Beta-carotene to vitamin A conversion (BCO1)

BCO1 is the enzyme that turns beta-carotene (the orange pigment in carrots and leafy greens) into active vitamin A. A common variant lowers its activity, so carriers convert plant beta-carotene into vitamin A less efficiently.

Possible results

Efficient converter (BCO1). You have the efficient version of BCO1, so your body readily turns plant beta-carotene (from carrots, sweet potato, leafy greens) into active vitamin A. A normal varied diet covers your vitamin A well.

Somewhat reduced conversion. You carry one copy of the lower-activity BCO1 variant, so you convert plant beta-carotene into vitamin A a bit less efficiently. Eating a range of vitamin-A sources (including some from animal foods or fortified items, if you eat them) helps cover the gap.

Reduced converter (BCO1). You have two copies of the lower-activity BCO1 variant, so you turn plant beta-carotene into active vitamin A noticeably less efficiently. If you rely mostly on plant sources, getting some preformed vitamin A (dairy, eggs, fish, or fortified foods) or simply more carotenoid-rich produce helps ensure enough.

Related

Adult lactose digestion · Folate metabolism (MTHFR gene) · HDL cholesterol · LDL cholesterol · Secretor status (norovirus resistance & B12) · Sweet tooth / carbohydrate preference (FGF21) · Triglycerides