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Last reviewed: May 12, 2026 Last updated: May 12, 2026

Written by: Jay Hastings , CEO of PlexusDx

Jay Hastings is the CEO of PlexusDx, a precision health company focused on genetic testing, blood biomarker insights, and personalized wellness recommendations. He has more than 20 years of experience across healthcare innovation, genomics, laboratory operations, healthcare investing, and strategic finance. His work has included scaling healthcare startups, leading CLIA lab integrations, and helping expand consumer access to precision health tools.

Medically reviewed by: Jayden Lee, PharmD, EMBA

Jayden Lee, PharmD, EMBA, is the PlexusDx Medical Science Liaison with a PharmD and MBA specializing in pharmacogenomics and clinical product development, with a proven ability to bridge the gap between genomic research and practical patient outcomes. Dr. Lee has more than 10 years of professional experience in clinical pharmacy, academia, and research.

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.

If this genetic variant is present in your PlexusDx results, the following tests and reports are commonly used to explore it further:

🧬 Genetic Tests:

🧪 Blood Tests:

📄 Genetic Report:

Frequently Asked Questions About Vitamin A and BCO1 rs6564851

How does the BCO1 gene affect conversion of beta-carotene into vitamin A?

The BCO1 gene provides instructions for beta-carotene oxygenase 1, the enzyme that converts beta-carotene (a provitamin A carotenoid from fruits and vegetables) into active vitamin A. Genetic variations in BCO1 can change how efficiently your body completes this conversion, affecting how much active vitamin A your diet provides.

What dietary changes should I make if I have reduced BCO1 conversion (rs6564851 effect allele)?

If your rs6564851 result suggests decreased BCO1 efficiency (GT or GG), plant-based beta-carotene may provide less active vitamin A than expected. Focus on balancing carotenoid-rich vegetables with preformed vitamin A sources (such as eggs, dairy, oily fish, fortified foods, and—if appropriate—moderate liver in place of relying on plants alone). Also pair carotenoid vegetables with healthy fats (olive oil, avocado, nuts, seeds, coconut, or full-fat dairy) and consider lightly cooking or roasting vegetables to improve absorption.

Are vitamin A supplements recommended for BCO1-related conversion differences, and how can I use them safely?

Supplements may be considered if dietary intake is limited or if conversion is reduced, but safety matters because preformed vitamin A can accumulate and become toxic—especially in pregnancy. Carotenoid supplements may not convert to retinol as efficiently in people with reduced BCO1 activity, so clinicians may recommend different formulations based on genotype and needs. Always consult your healthcare provider before starting vitamin A supplements, and avoid high-dose preformed vitamin A unless specifically directed.

What tests can help me learn more about Vitamin A and BCO1 rs6564851?

The Optimal Diet and Weight Loss Genetic Test delivers over 295 genetic insights related to nutrition response, body composition, metabolism, and fitness. The Diet and Nutrition Genetic Report translates your results into personalized, actionable guidance. Your healthcare provider can also recommend targeted blood tests based on your specific pathway results and health history to complement your genetic insights with current biomarker data.

Medical and Editorial Standards

Medical review process: This article was reviewed for medical accuracy, scientific clarity, evidence alignment, and appropriate discussion of genetics, medications, supplements, biomarkers, and health-related claims.

Sources and evidence: PlexusDx educational content is developed using peer-reviewed research, clinical literature, reputable medical references, and, where applicable, public health or regulatory guidance. References are included at the end of the article when scientific, medical, or health-related claims are discussed.

Commercial transparency: PlexusDx offers genetic testing, blood biomarker testing, personalized supplement recommendations, and related precision wellness services. Product mentions are intended to help readers understand available options and should not be interpreted as medical advice.

Important disclaimer: PlexusDx educational content is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about medications, supplements, genetic testing, lab testing, or health-related care.