Can vitamin A be harmful? (The upper limits for preformed vitamin A in IU)

https://ods.od.nih.gov/factsheets/VitaminA-Consumer/

Can vitamin A be harmful?

Yes, high intakes of some forms of vitamin A can be harmful.

Getting too much preformed vitamin A (usually from supplements or certain medicines) can cause dizziness, nausea, headaches, coma, and even death. High intakes of preformed vitamin A in pregnant women can also cause birth defects in their babies. Women who might be pregnant should not take high doses of vitamin A supplements.

Consuming high amounts of beta-carotene or other forms of provitamin A can turn the skin yellow-orange, but this condition is harmless. High intakes of beta-carotene do not cause birth defects or the other more serious effects caused by getting too much preformed vitamin A.

The upper limits for preformed vitamin A in IU are listed below. These levels do not apply to people who are taking vitamin A for medical reasons under the care of a doctor. Upper limits for beta-carotene and other forms of provitamin A have not been established.

Life Stage	Upper Limit
Birth to 12 months	2,000 IU
Children 1–3 years	2,000 IU
Children 4–8 years	3,000 IU
Children 9–13 years	5,667 IU
Teens 14–18 years	9,333 IU
Adults 19 years and older	10,000 IU