Is it safe to take vitamin A supplements?

From the Guidelines

Taking vitamin A supplements can be safe when used as directed, but caution is needed to avoid potential harms, particularly for pregnant women, individuals with liver disease, and those taking certain medications. For most healthy adults, vitamin A supplements are safe at the recommended dietary allowance (RDA) of 700-900 micrograms (2,300-3,000 IU) daily 1. However, taking high doses over 10,000 IU daily for extended periods can be toxic and cause serious side effects including liver damage, bone abnormalities, increased pressure in the brain, and birth defects.

Key Considerations

• Pregnant women should be especially careful and avoid supplements containing more than 5,000 IU of preformed vitamin A (retinol) due to potential birth defect risks 1.
• People with liver disease, those who drink alcohol heavily, or those taking certain medications should consult their healthcare provider before taking vitamin A supplements.
• Most people get adequate vitamin A from their diet through foods like sweet potatoes, carrots, spinach, liver, and dairy products, making supplements unnecessary unless specifically recommended by a healthcare provider for a deficiency.
• If you choose to supplement, select products from reputable manufacturers and stay within recommended dosage limits.

Special Populations

• For individuals with cystic fibrosis, vitamin A supplementation may be necessary to prevent deficiency, but the dose should be determined based on serum values and supplement form, with careful consideration of the risk of hypervitaminosis A 1.
• The normal range of serum retinol concentrations for healthy people should be aimed for, with assessment of vitamin A intake and blood levels before conception or early in pregnancy.

General Guidance

• Always consult with a healthcare provider before taking vitamin A supplements, especially if you have any underlying medical conditions or are taking medications.
• Be aware of the potential harms of excessive vitamin A intake, including liver damage, bone abnormalities, and birth defects.
• Prioritize a balanced diet rich in fruits, vegetables, whole grains, and lean protein sources to meet your nutritional needs, rather than relying on supplements.

From the FDA Drug Label

Warnings For external use only. When using this product avoid contact with eyes. If contact occurs, rinse thoroughly with water. Stop use and ask doctor if condition worsens or symptoms last more than 7 days. If swallowed, get medical help or contact a poison control center immediately. Do not use on deep or puncture wounds, animal bites or serious burns. Keep out of reach of children. If swallowed, get medical help or contact a Poison Control Center right away (1-800-222-1222).

The FDA drug label does not answer the question.

From the Research

Safety of Vitamin A Supplements

• The safety of taking vitamin A supplements is a concern, as excessive intake can lead to toxicity 2.
• Studies have shown that consumption of 25,000-50,000 IU/d for periods of several months or more can produce multiple adverse effects, including birth defects in pregnant women 2.
• Certain groups, such as children and pregnant women, are especially vulnerable to vitamin A toxicity, with adverse effects occurring at lower intakes 2.
• The regulation of vitamin A supplements is limited, and they are not subject to the same labeling rules as prescription medications, making it difficult for consumers to assess the risks 3.

Risks and Precautions

• High-dose vitamin A supplements can cause birth defects, and the maternal dose threshold for birth defects cannot be identified from present data 2.
• Label analysis is key to educating patients about the risks of vitamin A-containing supplements, and more FDA oversight of the dietary supplement industry is needed 3.
• The bioconversion of traditional dietary sources of β-carotene to vitamin A is much less efficient than previously supposed, and high intake of β-carotene has been linked to an increased risk of lung cancer in high-risk individuals 4.

Importance of Vitamin A

• Vitamin A is an essential nutrient required for normal organogenesis, immune competence, tissue differentiation, and the visual cycle 4.
• Deficiency in vitamin A is widespread throughout the developing world and is responsible for a million or more instances of unnecessary death and blindness each year 4.
• However, there is no evidence that taking vitamin supplements without medical indication improves the health of people with a varied diet, and the fact that vitamins can be toxic when taken in overdose is not common knowledge 5.