What is Vitamin A Deficiency?
Vitamin A is a vital nutrient that helps with cell growth, metabolism, immune system, vision, and reproduction. Not getting enough vitamin A can lead to health problems, and it’s a common issue worldwide, mainly affecting young children in poor regions. This vitamin comes from foods like dark green vegetables, orange vegetables, dairy, liver, and fish. It’s broken down by certain enzymes in our bodies and mixed with dietary fats and bile acids. Most of this Vitamin A is stored in certain liver cells, but some are also stored in body fat and the pancreas.
The recommended amount of daily vitamin A intake for healthy adults is 700 micrograms for women and 900 micrograms for men. For children, pregnant women, and breastfeeding women, the amount varies from 300 to 900, 770, and 1300 micrograms/day, respectively. To avoid vitamin A deficiency in children aged 1 to 5, they need at least 200 micrograms/day. A good way to tell if someone is getting enough vitamin A is to measure their blood levels of retinol, a form of vitamin A. Lack of vitamin A is suggested if the retinol level is less than 20 micrograms/dL.
When the retinol concentration drops below 10 micrograms/dL, symptoms affecting the eye related to vitamin A deficiency can begin to appear. Vitamin A in our diet comes from either fruits and vegetables, in the form of carotenoids, or from animal products, in the form of retinoids. Carotenoids are like a Vitamin A source and retinoids are the active form of the vitamin. Our body absorbs these forms of the nutrient differently. Retinoids have a high absorption rate, while the absorption of carotenoids depends on the type of food consumed.
According to the Centers for Disease Control and Prevention, in a mixed diet of fruits and vegetables, an estimated 12 carotenoids are absorbed for every one retinoid. This can be problematic in developing countries where people rarely eat meat, dairy, or vegetables high in carotenoids, making it difficult to get enough vitamin A.
What Causes Vitamin A Deficiency?
In parts of the world where resources are scarce, lack of proper nutrition and constant issues with digestive infections often result in a lack of crucial nutrients, making vitamin A deficiency very common. This problem can become even more complex for children in these areas because they commonly also lack zinc, which is necessary for the body to absorb vitamin A and generate a transport protein called retinol-binding protein (RBP).
In many of these regions, measles is also widespread and it’s known to cause a sharp decrease of more than 30% in vitamin A levels in the body. It also disrupts generation of RBP and causes a high amount of vitamin A to be excreted in urine. Furthermore, the presence of measles increases the body’s need for vitamin A due to the damage it causes to the digestive tissues.
The amount of vitamin A found in breast milk is affected by the mother’s nutrition. In places with limited resources, the average concentration of vitamin A in breast milk just covers an infant’s daily requirement, leaving no chance to build up reserves in the liver. As a result, children often end up lacking vitamin A shortly after they stop breastfeeding. On the other hand, in developed parts of the world where foods rich in vitamin A are readily available and sanitation, water, and healthcare are significantly better, vitamin A deficiency is quite rare. If it does occur, it’s usually because of some underlying diseases that interfere with the body’s ability to absorb nutrients.
In developed countries, conditions of the pancreas, liver, and intestines are cited as main causes of vitamin A deficiency. For example, inflammatory bowel disease (IBD) can lead to such deficiency by causing chronic inflammation in the tissues of the intestine and reducing food intake. Similarly, chronic liver disease has been associated with vitamin A deficiency but the exact process remains unclear. Some theories suggest decreased production of bile acids necessary for absorption or altered patterns of storage. Pancreatic insufficiency can also result in vitamin A deficiency because of decreased functioning of the pancreas and lack of production of the enzymes required for absorption. Bariatric surgeries that bypass part of the intestine to prevent absorption of fats can inadvertently lead to poor absorption of fat-soluble vitamins, including vitamin A. Finally, prematurely born babies are also prone to vitamin A deficiency due to their underdeveloped digestive systems, limited vitamin A reserves and rapidly growing bodies requiring more nutrition.
Risk Factors and Frequency for Vitamin A Deficiency
Vitamin A deficiency (VAD) is most common in children under five years, especially in developing countries. In fact, about 30% of these children are estimated to have VAD, contributing to 2% of all deaths within this group. Pregnant and breastfeeding women also face an increased risk, with a 2019 study in Ethiopia finding that 76% of breastfeeding mothers had VAD. However, VAD doesn’t have a preference for gender.
On the other hand, VAD is pretty rare in the United States, affecting just about 0.3% of the population in 2013. Most of the time, symptoms of VAD arise from issues affecting nutrient absorption or severely restricted diets. Among children with inflammatory bowel disease (IBD), 16% had VAD at diagnosis, with it being more prevalent in Crohn’s disease than in ulcerative colitis.
- Patients with severe liver disease waiting for a transplant have a 70% prevalence of VAD, with the severity of the liver disease positively linked to the prevalence of VAD.
- About 35% of patients with chronic problems in producing pancreatic enzymes have VAD, even though 84% were on replacement therapy.
- 70% of patients who underwent biliopancreatic diversion (a type of weight loss surgery) developed VAD three years after the surgery.
- At birth, 66% of preterm babies are vitamin A deficient, and at 36 weeks of gestational age, 82% had a deficiency due to their high needs and low absorption levels.
Signs and Symptoms of Vitamin A Deficiency
If a patient has a history of conditions that affect nutrient absorption, like inflammatory bowel disease, chronic gastrointestinal infections, liver disease, pancreatitis, being born prematurely, or measles, they could be at risk of vitamin A deficiency. This risk is also higher in those living in nations with fewer resources and in pregnant or breastfeeding women who aren’t getting proper nutrition. Chronic vitamin A deficiency typically starts with difficulty seeing in the dark, becoming sick often, a rough skin condition called xeroderma, and another skin issue known as phrynoderma, which usually shows up on parts of the body like the elbows, shoulders, and buttocks.
As the deficiency gets worse, patients may develop signs of xerophthalmia, a severe dryness of the eyes. This could lead to the formation of Bitot’s spots, which are frothy patches that form on the surface of the eyes and conjunctival xerosis, a condition that appears as wrinkling of the conjunctiva, the clear tissue that covers the white part of the eye. If the Vitamin A deficiency isn’t managed, the patient can develop corneal xerosis (dryness of the cornea, the eye’s outer layer), corneal ulcers, and eventually keratomalacia, a condition that softens the cornea. If the ulcers heal, they can lead to corneal scarring and loss of vision. It’s also possible for a patient with an acute deficiency to suffer from corneal dryness and ulcers without first having difficulty seeing at night or Bitot’s spots. This is especially common in patients who also have an infection, like measles. Phrynoderma can also be seen in those with vitamin A deficiency, but it’s usually associated with other nutritional shortfalls too.
Testing for Vitamin A Deficiency
If a doctor suspects vitamin A deficiency in a person, they typically look for certain symptoms during a physical exam. One key sign, called xerophthalmia, is almost exclusively associated with lack of vitamin A.
For patients whose symptoms and medical history don’t provide a clear picture, the doctor may order a blood test that measures levels of retinol, a type of vitamin A. If this test shows less than 20 micrograms per deciliter, this indicates a deficiency. However, it’s possible for people to have normal retinol levels in their blood even if their bodies are running low on vitamin A. This happens because the liver keeps circulating levels of retinol stable, even if the overall reserves are depleted.
The most accurate way to determine total body vitamin A is to measure the amount of retinol in the liver through a biopsy procedure. But because liver biopsies carry their own risks, they are usually not used to check vitamin A levels except in research studies.
Treatment Options for Vitamin A Deficiency
The main way to treat a lack of vitamin A, known as vitamin A deficiency, is to take vitamin A supplements. Research has shown that these supplements help to decrease illness and death in children who don’t get enough vitamin A. The supplements are typically very effective when the blood vitamin A level is below 20 micrograms per deciliter. However, if a patient’s level is above 30 micrograms per deciliter, the supplements are unnecessary, and they should just stick to their diet.
The World Health Organization (WHO) has a specific plan for areas where vitamin A deficiency is common. They suggest kids between 6-11 months get a single dose of 100,000 IU (International Units), which should be followed by doses of 200,000 IU every 4 to 6 months until they turn 5. Pregnant women who are at risk should also take smaller doses, because high doses can cause harm to the fetus. The safe dosages suggested by the WHO are either 10,000 IU daily or 25,000 IU weekly for 12 weeks. They no longer recommend supplements for babies below 6 months or new mothers.
There aren’t specific international guidelines for how to give vitamin A supplements in areas where resources are abundant. The dosage is determined by how severe the deficiency is and the health provider’s judgement. The WHO suggests treating eye problems linked to vitamin A deficiency with doses of 50,000 IU for children less than 6 months old, 100,000 IU for children between 6-12 months old, and 200,000 IU for children older than 12 months. This should be given daily for 2 days, along with an extra dose after 2 weeks. If a patient has a severe case of measles, they should be given the same doses, whether or not they are deficient in vitamin A. If the deficiency is due to poor absorption of nutrients, also known as malabsorption, the supplement may need to be given through a muscle injection. Patients who also lack zinc will need additional supplements because they won’t respond well to the vitamin A supplements alone.
In countries with lots of resources, there are specific recommendations for certain groups. For instance, patients who have had weight loss surgery should take 10,000 IU of vitamin A supplements daily. This can be adjusted based on regular blood tests. Some might need as many as 100,000 IU daily. Guidelines for premature babies aren’t clear yet, but recent studies suggest that giving 10,000 IU every other day to very small newborn babies for 4 weeks can significantly lower death rates and reduce the need for oxygen, risks of infection, and the length of the hospital stay. Giving 1,500 IU daily to extremely premature babies can significantly decrease eye problems and lung issues. If vitamin A deficiency is linked to other malabsorption problems, the treatment should be personalized.
What else can Vitamin A Deficiency be?
If a person is experiencing signs of vitamin A deficiency, like night blindness and eye spots known as Bitot spots, it’s crucial to be aware that there could be other reasons for these symptoms. For instance, night blindness could be due to conditions like retinitis pigmentosa or other rare eye disorders. Cataracts, which are cloudy patches in the lens of the eye, and nearsightedness could also cause night blindness.
Similarly, Bitot spots might appear not only due to vitamin A deficiency but also in cases of niacin deficiency, another essential nutrient for the body. Some eye conditions, like pinguecula and pterygium, may also look similar to Bitot spots. Therefore, it’s important to consider all these possibilities when diagnosing vitamin A deficiency to ensure the correct treatment is given.
What to expect with Vitamin A Deficiency
The outcome of vitamin A deficiency largely depends on how severe the condition is when treatment begins. If treatment starts promptly, patients who have vitamin A deficiency but haven’t shown any symptoms yet generally have a very positive outcome without any long-term issues. Even in more severe cases, the treatment can start showing improvements within a week.
Early eye-related symptoms like night blindness, a dry surface of the eyes, and small, foamy spots on the whites of the eyes, usually clear up entirely within about two months of taking vitamin A supplements. On the other hand, a dry and ulcerated cornea can result in scarring, which may cause permanent loss of vision even with treatment. Once these eye symptoms start appearing, patients become more vulnerable to infections.
In particular, preschool children with vitamin A deficiency show an increased risk of dying from infections in the digestive system, lungs, and other areas if they show these eye symptoms.
For children, night blindness triples the risk of death compared to children who have vitamin A deficiency without any symptoms. If children have both the foamy spots and night blindness, their risk of death is nine times higher. Sadly, almost two-thirds of children with keratomalacia, a condition where the cornea becomes extremely dry and ulcerated, die within months.
Possible Complications When Diagnosed with Vitamin A Deficiency
If someone has a severe vitamin A deficiency, they might lose their vision or even go blind. They can also more easily catch infections and have a weaker immune system. This leaves them at high risk of death.
Preventing Vitamin A Deficiency
Eating a balanced diet that’s rich in nutrients can help prevent a deficiency in vitamin A for people who are generally healthy and have no problems absorbing nutrients from their food. In wealthier areas, most people can easily access foods like vegetables, meats, and essential food items that have been enriched with vitamin A. Whereas, in less wealthy countries, programs have been established to provide high doses of vitamin A supplements at intervals recommended by the World Health Organization.
Along with these supplement programs, education on nutrition, breastfeeding, and the signs of Vitamin A deficiency are also provided. The success of these programs varies depending on the area. More recently, the focus has shifted from simply providing supplements to addressing the root cause of Vitamin A deficiency. This includes enriching food with vitamins and providing education about it. Many essential food items are now fortified with critical micronutrients. Genetic modifications have also been made to certain crops like rice, potatoes, wheat, and soybeans to increase their vitamin A content.
These ‘biofortified’ crops are not only beneficial for our health, but they’re also financially and agronomically feasible to produce, making them a sustainable way to tackle Vitamin A deficiency.
