From the Guidelines
Vitamin A deficiency is a significant public health problem that requires immediate attention and supplementation to prevent morbidity, mortality, and impaired quality of life, particularly in developing countries and high-risk populations. The condition occurs when the body lacks adequate vitamin A, an essential fat-soluble vitamin crucial for vision, immune function, and cellular growth 1.
Causes and Risk Factors
The deficiency can be caused by various factors, including malnutrition, liver disease, chronic alcohol consumption, liver transplantation, chronic kidney disease, short bowel syndrome, cystic fibrosis, coeliac disease, and chronic diarrhea 1. Obesity is also a risk factor, as retinol-binding protein (RBP) is produced in the liver and adipocytes, leading to a low retinol-RBP ratio 1.
Diagnosis and Treatment
Diagnosis is typically made through clinical signs, serum retinol levels below 0.7 μmol/L, or abnormal dark adaptation testing 1. Treatment involves immediate supplementation with vitamin A, typically administered as retinyl palmitate or retinol. According to the most recent guidelines, oral supplementation with vitamin A, 10,000–25,000 IU d−1 for 1–2 weeks, is recommended for clinical improvement in adults 1. Higher doses, including intramuscular injections, may be needed if the person is experiencing night blindness 1.
Prevention Strategies
Prevention strategies include dietary diversification, food fortification, and supplementation programs in high-risk populations 1. Incorporating foods rich in vitamin A, such as liver, fish oils, egg yolks, dairy products, and orange or yellow fruits and vegetables, is essential for long-term prevention.
Key Considerations
It is crucial to monitor vitamin A levels regularly, especially in patients with chronic kidney disease, as high retinol serum levels can be temporary and lead to a deficiency if liver stores become depleted 1. In cases of very low serum retinol levels, intravenous administration of retinol palmitate may be proposed, but more research is needed to support this recommendation 1.
From the Research
Definition and Prevalence of Vitamin A Deficiency
- Vitamin A deficiency is a major public health problem in low- and middle-income countries, affecting 190 million children under five years of age 2.
- It is the leading cause of preventable severe visual impairment and blindness, and a significant contributor to severe infections and death, particularly from diarrhea and measles 3.
Clinical Manifestations
- Clinical manifestations of vitamin A deficiency include night blindness, conjunctival xerosis, Bitot spots, and corneal xerosis, which can lead to corneal ulceration and liquefactive necrosis (keratomalacia) 4.
- Corneal perforation is a severe complication of vitamin A deficiency, which can be caused by various etiologies such as primary biliary cirrhosis, malnutrition, and malabsorption syndrome 5.
- Vitamin A deficiency can also cause alterations in the anterior segment of the eye, including corneal manifestations such as reactive ulceration and spontaneous perforation 6.
Diagnosis and Treatment
- Laboratory indicators of vitamin A deficiency include conjunctival impression cytology and serum retinol concentrations 4.
- The World Health Organization recommends the use of two biological markers to characterize vitamin A deficiency in a given population 4.
- Treatment of vitamin A deficiency involves vitamin A supplementation, which can be administered orally in doses of 200,000 IU, repeated after 24 hours 4.
- Vitamin A substitution can improve symptoms and ocular surface integrity, and should be initiated as early as possible to prevent serious disease progression 5.
Prevention and Control
- Prevention and control of vitamin A deficiency can be achieved through a combination of strategies, including promotion of breast-feeding, control of infections, dietary diversification, food fortification, and supplementation 3.
- Vitamin A supplementation has been shown to reduce the risk of all-cause mortality, diarrhea, and measles in children aged 6-59 months 2.
- Food fortification and dietary diversification are also effective strategies for preventing vitamin A deficiency, particularly in populations with limited access to healthcare 3.