Vitamin A & D Deficiency in Children: Health Impacts & Testing
A Science-Backed Review of the Chinese Expert Consensus on Clinical Application of Vitamin A and Vitamin D in Children (2024)
Recent survey results indicate that the prevalence of vitamin A deficiency and marginal deficiency among preschool children in China remains high, with an increasing trend as children grow older. Among children aged 0 to 18, vitamin D deficiency and insufficiency are widespread, and a correlation exists between vitamin A and vitamin D deficiency. In response, the Child Health Care Branch of the Chinese Preventive Medicine Association convened experts to revise the "Chinese Expert Consensus on Clinical Application of Vitamin A and Vitamin D in Children" (originally published in 2021), aiming to provide reference guidance for the clinical application and deficiency prevention of vitamin A and vitamin D in Chinese children.
Health Impacts of Vitamin A and Vitamin D Deficiency in Children
Vitamin A is a fat-soluble vitamin essential for maintaining normal metabolism and physiological functions. It plays critical roles in sustaining dark vision, promoting epithelial cell regeneration, maintaining the integrity of skin and mucosal surfaces, supporting growth and development, enhancing immune function, maintaining reproductive function, and influencing hematopoiesis. Recent research has also revealed that vitamin A participates in renal injury repair and may exert anti-cancer effects.
01. Visual Impairment
Vitamin A deficiency leads to depleted visual pigments, impairing dark adaptation. Severe deficiency can cause night blindness; if progression continues, it may result in irreversible ocular diseases such as xerophthalmia, keratitis, and even blindness. During growth and development, when a child's vision is not yet fully mature, vitamin A deficiency can adversely affect visual development.
02. Compromised Immunity
Vitamin A deficiency causes epithelial damage, reduced antibody production, and impaired immune function. Children deficient in vitamin A are more susceptible to various pathogens, with increased risk of pneumonia, gastrointestinal diseases, and measles, thereby affecting healthy growth.
03. Growth Retardation
Vitamin A promotes childhood growth and development by enhancing early osteoblast differentiation and inhibiting bone mineralization. Deficiency can lead to abnormal bone development — including reduced bone density and increased fracture risk — as well as growth retardation, with slow gains in height and weight, and potentially developmental failure.
04. Skin Disorders
Vitamin A deficiency suppresses mucosal secretion, causing epithelial stratification and keratinization. This leads to skin conditions such as xerosis cutis and hyperkeratosis. In children, this manifests as rough skin and thickened keratin layers. Mucocutaneous lesions compromise the mucosal barrier, predisposing to infection.
05. Anemia
Vitamin A deficiency restricts hematopoietic gene expression, interferes with erythroid progenitor cell synthesis, and affects hepcidin expression, leading to anemia. Furthermore, vitamin A deficiency predisposes children to severe chronic infections, which further exacerbate anemia.
06. Neurobehavioral Development
Research demonstrates a close correlation between children's neurobehavioral development and vitamin A status. Among various neurobehavioral disorders, children with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and tic disorders exhibit lower vitamin A levels than healthy children. Following vitamin A supplementation, these children show noticeable improvements in social functioning.
The physiological functions of vitamin D encompass both endocrine and paracrine activities. Endocrine functions include intestinal calcium transport, bone metabolism, renal calcium reabsorption, and insulin secretion. Paracrine functions include inhibition of cell proliferation and immune regulation. Recent studies have found that vitamin D deficiency can also lead to decreased immunity in children, increasing the risk of allergic diseases and pulmonary conditions. It may even affect cardiovascular development and cause neurobehavioral abnormalities.
01. Skeletal Dysplasia
Vitamin D is a key nutrient for calcium and phosphorus absorption and bone development. Deficiency leads to inadequate skeletal mineralization in children, resulting in rickets, osteoporosis, and other bone development disorders.
02. Compromised Immunity
Vitamin D plays a role in multiple aspects of the immune system. Deficiency is closely associated with increased incidence of respiratory tract infections, intestinal infections, and skin infections in children. During infection, pathogens and inflammatory responses affect vitamin D metabolism, further lowering vitamin D levels. Deficiency is also linked to the development of autoimmune diseases.
03. Neuropsychiatric Symptoms
Vitamin D plays an important role in neuroimmune regulation, neurotrophic factor expression, and neurotransmission in the brain. Deficiency may therefore affect neurological functions associated with ADHD. Recent studies indicate that vitamin D deficiency increases the risk of cognitive impairment and impaired social-emotional development.
04. Allergic Diseases
Vitamin D deficiency may cause immune system imbalance, thereby increasing the risk of allergic diseases. Children with vitamin D deficiency are more prone to allergic rhinitis, asthma, and eczema.
05. Obesity and Metabolic Disorders
Vitamin D plays an important role in maintaining insulin secretion and insulin sensitivity. Deficiency may affect glucose regulation and increase diabetes risk. Vitamin D deficiency is closely associated with the onset, progression, and complications of type 1 diabetes.
06. Other Systemic Effects
Vitamin D participates in vascular endothelial function regulation and is important for maintaining normal blood pressure and cardiovascular health. Childhood vitamin D deficiency increases the risk of cardiovascular disease in adulthood. Additionally, vitamin D promotes fetal and neonatal lung development and maturation. Deficiency can lead to neonatal respiratory distress syndrome and bronchopulmonary dysplasia.
Vitamin Testing: Methods and Clinical Significance
Vitamin testing enables clinicians to more accurately assess vitamin status, comprehensively understand individual vitamin levels, and guide rational vitamin supplementation — thereby reducing the incidence of nutritional diseases. Furthermore, testing provides an important theoretical basis and evaluation standard for the clinical use of vitamin preparations.
Multiple methods are currently available for vitamin detection, including immunoassay, spectrophotometry, fluorometry, enzyme-linked immunosorbent assay (ELISA), microbiological assay, and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Among these, LC-MS/MS is recognized as the gold standard for vitamin detection due to its high sensitivity and high specificity.
| Method | Sensitivity | Specificity | Assessment |
|---|---|---|---|
| Immunoassay | Moderate | Moderate | Cross-reactivity possible; limited multiplexing |
| Spectrophotometry | Low | Low | Simple but prone to interference |
| Fluorometry | Moderate | Moderate | Limited to fluorescent analytes |
| ELISA | Moderate | Moderate | Widely available but cross-reactivity concerns |
| Microbiological Assay | Low | Moderate | Time-consuming; limited throughput |
| LC-MS/MS | High | High | Gold standard — simultaneous multi-analyte detection, no cross-reactivity |
The "Recommendations for Clinical Application of Liquid Chromatography-Mass Spectrometry" explicitly state that compared to immunoassay methods, LC-MS is more suitable for the qualitative and quantitative detection of vitamins.
VirtueDx QSight 420MD Triple Quadrupole Mass Spectrometry Platform
The VirtueDx QSight 420MD triple quadrupole mass spectrometry platform offers a comprehensive range of vitamin detection reagents, enabling precise measurement of children's vitamin levels and safeguarding healthy growth and development.
Vitamin A Deficiency Children · Vitamin D Deficiency Children · Pediatric Vitamin Supplementation · LC-MS/MS Vitamin Testing · Child Health Vitamins · Rickets · Night Blindness · Vitamin A D Consensus · Vitamin Testing Gold Standard · Vitamin D Immunity · Vitamin A Neurobehavioral Development · Clinical Mass Spectrometry · In Vitro Diagnostics · VirtueDx
