Vitamin A Cautions

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General warnings and precautions

Certain people should not take high vitamin A supplements:

Women who are pregnant
Women who are pregnant should not take more than the upper tolerable limit of vitamin A due to the risk on the unborn foetus - high levels of vitamin A supplements could cause birth defects.

Certain people should not take vitamin A supplements without first consulting their doctor for advice:

People who drink excessive alcohol
The liver of a person who drinks a lot of alcohol may be irritated by and may not be able to handle high vitamin A supplementation. This means that the liver may not be able to metabolise and use the vitamin A properly causing toxicity effects.
People with cystic fibrosis
People with cystic fibrosis may have low levels of vitamin A (as this vitamin is needed for ensuring healthy mucous membranes and it is not healthy in people with cystic fibrosis) and could need supplementation. People with this condition need to seek their doctor's advice about taking vitamin A.
People with diabetes
People with diabetes may have low levels of vitamin A due to their condition and could need supplementation. People with this condition need to seek their doctor's advice about taking vitamin A.
People with gastrointestinal disorders (with diarrhoea)
People that have any type of gastrointestinal disorder that has associated diarrhoea may be excreting a lot of their vitamin A out in their diarrhoea and could need supplementation.
People with kidney disease
People with kidney disease may have low levels of vitamin A due to their condition and could need supplementation. People with this condition need to seek their doctor's advice about taking vitamin A.
People with liver disease
People with liver disease may have low levels of vitamin A due to their condition and could need supplementation. People with this condition need to seek their doctor's advice about taking vitamin A.
People with overactive thyroid function
People with an overactive thyroid may have low levels of vitamin A due to their condition and could need supplementation. People with this condition need to seek their doctor's advice about taking vitamin A.
People with disorders of the pancreas, including viral pancreatitis
People with disorders of the pancreas (including viral pancreatitis) may have low levels of vitamin A due to their condition and could need supplementation. People with this condition need to seek their doctor's advice about taking vitamin A.

Women who are pregnant should not take vitamin A supplements, as excessive levels can damage the unborn child

Toxic Levels of vitamin A

Vitamin A is toxic at doses greater than 22,500mcg (or 75,000IU) per day.

Vitamin D supplementation helps to reduce vitamin A toxicity, so should be taken together.

Overdosage and Toxicity Symptoms

High levels of vitamin A should not be taken for long terms as they can cause adverse health effects. Higher than the tolerable upper limit should only be taken for a short term and only under medical supervision. Overdosage and toxicity is more likely to occur from taking too many supplements, whereas dietary intake of vitamin A is highly unlikely to cause overdosage.

Acute vitamin A toxicity (> 75000IU per day) causes the following symptoms: