Why supplement?
Supports normal vision
Vitamin A is a core part of rhodopsin and is especially needed for dim-light vision. The diet supplies it from animal liver, egg yolk, and fortified dairy; plant sources rely on carotenoids converting to retinol. Supplements should distinguish retinol/RAE labeling. Put the use on everyday vision and mucosal nutrition.
Supports immune function
Vitamin A takes part in epithelial-barrier integrity and immune-cell differentiation; mucosal defense is often linked to it. Daily intake can come from preformed retinol or β-carotene foods. Read supplements in RAE. The focus is barrier and immune nutrition, not chasing ever-higher doses.
How to take it
Calculate from the labeled retinol/RAE units; do not mix IU and mcg.
How oftenStay near the recommended daily intake; do not raise the dose on your own long term.
What to watch
Cautions
Pregnant people should not self-start high-dose preformed vitamin A; excess can harm the fetus.
People with liver disease or taking vitamin A medicines should ask a doctor first.
· Nausea or headache (high doses)
· Dry skin (long-term high doses)
· Chronic excess can injure the liver and raise intracranial pressure.
Long-term dependenceNot addictive; fat-soluble vitamins can be stored, so high long-term doses carry toxicity risk.