Vitamin A is an essential fat-soluble vitamin for various physiological processes, including vision, immune function, growth and development, and reproduction. Vitamin A deficiency (VAD) is a significant public health problem in many developing countries, particularly sub-Saharan Africa and South Asia.
VAD can result from inadequate dietary intake of vitamin A or impaired absorption and utilization of the vitamin. It is most common in populations that rely heavily on a limited number of staple foods that are low in vitamin A, such as rice, maize, and cassava. Individuals with medical conditions, such as inflammatory bowel disease or cystic fibrosis, may also be at increased risk for VAD due to impaired absorption of dietary fats.
The early stages of VAD may be asymptomatic or manifest as dryness and thickening of the skin and mucous membranes, including the eyes. As VAD progresses, it can lead to night blindness, a condition in which a person has difficulty seeing in low light or darkness. In severe cases, VAD can cause corneal damage, leading to blindness.
VAD is a significant public health concern because it can increase the risk of infectious diseases, particularly children. Vitamin A is necessary for maintaining the integrity of mucous membranes, which are the body’s first line of defense against pathogens. VAD can also impair immune function, making individuals more susceptible to infections.
Prevention and treatment of VAD typically involve increasing dietary intake of vitamin A-rich foods, such as liver, sweet potatoes, carrots, spinach, and mangoes. In some cases, vitamin A supplements may be recommended.
Epidemiology
Vitamin A deficiency is a significant public health problem, particularly in developing countries. According to the World Health Organization (WHO), it is estimated that approximately 250 million preschool-age children are affected by vitamin A deficiency worldwide.
The epidemiology of vitamin A deficiency is complex and multifactorial. Several factors contribute to the prevalence of this deficiency, including inadequate dietary intake, poor absorption of vitamin A, and increased vitamin A requirements due to infections, particularly measles.
Populations most affected by vitamin A deficiency are those living in poverty, with limited access to food and a diet deficient in vitamin A-rich foods such as fruits, vegetables, and animal products. Vitamin A deficiency is also more common in regions with limited access to healthcare, sanitation, and education, as well as areas with high rates of infectious diseases.
Anatomy
Pathophysiology
Vitamin A deficiency (VAD) results from inadequate dietary intake of vitamin A or impaired absorption and utilization of the vitamin. Vitamin A is required for various physiological processes, including vision, immune function, growth and development, and reproduction. Vitamin A is necessary for maintaining the integrity of mucous membranes, which are the body’s first line of defense against pathogens. VAD can also impair immune function, making individuals more susceptible to infections. VAD can lead to a variety of pathophysiological changes:
One of the earliest manifestations of VAD is the development of keratinizing metaplasia in the respiratory, gastrointestinal, and urogenital tracts, which can thicken and dry the epithelial surfaces. VAD can also lead to changes in the structure and function of the skin, including impaired sebum production, increased susceptibility to infection, and impaired wound healing.
VAD can profoundly affect vision, particularly in low-light conditions. VAD can lead to the development of night blindness, which is a condition in which a person has difficulty seeing in low light or darkness. As VAD progresses, it can lead to corneal damage, resulting in permanent blindness.
In addition, VAD can lead to immune dysfunction, increasing the risk of infections. Vitamin A is necessary for the differentiation and maintenance of epithelial cells, and VAD can lead to impaired immune function and increased susceptibility to infection.
Etiology
Vitamin A deficiency (VAD) can occur due to various factors, including:
• Inadequate dietary intake: Vitamin A is primarily found in animal-based foods, such as liver, eggs, dairy products, and fatty fish. Plant-based foods such as dark leafy greens, carrots, and sweet potatoes also contain vitamin A, but in the form of carotenoids, which need to be converted to retinol (the active form of vitamin A) by the body. In populations with limited access to a diverse range of foods, particularly those who rely heavily on a limited number of staple foods, VAD can occur due to inadequate dietary intake of vitamin A.
• Malabsorption: Certain medical conditions such as celiac disease, Crohn’s disease, cystic fibrosis, and pancreatic insufficiency can impair the body’s ability to absorb fat and fat-soluble vitamins such as vitamin A. This can lead to VAD, even in individuals who consume adequate amounts of vitamin A.
• Increased demand: Pregnant and breastfeeding women have an increased demand for vitamin A, which is necessary for fetal development and milk production. Infants and young children also have an increased demand for vitamin A, which is necessary for growth and development. VAD can occur in populations with limited access to a diverse range of foods due to increased demand for vitamin A during these life stages.
• Alcoholism: Chronic alcohol consumption can impair the body’s ability to store and utilize vitamin A, leading to VAD.
• Medications: Certain medications, such as cholestyramine (used to lower cholesterol) and mineral oil (used as a laxative), can interfere with the absorption of fat and fat-soluble vitamins, including vitamin A.
• Zinc deficiency: Zinc is necessary for converting provitamin A carotenoids to retinol. In populations with zinc deficiency, VAD can occur even if dietary intake of vitamin A is adequate.
Genetics
Prognostic Factors
• Age: Children under five are at the highest risk of developing vitamin A deficiency and are more likely to suffer from severe symptoms.
• Malnutrition: Malnourished individuals, especially those who do not consume a balanced diet with adequate vitamin A, are at a higher risk of developing VAD.
• Poverty: People living in poverty, especially in developing countries, are more likely to suffer from VAD due to limited access to nutrient-rich foods and supplements.
• Infections: Certain infections, such as measles and diarrhea, can reduce the body’s ability to absorb vitamin A and increase the risk of developing VAD.
• Alcoholism: Excessive alcohol consumption can impair the liver’s ability to store and release vitamin A, leading to a deficiency.
• Chronic diseases: Individuals with chronic diseases such as cystic fibrosis, Crohn’s disease, and liver disease are at a higher risk of developing VAD due to impaired absorption or storage of vitamin A.
• Pregnancy and lactation: Pregnant and lactating women have increased requirements for vitamin A, and a deficiency can have severe consequences for both the mother and the child.
Clinical History
• Night blindness: This is one of the earliest and most common symptoms of VAD. The individual has difficulty seeing in low-light conditions, especially at night.
• Dry eyes: VAD can cause dryness of the eyes, leading to eye inflammation and infections.
• Bitot’s spots: These are small, white, foamy patches that appear on the conjunctiva (the membrane that covers the white part of the eye) in severe cases of VAD.
• Corneal ulcers: In advanced cases of VAD, the cornea (the transparent front part of the eye) can become dry and damaged, forming ulcers and scarring.
• Xerophthalmia: This is a term used to describe a group of eye conditions caused by VAD. It includes night blindness, Bitot’s spots, dry eyes, and corneal ulcers.
• Skin changes: VAD can cause dry, rough, and scaly skin, as well as the formation of small bumps on the skin (follicular hyperkeratosis).
• Impaired immunity: Vitamin A is essential for maintaining a healthy immune system, and VAD can increase the risk of infections, especially respiratory and diarrheal infections.
• Delayed growth and development: Children with VAD may experience delayed growth and development and may be more susceptible to infections and other health problems.
Physical Examination
Eye examination: The eyes are often the most affected by VAD, and a physical examination may reveal signs such as:
Night blindness: The individual has difficulty seeing in low light conditions, especially at night.
Dryness of the eyes: The eyes may appear dry, and the conjunctiva (the membrane that covers the white part of the eye) may be dry and inflamed.
Bitot’s spots: These are small, white, foamy patches that appear on the conjunctiva in severe cases of VAD.
Corneal ulcers: In advanced cases of VAD, the cornea (the transparent front part of the eye) can become dry and damaged, forming ulcers and scarring.
Skin examination: VAD can cause dry, rough, and scaly skin, as well as the formation of small bumps on the skin (follicular hyperkeratosis).
Immune system examination: Vitamin A is essential for maintaining a healthy immune system, and VAD can lead to impaired immunity, making individuals more susceptible to infections. A physical examination may reveal signs of respiratory or diarrheal infections, such as coughing, wheezing, or diarrhea.
Growth and development assessment: Children with VAD may experience delayed growth and development, and a physical examination may reveal signs of malnutrition, such as weight loss, thinning hair, and weak muscles.
Age group
Associated comorbidity
Associated activity
Acuity of presentation
Differential Diagnoses
• Dry eye syndrome: This is a condition characterized by a lack of sufficient lubrication and moisture in the eye. It can cause symptoms such as dryness, itching, burning, and blurred vision, like those of VAD.
• Measles: Measles is a viral infection that can cause symptoms such as fever, cough, runny nose, and conjunctivitis (inflammation of the conjunctiva), which can lead to the formation of white spots that resemble Bitot’s spots.
• Conjunctivitis: Conjunctivitis is an inflammation of the conjunctiva that can be caused by various factors, including infections, allergies, and irritants. It can cause symptoms like redness, itching, and discharge, like VAD’s.
• Keratomalacia: Keratomalacia is a condition caused by severe vitamin A deficiency that can lead to corneal ulcers and scarring like those seen in VAD. However, it is a more severe and advanced form of VAD.
• Atopic dermatitis: Atopic dermatitis, also known as eczema, is a chronic inflammatory skin condition that can cause dry, scaly, and itchy skin like those seen in VAD.
• Cystic fibrosis: Cystic fibrosis is a genetic disorder that can cause malabsorption of nutrients, including vitamin A, leading to symptoms such as growth delay, dry skin, and respiratory infections.
Laboratory Studies
Imaging Studies
Procedures
Histologic Findings
Staging
Treatment Paradigm
Dietary changes: Mild cases of VAD can be treated by increasing the intake of vitamin A-rich foods. The article suggests that the best sources of vitamin A are animal-based foods such as liver, eggs, and dairy products, as well as plant-based foods such as sweet potatoes, carrots, spinach, and mangoes. The dietary changes should be continued for an extended period to prevent further deficiency.
Oral vitamin A supplements: Moderate cases of VAD can be treated with oral vitamin A supplements. The article states that the recommended dose for children under six is 100,000-200,000 international units (IU) of vitamin A daily for two days, followed by a maintenance dose of 10,000-20,000 IU daily for two months. For adults, the recommended dose is 200,000-400,000 IU of vitamin A per day for two days, followed by a maintenance dose of 20,000-30,000 IU per day for two months.
Intramuscular or intravenous vitamin A supplements: Severe cases of VAD may require hospitalization and administration of high-dose vitamin A supplements through intramuscular or intravenous injections. The article states that the recommended dose for children under six is 200,000-400,000 IU of vitamin A, while the dose for adults is 400,000-600,000 IU.
Treatment of underlying conditions: In some cases, VAD may be caused by an underlying condition such as cystic fibrosis, celiac disease, or inflammatory bowel disease. Treating these conditions can help to correct the deficiency.
100,000 U/day intramuscular (IM) for 3 days; following 50,000 U/day for 2 weeks
Then follow with oral therapy:
10,000-20,000 U/day for 2 months
10,000-50,000 U/day orally for deficiency prophylaxis
Future Trends
Media Gallary
References
https://www.ncbi.nlm.nih.gov/books/NBK567744/
https://pubmed.ncbi.nlm.nih.gov/10920170/
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Vitamin A is an essential fat-soluble vitamin for various physiological processes, including vision, immune function, growth and development, and reproduction. Vitamin A deficiency (VAD) is a significant public health problem in many developing countries, particularly sub-Saharan Africa and South Asia.
VAD can result from inadequate dietary intake of vitamin A or impaired absorption and utilization of the vitamin. It is most common in populations that rely heavily on a limited number of staple foods that are low in vitamin A, such as rice, maize, and cassava. Individuals with medical conditions, such as inflammatory bowel disease or cystic fibrosis, may also be at increased risk for VAD due to impaired absorption of dietary fats.
The early stages of VAD may be asymptomatic or manifest as dryness and thickening of the skin and mucous membranes, including the eyes. As VAD progresses, it can lead to night blindness, a condition in which a person has difficulty seeing in low light or darkness. In severe cases, VAD can cause corneal damage, leading to blindness.
VAD is a significant public health concern because it can increase the risk of infectious diseases, particularly children. Vitamin A is necessary for maintaining the integrity of mucous membranes, which are the body’s first line of defense against pathogens. VAD can also impair immune function, making individuals more susceptible to infections.
Prevention and treatment of VAD typically involve increasing dietary intake of vitamin A-rich foods, such as liver, sweet potatoes, carrots, spinach, and mangoes. In some cases, vitamin A supplements may be recommended.
Vitamin A deficiency is a significant public health problem, particularly in developing countries. According to the World Health Organization (WHO), it is estimated that approximately 250 million preschool-age children are affected by vitamin A deficiency worldwide.
The epidemiology of vitamin A deficiency is complex and multifactorial. Several factors contribute to the prevalence of this deficiency, including inadequate dietary intake, poor absorption of vitamin A, and increased vitamin A requirements due to infections, particularly measles.
Populations most affected by vitamin A deficiency are those living in poverty, with limited access to food and a diet deficient in vitamin A-rich foods such as fruits, vegetables, and animal products. Vitamin A deficiency is also more common in regions with limited access to healthcare, sanitation, and education, as well as areas with high rates of infectious diseases.
Vitamin A deficiency (VAD) results from inadequate dietary intake of vitamin A or impaired absorption and utilization of the vitamin. Vitamin A is required for various physiological processes, including vision, immune function, growth and development, and reproduction. Vitamin A is necessary for maintaining the integrity of mucous membranes, which are the body’s first line of defense against pathogens. VAD can also impair immune function, making individuals more susceptible to infections. VAD can lead to a variety of pathophysiological changes:
One of the earliest manifestations of VAD is the development of keratinizing metaplasia in the respiratory, gastrointestinal, and urogenital tracts, which can thicken and dry the epithelial surfaces. VAD can also lead to changes in the structure and function of the skin, including impaired sebum production, increased susceptibility to infection, and impaired wound healing.
VAD can profoundly affect vision, particularly in low-light conditions. VAD can lead to the development of night blindness, which is a condition in which a person has difficulty seeing in low light or darkness. As VAD progresses, it can lead to corneal damage, resulting in permanent blindness.
In addition, VAD can lead to immune dysfunction, increasing the risk of infections. Vitamin A is necessary for the differentiation and maintenance of epithelial cells, and VAD can lead to impaired immune function and increased susceptibility to infection.
Vitamin A deficiency (VAD) can occur due to various factors, including:
• Inadequate dietary intake: Vitamin A is primarily found in animal-based foods, such as liver, eggs, dairy products, and fatty fish. Plant-based foods such as dark leafy greens, carrots, and sweet potatoes also contain vitamin A, but in the form of carotenoids, which need to be converted to retinol (the active form of vitamin A) by the body. In populations with limited access to a diverse range of foods, particularly those who rely heavily on a limited number of staple foods, VAD can occur due to inadequate dietary intake of vitamin A.
• Malabsorption: Certain medical conditions such as celiac disease, Crohn’s disease, cystic fibrosis, and pancreatic insufficiency can impair the body’s ability to absorb fat and fat-soluble vitamins such as vitamin A. This can lead to VAD, even in individuals who consume adequate amounts of vitamin A.
• Increased demand: Pregnant and breastfeeding women have an increased demand for vitamin A, which is necessary for fetal development and milk production. Infants and young children also have an increased demand for vitamin A, which is necessary for growth and development. VAD can occur in populations with limited access to a diverse range of foods due to increased demand for vitamin A during these life stages.
• Alcoholism: Chronic alcohol consumption can impair the body’s ability to store and utilize vitamin A, leading to VAD.
• Medications: Certain medications, such as cholestyramine (used to lower cholesterol) and mineral oil (used as a laxative), can interfere with the absorption of fat and fat-soluble vitamins, including vitamin A.
• Zinc deficiency: Zinc is necessary for converting provitamin A carotenoids to retinol. In populations with zinc deficiency, VAD can occur even if dietary intake of vitamin A is adequate.
• Age: Children under five are at the highest risk of developing vitamin A deficiency and are more likely to suffer from severe symptoms.
• Malnutrition: Malnourished individuals, especially those who do not consume a balanced diet with adequate vitamin A, are at a higher risk of developing VAD.
• Poverty: People living in poverty, especially in developing countries, are more likely to suffer from VAD due to limited access to nutrient-rich foods and supplements.
• Infections: Certain infections, such as measles and diarrhea, can reduce the body’s ability to absorb vitamin A and increase the risk of developing VAD.
• Alcoholism: Excessive alcohol consumption can impair the liver’s ability to store and release vitamin A, leading to a deficiency.
• Chronic diseases: Individuals with chronic diseases such as cystic fibrosis, Crohn’s disease, and liver disease are at a higher risk of developing VAD due to impaired absorption or storage of vitamin A.
• Pregnancy and lactation: Pregnant and lactating women have increased requirements for vitamin A, and a deficiency can have severe consequences for both the mother and the child.
• Night blindness: This is one of the earliest and most common symptoms of VAD. The individual has difficulty seeing in low-light conditions, especially at night.
• Dry eyes: VAD can cause dryness of the eyes, leading to eye inflammation and infections.
• Bitot’s spots: These are small, white, foamy patches that appear on the conjunctiva (the membrane that covers the white part of the eye) in severe cases of VAD.
• Corneal ulcers: In advanced cases of VAD, the cornea (the transparent front part of the eye) can become dry and damaged, forming ulcers and scarring.
• Xerophthalmia: This is a term used to describe a group of eye conditions caused by VAD. It includes night blindness, Bitot’s spots, dry eyes, and corneal ulcers.
• Skin changes: VAD can cause dry, rough, and scaly skin, as well as the formation of small bumps on the skin (follicular hyperkeratosis).
• Impaired immunity: Vitamin A is essential for maintaining a healthy immune system, and VAD can increase the risk of infections, especially respiratory and diarrheal infections.
• Delayed growth and development: Children with VAD may experience delayed growth and development and may be more susceptible to infections and other health problems.
Eye examination: The eyes are often the most affected by VAD, and a physical examination may reveal signs such as:
Night blindness: The individual has difficulty seeing in low light conditions, especially at night.
Dryness of the eyes: The eyes may appear dry, and the conjunctiva (the membrane that covers the white part of the eye) may be dry and inflamed.
Bitot’s spots: These are small, white, foamy patches that appear on the conjunctiva in severe cases of VAD.
Corneal ulcers: In advanced cases of VAD, the cornea (the transparent front part of the eye) can become dry and damaged, forming ulcers and scarring.
Skin examination: VAD can cause dry, rough, and scaly skin, as well as the formation of small bumps on the skin (follicular hyperkeratosis).
Immune system examination: Vitamin A is essential for maintaining a healthy immune system, and VAD can lead to impaired immunity, making individuals more susceptible to infections. A physical examination may reveal signs of respiratory or diarrheal infections, such as coughing, wheezing, or diarrhea.
Growth and development assessment: Children with VAD may experience delayed growth and development, and a physical examination may reveal signs of malnutrition, such as weight loss, thinning hair, and weak muscles.
• Dry eye syndrome: This is a condition characterized by a lack of sufficient lubrication and moisture in the eye. It can cause symptoms such as dryness, itching, burning, and blurred vision, like those of VAD.
• Measles: Measles is a viral infection that can cause symptoms such as fever, cough, runny nose, and conjunctivitis (inflammation of the conjunctiva), which can lead to the formation of white spots that resemble Bitot’s spots.
• Conjunctivitis: Conjunctivitis is an inflammation of the conjunctiva that can be caused by various factors, including infections, allergies, and irritants. It can cause symptoms like redness, itching, and discharge, like VAD’s.
• Keratomalacia: Keratomalacia is a condition caused by severe vitamin A deficiency that can lead to corneal ulcers and scarring like those seen in VAD. However, it is a more severe and advanced form of VAD.
• Atopic dermatitis: Atopic dermatitis, also known as eczema, is a chronic inflammatory skin condition that can cause dry, scaly, and itchy skin like those seen in VAD.
• Cystic fibrosis: Cystic fibrosis is a genetic disorder that can cause malabsorption of nutrients, including vitamin A, leading to symptoms such as growth delay, dry skin, and respiratory infections.
Dietary changes: Mild cases of VAD can be treated by increasing the intake of vitamin A-rich foods. The article suggests that the best sources of vitamin A are animal-based foods such as liver, eggs, and dairy products, as well as plant-based foods such as sweet potatoes, carrots, spinach, and mangoes. The dietary changes should be continued for an extended period to prevent further deficiency.
Oral vitamin A supplements: Moderate cases of VAD can be treated with oral vitamin A supplements. The article states that the recommended dose for children under six is 100,000-200,000 international units (IU) of vitamin A daily for two days, followed by a maintenance dose of 10,000-20,000 IU daily for two months. For adults, the recommended dose is 200,000-400,000 IU of vitamin A per day for two days, followed by a maintenance dose of 20,000-30,000 IU per day for two months.
Intramuscular or intravenous vitamin A supplements: Severe cases of VAD may require hospitalization and administration of high-dose vitamin A supplements through intramuscular or intravenous injections. The article states that the recommended dose for children under six is 200,000-400,000 IU of vitamin A, while the dose for adults is 400,000-600,000 IU.
Treatment of underlying conditions: In some cases, VAD may be caused by an underlying condition such as cystic fibrosis, celiac disease, or inflammatory bowel disease. Treating these conditions can help to correct the deficiency.
100,000 U/day intramuscular (IM) for 3 days; following 50,000 U/day for 2 weeks
Then follow with oral therapy:
10,000-20,000 U/day for 2 months
10,000-50,000 U/day orally for deficiency prophylaxis
https://www.ncbi.nlm.nih.gov/books/NBK567744/
https://pubmed.ncbi.nlm.nih.gov/10920170/
medtigo
Vitamin A Deficiency
Updated :
September 5, 2023
Vitamin A is an essential fat-soluble vitamin for various physiological processes, including vision, immune function, growth and development, and reproduction. Vitamin A deficiency (VAD) is a significant public health problem in many developing countries, particularly sub-Saharan Africa and South Asia.
VAD can result from inadequate dietary intake of vitamin A or impaired absorption and utilization of the vitamin. It is most common in populations that rely heavily on a limited number of staple foods that are low in vitamin A, such as rice, maize, and cassava. Individuals with medical conditions, such as inflammatory bowel disease or cystic fibrosis, may also be at increased risk for VAD due to impaired absorption of dietary fats.
The early stages of VAD may be asymptomatic or manifest as dryness and thickening of the skin and mucous membranes, including the eyes. As VAD progresses, it can lead to night blindness, a condition in which a person has difficulty seeing in low light or darkness. In severe cases, VAD can cause corneal damage, leading to blindness.
VAD is a significant public health concern because it can increase the risk of infectious diseases, particularly children. Vitamin A is necessary for maintaining the integrity of mucous membranes, which are the body’s first line of defense against pathogens. VAD can also impair immune function, making individuals more susceptible to infections.
Prevention and treatment of VAD typically involve increasing dietary intake of vitamin A-rich foods, such as liver, sweet potatoes, carrots, spinach, and mangoes. In some cases, vitamin A supplements may be recommended.
Vitamin A deficiency is a significant public health problem, particularly in developing countries. According to the World Health Organization (WHO), it is estimated that approximately 250 million preschool-age children are affected by vitamin A deficiency worldwide.
The epidemiology of vitamin A deficiency is complex and multifactorial. Several factors contribute to the prevalence of this deficiency, including inadequate dietary intake, poor absorption of vitamin A, and increased vitamin A requirements due to infections, particularly measles.
Populations most affected by vitamin A deficiency are those living in poverty, with limited access to food and a diet deficient in vitamin A-rich foods such as fruits, vegetables, and animal products. Vitamin A deficiency is also more common in regions with limited access to healthcare, sanitation, and education, as well as areas with high rates of infectious diseases.
Vitamin A deficiency (VAD) results from inadequate dietary intake of vitamin A or impaired absorption and utilization of the vitamin. Vitamin A is required for various physiological processes, including vision, immune function, growth and development, and reproduction. Vitamin A is necessary for maintaining the integrity of mucous membranes, which are the body’s first line of defense against pathogens. VAD can also impair immune function, making individuals more susceptible to infections. VAD can lead to a variety of pathophysiological changes:
One of the earliest manifestations of VAD is the development of keratinizing metaplasia in the respiratory, gastrointestinal, and urogenital tracts, which can thicken and dry the epithelial surfaces. VAD can also lead to changes in the structure and function of the skin, including impaired sebum production, increased susceptibility to infection, and impaired wound healing.
VAD can profoundly affect vision, particularly in low-light conditions. VAD can lead to the development of night blindness, which is a condition in which a person has difficulty seeing in low light or darkness. As VAD progresses, it can lead to corneal damage, resulting in permanent blindness.
In addition, VAD can lead to immune dysfunction, increasing the risk of infections. Vitamin A is necessary for the differentiation and maintenance of epithelial cells, and VAD can lead to impaired immune function and increased susceptibility to infection.
Vitamin A deficiency (VAD) can occur due to various factors, including:
• Inadequate dietary intake: Vitamin A is primarily found in animal-based foods, such as liver, eggs, dairy products, and fatty fish. Plant-based foods such as dark leafy greens, carrots, and sweet potatoes also contain vitamin A, but in the form of carotenoids, which need to be converted to retinol (the active form of vitamin A) by the body. In populations with limited access to a diverse range of foods, particularly those who rely heavily on a limited number of staple foods, VAD can occur due to inadequate dietary intake of vitamin A.
• Malabsorption: Certain medical conditions such as celiac disease, Crohn’s disease, cystic fibrosis, and pancreatic insufficiency can impair the body’s ability to absorb fat and fat-soluble vitamins such as vitamin A. This can lead to VAD, even in individuals who consume adequate amounts of vitamin A.
• Increased demand: Pregnant and breastfeeding women have an increased demand for vitamin A, which is necessary for fetal development and milk production. Infants and young children also have an increased demand for vitamin A, which is necessary for growth and development. VAD can occur in populations with limited access to a diverse range of foods due to increased demand for vitamin A during these life stages.
• Alcoholism: Chronic alcohol consumption can impair the body’s ability to store and utilize vitamin A, leading to VAD.
• Medications: Certain medications, such as cholestyramine (used to lower cholesterol) and mineral oil (used as a laxative), can interfere with the absorption of fat and fat-soluble vitamins, including vitamin A.
• Zinc deficiency: Zinc is necessary for converting provitamin A carotenoids to retinol. In populations with zinc deficiency, VAD can occur even if dietary intake of vitamin A is adequate.
• Age: Children under five are at the highest risk of developing vitamin A deficiency and are more likely to suffer from severe symptoms.
• Malnutrition: Malnourished individuals, especially those who do not consume a balanced diet with adequate vitamin A, are at a higher risk of developing VAD.
• Poverty: People living in poverty, especially in developing countries, are more likely to suffer from VAD due to limited access to nutrient-rich foods and supplements.
• Infections: Certain infections, such as measles and diarrhea, can reduce the body’s ability to absorb vitamin A and increase the risk of developing VAD.
• Alcoholism: Excessive alcohol consumption can impair the liver’s ability to store and release vitamin A, leading to a deficiency.
• Chronic diseases: Individuals with chronic diseases such as cystic fibrosis, Crohn’s disease, and liver disease are at a higher risk of developing VAD due to impaired absorption or storage of vitamin A.
• Pregnancy and lactation: Pregnant and lactating women have increased requirements for vitamin A, and a deficiency can have severe consequences for both the mother and the child.
• Night blindness: This is one of the earliest and most common symptoms of VAD. The individual has difficulty seeing in low-light conditions, especially at night.
• Dry eyes: VAD can cause dryness of the eyes, leading to eye inflammation and infections.
• Bitot’s spots: These are small, white, foamy patches that appear on the conjunctiva (the membrane that covers the white part of the eye) in severe cases of VAD.
• Corneal ulcers: In advanced cases of VAD, the cornea (the transparent front part of the eye) can become dry and damaged, forming ulcers and scarring.
• Xerophthalmia: This is a term used to describe a group of eye conditions caused by VAD. It includes night blindness, Bitot’s spots, dry eyes, and corneal ulcers.
• Skin changes: VAD can cause dry, rough, and scaly skin, as well as the formation of small bumps on the skin (follicular hyperkeratosis).
• Impaired immunity: Vitamin A is essential for maintaining a healthy immune system, and VAD can increase the risk of infections, especially respiratory and diarrheal infections.
• Delayed growth and development: Children with VAD may experience delayed growth and development and may be more susceptible to infections and other health problems.
Eye examination: The eyes are often the most affected by VAD, and a physical examination may reveal signs such as:
Night blindness: The individual has difficulty seeing in low light conditions, especially at night.
Dryness of the eyes: The eyes may appear dry, and the conjunctiva (the membrane that covers the white part of the eye) may be dry and inflamed.
Bitot’s spots: These are small, white, foamy patches that appear on the conjunctiva in severe cases of VAD.
Corneal ulcers: In advanced cases of VAD, the cornea (the transparent front part of the eye) can become dry and damaged, forming ulcers and scarring.
Skin examination: VAD can cause dry, rough, and scaly skin, as well as the formation of small bumps on the skin (follicular hyperkeratosis).
Immune system examination: Vitamin A is essential for maintaining a healthy immune system, and VAD can lead to impaired immunity, making individuals more susceptible to infections. A physical examination may reveal signs of respiratory or diarrheal infections, such as coughing, wheezing, or diarrhea.
Growth and development assessment: Children with VAD may experience delayed growth and development, and a physical examination may reveal signs of malnutrition, such as weight loss, thinning hair, and weak muscles.
• Dry eye syndrome: This is a condition characterized by a lack of sufficient lubrication and moisture in the eye. It can cause symptoms such as dryness, itching, burning, and blurred vision, like those of VAD.
• Measles: Measles is a viral infection that can cause symptoms such as fever, cough, runny nose, and conjunctivitis (inflammation of the conjunctiva), which can lead to the formation of white spots that resemble Bitot’s spots.
• Conjunctivitis: Conjunctivitis is an inflammation of the conjunctiva that can be caused by various factors, including infections, allergies, and irritants. It can cause symptoms like redness, itching, and discharge, like VAD’s.
• Keratomalacia: Keratomalacia is a condition caused by severe vitamin A deficiency that can lead to corneal ulcers and scarring like those seen in VAD. However, it is a more severe and advanced form of VAD.
• Atopic dermatitis: Atopic dermatitis, also known as eczema, is a chronic inflammatory skin condition that can cause dry, scaly, and itchy skin like those seen in VAD.
• Cystic fibrosis: Cystic fibrosis is a genetic disorder that can cause malabsorption of nutrients, including vitamin A, leading to symptoms such as growth delay, dry skin, and respiratory infections.
Dietary changes: Mild cases of VAD can be treated by increasing the intake of vitamin A-rich foods. The article suggests that the best sources of vitamin A are animal-based foods such as liver, eggs, and dairy products, as well as plant-based foods such as sweet potatoes, carrots, spinach, and mangoes. The dietary changes should be continued for an extended period to prevent further deficiency.
Oral vitamin A supplements: Moderate cases of VAD can be treated with oral vitamin A supplements. The article states that the recommended dose for children under six is 100,000-200,000 international units (IU) of vitamin A daily for two days, followed by a maintenance dose of 10,000-20,000 IU daily for two months. For adults, the recommended dose is 200,000-400,000 IU of vitamin A per day for two days, followed by a maintenance dose of 20,000-30,000 IU per day for two months.
Intramuscular or intravenous vitamin A supplements: Severe cases of VAD may require hospitalization and administration of high-dose vitamin A supplements through intramuscular or intravenous injections. The article states that the recommended dose for children under six is 200,000-400,000 IU of vitamin A, while the dose for adults is 400,000-600,000 IU.
Treatment of underlying conditions: In some cases, VAD may be caused by an underlying condition such as cystic fibrosis, celiac disease, or inflammatory bowel disease. Treating these conditions can help to correct the deficiency.
https://www.ncbi.nlm.nih.gov/books/NBK567744/
https://pubmed.ncbi.nlm.nih.gov/10920170/
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