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Vitamin A, BCO1, and Your Nutrition: How Genetics Can Affect Conversion of Beta-Carotene

Vitamin A is essential for healthy vision, immune function, skin integrity, and cell growth. You get vitamin A from two dietary forms: preformed vitamin A (retinol) found in animal-based foods, and provitamin A carotenoids such as beta-carotene found in colorful fruits and vegetables. The BCO1 gene makes the enzyme beta-carotene oxygenase 1, which converts beta-carotene into the active form of vitamin A. Variations in BCO1 can change how efficiently your body performs that conversion.

How BCO1 Genetic Variants Matter

Not everyone converts beta-carotene into retinol at the same rate. Some people have genetic variants in BCO1 that reduce enzyme efficiency. If your conversion is less efficient, plant-based beta-carotene will yield less active vitamin A for your body, so dietary choices and absorption strategies become more important.

Two effect alleles (GG for rs6564851): decreased conversion

If your genotype is GG at rs6564851, you carry two copies of the effect allele and are likely to have reduced ability to convert beta-carotene into active vitamin A. Your BCO1 enzyme works less efficiently, so relying only on plant sources of beta-carotene may not deliver enough vitamin A.

  • Diet: Include regular servings of preformed vitamin A from animal sources such as liver (in moderation), dairy, eggs, oily fish, and fortified foods. Continue to eat beta-carotene-rich vegetables like carrots, sweet potatoes, but always pair them with a source of healthy fat to improve absorption.
  • Supplements: Discuss with your healthcare provider whether a supplement containing preformed vitamin A (retinyl palmitate or retinyl acetate) or a mixed carotenoid supplement is appropriate. Avoid excessive vitamin A intake, especially from supplements, because high doses of preformed vitamin A can be toxic.
  • Lifestyle and absorption: Eat colorful vegetables with fats such as olive oil, avocado, nuts, or full-fat dairy to maximize carotenoid absorption. Avoid very low-fat diets immediately around meals that supply carotenoids.
  • Monitoring: Consider periodic checks with your clinician if you or your provider are concerned about symptoms of low vitamin A (night vision problems, dry eyes, frequent infections) or if you follow a restrictive diet. Blood tests for vitamin A status or related markers can be arranged by your healthcare provider.
One effect allele (GT for rs6564851): likely decreased conversion

If your genotype is GT at rs6564851, you carry one copy of the effect allele and may have somewhat reduced beta-carotene to vitamin A conversion compared to individuals without the effect allele. Conversion is typically still possible but may be less efficient.

  • Diet: Aim for a balanced mix of preformed vitamin A sources and beta-carotene-rich plant foods. Include eggs, dairy, oily fish, and moderate portions of liver if appropriate, along with colorful vegetables like carrots, pumpkin, butternut squash, and dark leafy greens.
  • Meal tips: Pair plant sources of beta-carotene with healthy fats at meals. Lightly cooking some carotenoid-rich vegetables can increase bioavailability when combined with fat.
  • Supplements: If dietary intake is limited (for example, in certain vegetarian or vegan diets) talk with your healthcare provider about whether a supplement is needed and which formulation is safest for you.
  • Monitoring: Be aware of changes in vision, skin, or immune health and consult your provider if symptoms arise. Targeted testing can be considered when there is clinical concern.
Zero effect alleles (TT for rs6564851): typical conversion

If your genotype is TT at rs6564851, you carry two copies of the non-effect allele and are likely to convert beta-carotene into active vitamin A at typical efficiency. You can obtain vitamin A from both plant-based and animal-based sources effectively.

  • Diet: Continue enjoying a variety of colorful fruits and vegetables along with regular sources of dietary fat to maximize carotenoid absorption. Incorporate eggs, dairy, fish, and occasional organ meats if desired for additional preformed vitamin A.
  • Meal tips: Eating vegetables such as carrots, sweet potatoes, and dark leafy greens cooked or lightly steamed with a fat source will help you absorb beta-carotene.
  • Supplements: Most people with normal conversion do not need vitamin A supplements if they maintain a balanced diet. Only take supplements under the guidance of a healthcare professional.
  • Monitoring: Routine dietary monitoring is usually sufficient. Seek medical evaluation if you experience symptoms like night blindness or frequent infections.

Practical Food and Meal Strategies

  • Balance carotenoid-rich plant foods and preformed vitamin A sources. If you eat little or no animal products, pay special attention to maximizing carotenoid absorption and discuss supplementation with your clinician.
  • Always include healthy fats at meals containing carotenoid-rich vegetables: olive oil, avocado, nuts, seeds, coconut, or full-fat dairy improve absorption.
  • Cooking can increase carotenoid bioavailability. Lightly steaming, roasting, or sautéing vegetables often makes beta-carotene more accessible than raw consumption, especially when eaten with fat.
  • Use moderate portions of liver occasionally if appropriate for you, because liver is rich in preformed vitamin A. Do not consume high amounts of liver regularly, and avoid large supplemental doses of preformed vitamin A without medical supervision.

Supplement Guidance and Safety

Supplements can help when dietary intake is insufficient or when genetic conversion is reduced, but there are important safety considerations. Preformed vitamin A can accumulate and become toxic at high doses, especially during pregnancy. Carotenoid supplements are not converted into retinol with the same efficiency in people with reduced BCO1 activity, so a clinician may recommend different formulations depending on your needs and genotype. Always consult your healthcare provider before starting any vitamin A supplement.

When to Talk with Your Healthcare Provider

  • If you follow a restrictive diet (vegan, very low-fat), since plant-based carotenoids may not meet needs if conversion is reduced.
  • If you notice symptoms such as night vision difficulties, persistent dry eyes, frequent infections, or skin changes.
  • If you are pregnant or planning pregnancy, because vitamin A needs and risks change during pregnancy and supplementation decisions should be clinician-led.
  • If you are considering high-dose supplements or have liver disease, as excess preformed vitamin A can cause harm.

Monitoring and Testing

Your healthcare provider can order tests or assessments if there is concern about vitamin A status. Clinical evaluation and targeted laboratory testing can help guide whether dietary adjustments or supplements are needed. Regular monitoring is especially important if you are using supplements or have health conditions that affect absorption or liver storage of fat-soluble vitamins.

PlexusDx does not provide medical advice. This information is educational and intended to help you understand how genetic variations in BCO1 can influence your ability to convert beta-carotene to active vitamin A. Always consult your healthcare provider before making changes to your diet, starting supplements, or interpreting clinical test results.