lists 3,000 mcg RAE as the adult tolerable upper intake level for preformed vitamin A, and excessive intake can lead to toxicity.
High intake over time may affect the liver and cause symptoms such as headache, dizziness, nausea, skin changes, bone pain, or more serious complications. People should be especially careful with high-dose vitamin A capsules, “skin” supplements, and multivitamins that already contain vitamin A.
2. Vitamin D
Vitamin D supports bones, muscles, and immune function, but high-dose vitamin D can become toxic. Vitamin D toxicity usually happens from
