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Beta-Carotene Conversion

Your result, the DNA positions behind it, and what the research says.

6/10 confidence.

About Beta-Carotene Conversion

Vitamin A comes in two forms. Animal foods supply it ready-made as retinol; plants supply beta-carotene, which the body has to cut in half to make retinol. One enzyme, BCO1, does that cutting. Two common changes in it each lower its activity, and carrying both lowers it a great deal more than either alone. People with low converter activity get less vitamin A from the same carrot than people with high activity, which is why beta-carotene intake and vitamin A status can come apart.

Good to know: Plant beta-carotene must be converted; animal vitamin A does not. The two changes together reduce enzyme activity far more than either alone. Low converter activity is common in European ancestry, not unusual.

Fun fact: Eating an extreme amount of carrots can turn skin faintly orange, because unconverted beta-carotene collects in the outermost keratin layer of the skin, showing first on the palms and soles.

Discovery: The two reduced-activity BCO1 variants and their combined effect were characterized in 2009.

The Variants

The 2 positions this trait reads

Gene: BCO1

rs12934922 Arg267Ser (R267S) - reduced-activity variant

rs7501331 Ala379Val (A379V) - reduced-activity variant

Location: Chr 16:81,280,891

dbSNP rs7501331

The studies

Two common single nucleotide polymorphisms in the gene encoding beta-carotene 15,15'-monoxygenase alter beta-carotene metabolism in female volunteers (Leung WC et al., FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 2009)

Other lifestyle traits

Carotenoid Levels: A change in the master regulator of fat cells, linked to how much provitamin A carotenoid is stored in fat tissue.

Calcium Levels: A change on chromosome 3 linked to the level of calcium circulating in blood.

Magnesium Levels: A change in a mucin gene expressed in the kidney, linked to circulating magnesium in large studies.

Back to All Traits

Content updated September 2026.

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