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Understanding Vitamin A, Beta-Carotene, and the BCO1 Gene

Vitamin A is essential for vision, immune function, skin health, and cell growth. It exists in two forms in food: preformed Vitamin A found in animal products such as eggs, dairy, and oily fish, and provitamin A carotenoids like beta-carotene found in colorful fruits and vegetables. The BCO1 gene makes an enzyme that converts beta-carotene into active Vitamin A (retinol). Variations in BCO1 can reduce how efficiently your body performs that conversion. That means some people may get less usable Vitamin A from plant sources and might benefit from dietary adjustments or monitoring to maintain healthy Vitamin A levels.

How BCO1 Variants Affect Vitamin A Conversion

The single nucleotide polymorphism rs6420424 in the BCO1 gene can influence beta-carotene conversion efficiency. Your genotype at this site is reported as two effect alleles (AA), one effect allele (AG), or zero effect alleles (GG). The more effect alleles you carry, the more likely your enzyme converts beta-carotene to retinol less efficiently. Beta-carotene still provides antioxidant benefits regardless of conversion, but differences in conversion can influence whether plant sources alone meet your Vitamin A needs.

Two effect alleles (AA) — decreased conversion

If you have the AA genotype for rs6420424, you carry two copies of the effect allele. This genotype is associated with decreased beta-carotene conversion to the active form of Vitamin A. The BCO1 gene produces an enzyme that converts beta-carotene from plant foods into active Vitamin A (retinol). With two copies of the effect allele, your BCO1 enzyme may be less active, meaning your body might not efficiently convert beta-carotene from colorful vegetables and fruits into usable Vitamin A. While beta-carotene still provides antioxidant benefits, you may benefit from including direct sources of preformed Vitamin A in your diet, such as eggs, dairy, and oily fish. Pairing beta-carotene-rich foods with healthy fats and cooking vegetables can also enhance absorption and availability.

One effect allele (AG) — likely decreased conversion

If you have the AG genotype for rs6420424, you carry one copy of the effect allele. This genotype is associated with likely decreased beta-carotene conversion to the active form of Vitamin A. The BCO1 gene produces an enzyme that converts beta-carotene from plant foods into active Vitamin A (retinol) in your small intestine. With one copy of the effect allele, your BCO1 enzyme may be less efficient at this conversion, meaning you might not get as much usable Vitamin A from beta-carotene-rich vegetables and fruits compared to others. While beta-carotene still provides antioxidant benefits, your body's ability to transform it into Vitamin A may be somewhat reduced. To support adequate Vitamin A levels, consider including preformed Vitamin A sources like eggs, dairy, and oily fish in your diet, as these don't require conversion. Continue eating colorful vegetables like carrots and sweet potatoes, and pair them with healthy fats like olive oil or avocado to enhance absorption. Cooking these vegetables can also improve beta-carotene availability.

Zero effect alleles (GG) — typical conversion

If you have the GG genotype for rs6420424, you carry two copies of the non-effect allele. The GG genotype is associated with typical beta-carotene conversion efficiency. Your BCO1 gene produces the enzyme that effectively converts beta-carotene from plant foods into active Vitamin A (retinol). This means your body can efficiently utilize beta-carotene from colorful fruits and vegetables like carrots, sweet potatoes, and spinach to meet your Vitamin A needs. You can obtain Vitamin A from both plant sources (beta-carotene) and animal sources (preformed Vitamin A from eggs, dairy, and fish). Continue eating a balanced, varied diet rich in both beta-carotene-containing vegetables and animal-based Vitamin A sources to support healthy vision, immune function, and overall well-being.

Dietary Guidance

  • Include both plant and animal sources of Vitamin A. If your conversion may be reduced, emphasize preformed Vitamin A foods such as eggs, full-fat dairy products in moderation, liver (occasionally), and oily fish like salmon and mackerel.
  • Keep colorful, beta-carotene-rich vegetables on your plate. Carrots, sweet potatoes, pumpkin, butternut squash, spinach, kale, and red peppers are all excellent sources of provitamin A.
  • Eat beta-carotene foods with healthy fats to boost absorption. Add a drizzle of olive oil, a few slices of avocado, nuts, or seeds to vegetable dishes.
  • Cook some vegetables. Light cooking increases the bioavailability of beta-carotene from many plant foods. Roasting, steaming, or sautéing can improve nutrient release and absorption.
  • Balance portion sizes. Vitamin A is fat-soluble, so avoid excessive intake of preformed Vitamin A supplements without medical supervision due to toxicity risk.

Supplement Considerations

  • Discuss supplementation with your healthcare provider before starting. PlexusDx does not provide medical advice. Your provider can assess whether a Vitamin A supplement is appropriate, which form to use, and the correct dose.
  • Prefer provitamin A from dietary sources first. For individuals with decreased conversion, preformed Vitamin A or mixed carotenoid supplements may be recommended by a clinician if diet alone is insufficient.
  • Avoid high-dose preformed Vitamin A supplements during pregnancy unless prescribed, because excess preformed Vitamin A can be harmful during fetal development.

Lifestyle and Monitoring

  • Watch for signs of low Vitamin A. Symptoms can include night vision trouble, dry eyes, dry skin, and frequent infections. These signs warrant evaluation by a healthcare provider.
  • Consider periodic blood testing if you have risk factors or symptoms. Your clinician may check serum retinol or related markers when there are concerns about Vitamin A status.
  • Use a balanced approach to diet rather than relying solely on supplements. A varied eating pattern supports not only Vitamin A status but many other nutrients important for overall health.

When to Talk with Your Healthcare Provider

  • If you have persistent vision changes, night blindness, chronic dryness of eyes or skin, or frequent infections.
  • If you are pregnant, planning pregnancy, or breastfeeding and are considering Vitamin A supplements.
  • If you follow a strictly vegan or vegetarian diet and are concerned about meeting Vitamin A needs through diet alone.
  • If you are on medications or have medical conditions that affect nutrient absorption or metabolism.

Summary

Your BCO1 genotype can influence how well your body converts plant-based beta-carotene into active Vitamin A. If your genetic result indicates decreased conversion, you can support healthy Vitamin A levels by adding preformed Vitamin A foods, continuing to eat beta-carotene-rich vegetables with healthy fats, and considering light cooking methods to improve absorption. Discuss testing or supplementation with your healthcare provider to ensure safe and personalized care.

Important: PlexusDx does not provide medical advice. The information in this article is educational and based on genetic predispositions. Always consult with your healthcare provider before making changes to your diet, starting supplements, or if you have health concerns.