A Vitamin A deficiency can cause night blindness.

Vitamin A (Retinol) Signs of Deficiency, Overdose, Toxicity

Signs of Vitamin A (Retinol) Deficiency

Just as vitamin A has many health benefits, a deficiency of this important nutrient can result in various problems. A deficiency of vitamin A (retinol) can happen when a person consumes a diet that doesn’t contain sufficient quantities of vitamin A and beta-carotene. Beta-carotene is the vegetable form of vitamin A which is easily converted into vitamin A in the body. Signs of a deficiency will generally show up after an extended period of having a deficit of the nutrient.

It is more rare to see a deficiency in developed countries than poor ones. Food sources of vitamin A are plentiful in more developed nations, so most people get adequate amounts through regular diet. Those who are the most likely to suffer from a deficiency are young children, women who are pregnant, and women who are breastfeeding.

Signs and consequences of a vitamin A deficiency include:

  • Night blindness, and other problems with the eyes or vision.
  • Increased susceptibility to infection, as a deficiency can impact the immune system.
  • There may be changes in appearance. Particularly dry or scaly skin.
  • An extreme deficiency can eventually reduce lung and intestinal function.

During pregnancy, problems can result from a deficiency of vitamin A. This is more likely during the third trimester. Late in the pregnancy, the demand for the vitamin is elevated. Not only can it cause the mother to get night blindness, but it can also result in problems with the placenta and the baby having a low birth weight. This is why it is vital for pregnant women to ensure they get enough vitamin A.

A deficiency of vitamin A can be harmful during pregnancy.

Adequate vitamin A intake is critical during pregnancy.

Vitamin A (Retinol) Overdose and Toxicity

Preformed vitamin A (from animal sources and some supplements) is quickly absorbed by the body, but used and cleared out more slowly. So, taking too much vitamin A, too quickly, could result in an overdose (acute toxicity). This could potentially harm the bones and the skin, resulting in tissues that are weak and brittle. Excessive intake of vitamin A during pregnancy could result in birth defects. Also, it can cause nausea, vomiting, and extreme fatigue. Liver damage, swelling of the brain, and coma could occur in extreme situations.

Ingesting high amounts of vitamin A over a long period can result in chronic toxicity. A daily intake of more than 25,000 IU of per day, for extended periods, can result in chronic toxicity. Acute toxicity of vitamin A generally requires an intake of hundreds of thousands of IU.

Symptoms of a chronic vitamin A toxicity include fatigue, weakness, lack of appetite, digestive discomfort, vomiting, soreness, moodiness, headaches, dry/brittle/yellow skin, and hair loss.

Overdose and chronic toxicity of vitamin A are rare, and only occur with excessive supplementation. If you take a quality supplement and take the correct dosage, you shouldn’t need to worry.

Tolerable Upper Level of Vitamin A

The National Academy of Sciences has set daily intake limits for nutrients. These are safe daily amounts to ingest. For vitamin A, the tolerable upper level is:

  • 0.6 milligrams a day for infants and children 0–3 years old
  • 0.9 milligrams a day for children 4–8 years old
  • 1.7 milligrams a day for children 9–13 years old
  • 2.8 milligrams a day for teenagers 14–18 years old
  • 3.0 milligrams a day for adults over 18
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