What does vitamin a do
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The Multifaceted Role of Vitamin A: Vision, Immunity, and Beyond
Vitamin A and Vision: Essential for Phototransduction
Vitamin A is crucial for vision, particularly in the process of phototransduction, where it plays a key role in converting light into electrical signals in the retina. The active form, 11-cis-retinal, is isomerized to all-trans-retinal during this process and then recycled back to 11-cis-retinal. This cycle is vital for maintaining visual function, and any disruption can lead to visual impairments and retinal diseases4.
Immune System Enhancement: Anti-Inflammatory and Regulatory Roles
Vitamin A is often referred to as an anti-inflammation vitamin due to its significant role in enhancing immune function. It is involved in the development and regulation of the immune system, influencing both cellular and humoral immune responses. Vitamin A supplementation has been shown to reduce morbidity and mortality from infectious diseases, particularly in children with acute measles or those from areas with endemic vitamin A deficiency1 3. It enhances antibody responses, increases lymphocyte proliferation, and helps maintain the integrity of mucosal surfaces, which are critical for preventing infections1 3.
Growth and Development: Crucial for Skin, Hair, and Lung Health
Vitamin A is essential for the growth and maintenance of healthy skin and hair. Its active metabolites, retinoic acid and retinal, regulate hair follicle stem cells and influence the hair cycle, wound healing, and melanocyte function. However, both deficiency and excess of vitamin A can have detrimental effects on skin and hair health8.
In preterm infants, vitamin A is necessary for normal lung growth and the integrity of respiratory tract epithelial cells. Supplementation in very low birth weight infants has been associated with a reduction in the risk of chronic lung disease and mortality, highlighting its importance in neonatal health5 9.
Metabolic Functions: Impact on Obesity and Diabetes
Vitamin A also plays a role in metabolic health, influencing the development of obesity and related diseases such as insulin resistance, type 2 diabetes, and cardiovascular disease. Retinoic acid, the active form of vitamin A, and proteins involved in its metabolism, such as retinol-binding protein 4 (RBP4) and aldehyde dehydrogenase 1A1 (ALDH1A1), have been linked to these metabolic disorders. These associations suggest that vitamin A and its related proteins may have both preventive and causative roles in metabolic diseases10.
Conclusion
Vitamin A is a vital micronutrient with diverse roles in the human body, from maintaining vision and enhancing immune function to supporting growth and development and influencing metabolic health. Its importance cannot be overstated, and both deficiency and excess can lead to significant health issues. Understanding the multifaceted roles of vitamin A can help in developing targeted interventions for various health conditions.
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Most relevant research papers on this topic
Role of Vitamin A in the Immune System
Vitamin A plays a crucial role in enhancing immune function and has shown therapeutic effects in treating various infectious diseases.
Literature Review
Rigorous Journal
Highly CitedVitamin A Update: Forms, Sources, Kinetics, Detection, Function, Deficiency, Therapeutic Use and Toxicity
Vitamin A plays a crucial role in multiple physiological functions, and its deficiency and metabolic fate can lead to potential pharmacological administration and toxicity.
Very Rigorous JournalHighly CitedVitamin A, immunity, and infection.
Vitamin A supplementation reduces severe morbidity and mortality from infectious diseases, with potential applications in therapy for some infectious diseases.
Highly CitedThe Role of Vitamin A in Retinal Diseases
Vitamin A plays a crucial role in retinal diseases, affecting visual phototransduction and potentially causing toxic chemical accumulation in the retina.
Vitamin A supplementation to prevent mortality and short- and long-term morbidity in very low birth weight infants.
Vitamin A supplementation may have a small benefit in reducing the risk of death or chronic lung disease in very low birth weight infants.
Meta-AnalysisVery Rigorous JournalHighly CitedVitamin A: too good to be bad?
Vitamin A is crucial for vision, cell growth, reproduction, and immunity, but excessive or deficient consumption can cause severe health consequences.
Adjuvanticity of Vitamin A
Vitamin A may act as an adjuvant by damaging lysosomal membranes, stimulating cell division, and potentially inducing immunity rather than paralysis.
Highly CitedVitamin A in Skin and Hair: An Update
Vitamin A, specifically retinoic acid, is essential for healthy skin and hair growth, but excessive intake can cause harm.
Very Rigorous JournalVitamin A supplementation to prevent mortality and short and long-term morbidity in very low birthweight infants.
Vitamin A supplementation in very low birthweight infants can reduce death and oxygen requirement, potentially improving long-term neurodevelopmental outcomes.
Meta-AnalysisHighly CitedVitamin A signaling and homeostasis in obesity, diabetes, and metabolic disorders.
Vitamin A and related proteins play a role in obesity development, diabetes, liver disease, and cardiovascular disease, with retinoic acid being the most significant factor.
Literature ReviewHighly Cited