How is the "Relationship between Dietary Intake of Vitamin A and Lung Function" encoded by the genome?
Vitamin A is a versatile vitamin involved in multiple biological processes, including lung development. As an essential micronutrient, vitamin A must be obtained from the diet either as preformed vitamin A, found in animal foods such as cheese, eggs, and liver/liver products, or as pro-vitamin A, found in plant foods such as spinach, carrots, and red peppers. For ultimate lung function, getting enough vitamin A as young adult is optimal for growth, and can help prevent future issues.
Animal data suggest that retinoic acid, what is metabolized of vitamin A, plays a crucial role early in life in lung development, maintenance, and regeneration. Previous studies also suggest a key role in airway development. However, in humans, the relationship between dietary vitamin A and respiratory outcomes is unclear, especially in ranges of intake that do not cause severe hypovitaminosis. Epidemiological data over time is scarce on the relationship between dietary intake of vitamin A and respiratory outcomes in childhood.
To clarify the relationship between dietary intake of vitamin A and respiratory outcomes in childhood, researchers explored the relationships of provitamin A intake at 7 years of age with lung function in the Avon Longitudinal Study of Parents and Children (ALSPAC). In the ALSPAC, dietary intakes of preformed vitamin A and β-carotene equivalents were estimated by food frequency questionnaire at 7 years of age. While a breathing/lung function test was measured at 15.5 years. As for rs12708369 in the nuclear receptor corepressor 2 (NCOR2) gene, vitamin A intake was positively associated with lung performance in carriers of the C allele, but negatively associated in those homozygous for the T allele. A similar pattern of associations was observed between carotene intake and airflow in those homozygous for the C and T allele respectively. The positive associations found in carriers of the C allele in this study, the variant associated with higher exhale capacity in children, suggest that vitamin A might also have a role in lung growth through the regulation of fibroblasts. Lastly, there was no evidence of interaction with maternal atopy, paternal atopy, or maternal smoking with lung function found in this study.
Strengths of this study include the population-based prospective, large amounts of data, and rich information on diet and other factors.. One of the breathing assessments of lung function led to a better assessment of airway growth by eliminating reversible airflow limitation. If you would like to know more about this research, you can read the study here:
https://pubmed.ncbi.nlm.nih.gov/33795317/
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