Vitamin A deficiency results from a dietary intake of vitamin A that is inadequate. The NHS says you should be able to get all the vitamin A you need by eating a varied and balanced diet, but if you choose to take a supplement make sure not take too much because this could be harmful. Having an average of 1.5mg a day or less of vitamin A from diet and supplements combined is unlikely to cause any harm.
There are a number of signs which may indicate that you are lacking in vitamin A.
According to the NHS these can include signs on your hair, mouth and eyes.
The Whittington Hospital NHS Trust says: “Sometimes in early vitamin A deficiency people also get dry hair, dry mouth, dry/itchy/bumpy skin, broken nails, and more frequent infections.”
It warns: “If vitamin A deficiency is severe or is allowed to progress, serious problems can develop. The most serious problem is permanent blindness.”
There are also a number of other symptoms. The NHS Trust says these include loss of tears, sores in the eyes, fatigue, dry cracked lips, and mouth sores.
Other people may experience diarrhea, bladder infections, vaginal infections, upper and lower respiratory infections, or poor and delayed wound healing.
It also says that changes in vision are often the first noticeable sign of vitamin A deficiency, as you may notice that you cannot see as well at night.
For example, you may notice that you need to turn on lights earlier in the evening.
The NHS says: “Any vitamin A your body does not need immediately is stored for future use. This means you do not need it every day.”
The World Health Organization (WHO) says: “Night blindness is one of the first signs of vitamin A deficiency.
“In its more severe forms, vitamin A deficiency contributes to blindness by making the cornea very dry, thus damaging the retina and cornea.”
It adds: “Even mild, subclinical deficiency can be a problem, because it may increase children’s risk for respiratory and diarrhoeal infections, decrease growth rates, slow bone development and decrease the likelihood of survival from serious illness.”
The NHS has outlined some good sources of vitamin A, retinol, which include cheese, eggs and oily fish.
They add fortified low-fat spreads, milk and yoghurt, and liver and liver products such as liver pâté.
“If you eat liver every week, do not take supplements that contain vitamin A,” it says.
The health body says that you can also get vitamin A by including good sources of beta-carotene in your diet, as your body can convert this into retinol.
The main food sources of beta-carotene are yellow, red and green vegetables, such as spinach, carrots, sweet potatoes and red peppers.
It warns that some research suggests that having more than an average of 1.5 mg a day of vitamin A over many years may affect your bones, making them more likely to fracture.
It says: “Having an average of 1.5mg a day or less of vitamin A from diet and supplements combined is unlikely to cause any harm.”
The requirement for vitamin A is higher in pregnant and lactating women.