causal relationship between childhood asthma (CA) and the dietary intake of sugars and fats, along with the magnesium and vitamin D levels in serum.

The chronic respiratory disease has an increasing global incidence, with an estimated 300 million people in the affected population, including over 25 million individuals in the United States, of which approximately 9 million children are affected. Though major risk factors for CA include air pollution and exposure to cigarette particles, dietary roles can be a factor in the development and occurrence of CA.

The investigative team, led by Liang Lou of the School of TCM Health Care, Leshan Vocational of Technical College, Leshan, Sicuan Province, China, noted that there is currently a limited amount of evidence assessing risk association between daily dietary intake, antioxidants, minerals, and vitamins with CA. Exploring and understanding these casual relationships with CA “holds significant implications for the prevention and treatment of this condition,” wrote the team.

The study used Mendelian Randomization (MR) methodology to investigate associations between daily dietary intake, serum antioxidants, minerals, and the circulating levels of serum vitamins with CA. This method uses genetic variants as instrumental variables (IVs) to substitute for correlated risk factors, assessing casual relationships between exposure factors and outcomes.

The investigators selected factors related to daily dietary intake including:

- Carbohydrates

- Proteins

- Fats

- Sugars

- Serum antioxidant levels (lycopene, uric acid, and β-carotene)

- Minerals (calcium, copper, selenium, zinc, iron, phosphorus, and magnesium)

- Vitamins (vitamin A, vitamin B6, folate, vitamin B12, vitamin C, vitamin D, and vitamin E)

Evaluation metrics employed included odds ratios (OR) and corresponding 95% confidence intervals (CI), while statistical significance was asserted when P < 0.05.

The investigative team used publicly available genome-wide association study (GWAS) data from the FinnGen and GWAS Catalog databases for various exposure-related MR analysis. The team conducted a meta-analysis of MR results from different databases, that provided “a comprehensive assessment of the associations between each exposure and risk.”

After MR analysis, the investigative team observed that sugar intake was inversely correlated with CA risk (OR: 0.71, 95% CI: 0.55-0.91 [P: 0.01]). The following were positively associated with an increased risk of CA:

- Intake of serum circulating magnesium levels (OR: 1.63, 95% CI: 1.06–2.53, [P: 0.03])

- Fats (OR: 1.44, 95% CI: 1.06–1.95, [P: 0.02])

- Serum vitamin D levels (OR: 1.14, 95% CI: 1.04–1.25, [P: 0.02])

The primary findings suggest that an increase in sugar intake paired with a decrease in dietary fat content could be associated with a reduced risk of CA. MR analysis demonstrated a significant correlation between elevated levels of serum circulating magnesium and serum vitamin D with increased risk of CA.

The study authors noted these results are the product of MR analysis and could require further investigation for validation. Further investigation could also lead to additional insight to the potential mechanisms linking dietary intake and trace elements with CA risk.

Overall, the study provided “robust support for the association between dietary intake, micronutrients, and CA through the integration of multiple databases,” wrote the investigators, who again noted, “Nevertheless, inherent limitations, such as population selection and the explanatory power of IVs, and the lack of research on intake levels. These limitations underscore the need for further research.”

Reference:

Luo L, Chen G, Zhou Y, Xiang Y and Peng J. Dietary intake, antioxidants, minerals and vitamins in relation to childhood asthma: a Mendelian randomization study. Front. Nutr. 11:1401881. doi:10.3389/fnut.2024.1401881