Higher vitamin A levels were linked to better lung function in adults and children, with the benefit seen with vitamin D among adults as well, a study showed.
Vitamin A and Lung Function
Higher vitamin A levels correlated with significantly higher forced expiratory volume in 1 second (FEV1; β=2.5 in children and 4.7 in adults) and forced vital capacity (FVC; β=7.6 in children and 3.4 in adults), Michael McGeachie, PhD, of Brigham and Women’s Hospital in Boston, and colleagues reported in Thorax.
Children showed a lower ratio of FEV1/FVC with higher vitamin A (β=-3.9), whereas the relationship was positive for adults (β=2.5).
Impact of Vitamin D
The two age groups also differed on impact of vitamin D, which didn’t correlate with lung function measures in kids but had significantly positive associations with FEV1 (β=0.16) and FVC (β=0.18) among adults. This discrepancy in children may stem from insufficient statistical power to detect trends in vitamin D levels in our childhood cohort, the researchers noted, as only about half of the child cohort had these levels measured.
Both vitamins are versatile micronutrients involved in lung development, primarily through regulation of gene expression.
Biological Mechanisms
The researchers looked at the biological mechanisms behind the associations via gene expression, or what an accompanying editorial called “nutritional epigenetics.” Specifically, they examined how vitamin A and D levels influence regulators (miRNA) and markers of epigenetics (DNA methylation) and used mediation analyses to demonstrate that miRNAs and DNA methylation partially mediate the relationship between vitamin levels and lung function.
Reduced methylation of the IRF5 gene with higher vitamin levels was linked to improved lung function in children and adults. “IRF5 is a transcription factor that plays a critical role in regulating airway macrophage differentiation,” the editorialists noted.
Potential for Personalized Nutrition
The epigenetic findings also point to potential targets for personalized nutrition in asthma care, the researchers wrote, although the editorialists pointed to the failure of interventional studies to show a benefit of vitamin D supplementation on lung function in children and adults with asthma.
The associations with vitamin D might reflect residual confounding, as higher levels are often associated with healthier behaviors and overall better health that may independently influence lung function.
Study Limitations
The study utilized two asthma cohorts: 1,165 children ages 6-14 years (average 9.2 years) in the Genetic Epidemiology of Asthma in Costa Rica Study and 1,041 adults (average age 58.8 years) in the Omic Determinants of Longitudinal Lung Function in Asthma study of the Mass General Brigham Biobank. Limitations of the study were inability to determine causality, relative quantification of plasma vitamin A, lack of mRNA expression data, and absence of longitudinal data limiting conclusions about temporal effects.
Future work should address these gaps using absolute, repeated measures to clarify vitamin–lung function dynamics over time, McGeachie and colleagues wrote.
Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
Fuente: https://www.medpagetoday.com/pulmonology/asthma/121987
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