Vitamin A is safe for most people when taken in recommended amounts. Large amounts of vitamin A can cause headaches, blurred vision, dizziness, loss of appetite, nausea, vomiting, bone pain, benign yellow-orange skin, and hair loss. If large amounts are taken for a long time, you may experience dry, scaly, and peeling skin, tiredness, irritability, psychiatric changes, depression, vomiting, fever, and coma or even death.
High doses of vitamin A can also harm the liver. People who drink alcohol on a regular basis or have liver diseases or are take medications that can affect the liver should consult a health care professional before taking a vitamin A supplement.
People who smoke are at an increased risk of lung cancer if taking vitamin A (specifically beta-carotene). Consult a health care professional if you are currently smoking or recently quit smoking before taking vitamin A supplement.
Avoid taking vitamin A if you have:
- poor fat absorption
- an intestinal infection
- liver disease
Vitamin A is safe to use if you are pregnant or breast-feeding, provided that you do not take more than the recommended amount. High intake of retinol during pregnancy can cause birth defects.
Vitamin A can interact with certain medications, including selected antibiotics (e.g., tetracyclines), some acne products, bile acid sequestrants, blood-pressure-lowering medications, and agents that increase the risk of bleeding (e.g., warfarin). Speak to a pharmacist if you are concerned about this.
Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.