BCO1 and atherosclerosis: By probing the effect of dietary β-carotene in the presence and absence of BCO1, we could dissect the relative contribution of β-carotene and its vitamin A derivatives and found that β-carotene decreases circulating cholesterol and delays atherosclerosis progression in Ldlr−/− but not in Bco1−/−Ldlr−/− mice [96].