Vitamin A is an interesting subject.

Recently I learned that there are different forms of vitamin A. Notably, one finds carotenoids in plants. For example, carrots are high in beta-carotene.

Retinol and Retinyl are found in animal sources.

Our bodies need retinol Some people lack the ability to convert carotenes into retinol.

So, a person might consume a large amount of carotene but still have a retinol deficiency.