Vitamin A is a fat-soluble nutrient that helps produce the light-sensing pigment in the retina called rhodopsin. It is also needed for the development of healthy immune and inflammatory responses. Deficiency can occur due to inadequate intake, fat malabsorption, and liver disorders. Symptoms include night blindness and Bitot spots, which are oval or triangular areas of foamy skin on the eye's surface.
Deficiency Alerts
A vitamin A deficiency occurs when you don’t have enough of this nutrient in your diet. It can affect the skin, eyes and immune system. It’s more common in the developing world, where lack of access to food and medical care makes it hard to get the nutrients you need. Mild forms of vitamin A deficiency may cause no symptoms at all. But more severe deficiency can cause a scaly rash on the skin, tiredness, poor vision in darkness (night blindness) and thinning of the cornea on the front of the eye (xerophthalmia).
Vitamin A is found naturally in liver, eggs and milk, as well as dark green leafy vegetables, carrots and yellow and orange non-citrus fruits. It can also be absorbed from supplements that contain beta-carotene or retinol. It’s important to speak to a doctor or dietitian about how much vitamin A you need for good health.
It’s rare to get too much preformed vitamin A from the diet, but taking high doses of vitamin A can be dangerous. Acute hypervitaminosis A, or toxicity, can result from one or a few very high doses of vitamin A and can cause severe headache, blurred vision, nausea, aching muscles and problems with coordination. It can even lead to coma and death [82].
Health Impact
While vitamin A deficiency is rare in the US, it occurs globally in areas where people don't have access to enough preformed vitamin A (retinol) and provitamin A carotenoids from animal-based foods. Specifically, this is seen in many poor nations in Africa and South Asia. Children and pregnant or breastfeeding women are at the greatest risk of severe complications from this deficiency, including night blindness and harm to the immune or disease-fighting system that increases their risk of dying from malaria, diarrhea, measles and other infections.
The most common signs of vitamin A deficiency are a lack of vision in the dark (night blindness) and dryness of the whites of the eyes (conjunctiva) and cornea on the front of the eye (xerophthalmia). It also causes rough skin, a reduction in the thickness of the lining of the lungs, intestines and urinary tract, and oval or triangular foamy deposits on the whites of the eyes (Bitot spots). Deficiency is known to impair the function of the innate 'first line of defence' part of the immune system as well as to disrupt the gut microbiome. It also affects hormone production and embryonic development. In addition to its impact on vision and immune health, vitamin A is essential for several metabolic processes, including cellular energy metabolism, growth and development.
Remedies
Vitamin A is a fat-soluble nutrient essential for healthy vision, immune system, fertility and skin. It comes from two sources: preformed vitamin A (also known as retinol) found in meat and dairy, and the plant vitamin A – carotenoids, which are found in green, yellow, orange and red fruits and vegetables. The body converts carotenoids to preformed vitamin A. Vitamin A deficiency is rare in first world nutrient-rich countries, but it affects millions worldwide.
Mild deficiency can cause tiredness, a general feeling of illness and dry eyes. In more serious cases, the eyes develop a hazy film and ulcers on the cornea (keratomalacia) and the mucus membranes of the respiratory, gastrointestinal and urinary tracts become thicker and drier (keratinization).
Deficiency is more likely in people with conditions that interfere with absorption or storage of vitamin A such as celiac disease, cystic fibrosis, pancreatic insufficiency, duodenal atresia, chronic diarrhea, chronic giardiasis and cirrhosis. In pregnancy, low vitamin A levels can lead to poorer bone and teeth development in infants and delays in fetal growth and weight gain. Those at risk should regularly check in with their doctor to keep track of their vitamin A levels. This can be done with a simple blood test. Dietary supplements may also be recommended to help keep vitamin A levels in balance.