Yes, retinol is Vitamin A. I think I've seen this study discussed elsewhere, but can't remember any of it. Will search later.
Note that Vitamins A & D are sympathetic. Increasing consumption of one increases one's need for the other. Chris Masterjohn has a bit to say about this.
Agree with merl - retinol is best taken naturally. Liver and shellfish are very good sources, as is grass-fed dairy
Four years Primal with influences from Jaminet & Shanahan and a focus on being anti-inflammatory. Using Primal to treat CVD and prevent stents from blocking free of drugs.
Eat creatures nose-to-tail (animal, fowl, fish, crustacea, molluscs), a large variety of vegetables (raw, cooked and fermented, including safe starches), dairy (cheese & yoghurt), occasional fruit, cocoa, turmeric & red wine