BCMO1 Gene.
Beta-Carotene Oxygenase 1
The enzyme that converts beta-carotene to vitamin A. When it's slow, plants alone can't meet your vitamin A needs.
What BCMO1 does.
BCMO1 cleaves beta-carotene into two molecules of retinal (vitamin A). This is how your body gets vitamin A from orange and green vegetables.
The conversion:
Beta-carotene → 2x Retinal (vitamin A)
(BCMO1 enzyme, in intestine and liver)
Good converters
- • Can meet vitamin A needs from plants
- • Efficiently use carrots, sweet potatoes
- • Don't accumulate carotenoids
- • Vegetarian/vegan diets work fine
Poor converters
- • Up to 70% reduction in conversion
- • Need preformed vitamin A (retinol)
- • May accumulate carotenoids (yellow skin)
- • Plant-based diets may cause deficiency
Common variants.
A379V (rs7501331)
Reduces conversion ~32% per T alleleOne of the most impactful variants. Two copies can reduce conversion by ~50%.
Frequency: T allele: ~40-45% in European populations
R267S (rs12934922)
Reduces conversion ~32% per T alleleOften inherited together with A379V. Combined effect is significant.
Frequency: T allele: ~40-45% in European populations
The combined effect
People with two copies of both variants (relatively common) may have only 30% of normal conversion capacity. This isn't rare—it affects a significant portion of the population.
Signs of poor conversion.
These may indicate you're not converting beta-carotene efficiently.
- ✓Pale skin even after eating lots of carrots/sweet potatoes
- ✓Carotenemia (yellow/orange palms) from unprocessed carotenoids
- ✓Night blindness or poor dark adaptation
- ✓Dry skin, eyes, or mucous membranes
- ✓Frequent infections (vitamin A supports immunity)
- ✓Thyroid issues (vitamin A needed for thyroid hormone receptors)
- ✓Poor response to plant-based vitamin A supplementation
The vegetarian question.
Can you get enough vitamin A from plants? It depends on your BCMO1 genes.
Sources of vitamin A:
Beta-carotene (provitamin A)
- • Carrots, sweet potatoes
- • Dark leafy greens
- • Squash, pumpkin
- • Requires BCMO1 conversion
Retinol (preformed vitamin A)
- • Liver (highest source)
- • Egg yolks
- • Dairy (if fortified)
- • Fish/cod liver oil
- • No conversion needed
"If you have BCMO1 variants, preformed vitamin A from animal foods may be necessary—plants alone won't cut it."
Genes don't act alone.
BCMO1 doesn't determine your fate. It reveals where the system might need support.
Where it matters
BCMO1 is most active in the intestinal mucosa and liver. Conversion happens primarily during absorption.
Expression depends on
- • Nutrient availability
- • Sunlight exposure
- • Toxin burden
- • Cell turnover rate
- • Age and hormonal status
SNPs are throttles, not defects
Genetic variants often slow down pathways to protect the system from overwhelm. They reveal where you need to go slower, not that you're broken.
The real question
Not "what does this gene do?" but "what is this pathway already struggling with that makes this gene relevant?"
Related patterns
"Genes don't cause outcomes. They reveal where the system is already under pressure."
Support strategies.
Include preformed vitamin A
If you have BCMO1 variants, include sources of preformed vitamin A: liver (best source), egg yolks, grass-fed dairy, cod liver oil.
Eat carotenoids with fat
Beta-carotene is fat-soluble. Absorption increases dramatically when eaten with fat. Don't eat dry carrots—add butter or olive oil.
Consider retinyl palmitate supplements
If diet alone isn't enough, preformed vitamin A supplements bypass the conversion step. Be careful with dosing—vitamin A can be toxic in excess.
Support thyroid function
BCMO1 expression requires thyroid hormone. Hypothyroidism reduces conversion further. Address thyroid issues to optimize BCMO1 function.
Ensure adequate zinc and iron
Both zinc and iron are needed for vitamin A metabolism. Deficiency in either can compound the problem.
Not everyone can live on carrots alone.
BCMO1 variants are common. If you're not converting beta-carotene efficiently, preformed vitamin A may be essential.