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Vitamin B6 and Your Genes: How ALPL Affects B6 Processing

Vitamin B6 is a water soluble vitamin that supports more than 100 enzyme reactions across the body. It plays important roles in energy metabolism, brain and nervous system function, immune health, red blood cell formation, and mood regulation. The ALPL gene makes tissue nonspecific alkaline phosphatase, or TNSALP, an enzyme that helps convert the active form of Vitamin B6, pyridoxal 5 phosphate or PLP, into the form cells can readily use.

Some people carry genetic variations in ALPL that can change how well the enzyme works. These variations may slightly lower circulating Vitamin B6 levels, even with a normal diet. This report explains what the rs1697421 variant means for your Vitamin B6 handling and offers food, supplement, testing, and lifestyle suggestions to help keep your B6 status in a healthy range.

How genetics can affect Vitamin B6

If the ALPL enzyme is less efficient due to genetic variants, the conversion and cellular uptake of B6 may be reduced. Because Vitamin B6 is water soluble and not stored in large amounts, regular intake from food is important. Small changes in processing can lead to lower circulating PLP, which can have subtle effects on energy, mood, immune response, and other B6 dependent processes.

Everyday actions to support Vitamin B6 status

  • Eat B6 rich foods: poultry, fish, potatoes, chickpeas, bananas, fortified cereals, organ meats, and some whole grains.
  • Balance meals: pair B6 containing proteins with complex carbohydrates and vegetables to improve overall nutrient absorption.
  • Consider routine intake: because B6 is water soluble, aim to include B6 sources regularly rather than relying on occasional large servings.
  • Limit alcohol: excessive alcohol can impair B6 metabolism and increase loss.
  • Avoid unnecessary high dose supplements: much more B6 than needed can cause sensory neuropathy with chronic very high doses.

Genetic interpretation

Two effect alleles (TT) — slightly decreased Vitamin B6 levels

If your genotype is TT at rs1697421 you carry two copies of the effect allele. This genotype is associated with a modest reduction in circulating Vitamin B6. Variations in ALPL may reduce how efficiently TNSALP converts PLP into the form cells use. While this does not mean you will have a clinical deficiency, your body may find it harder to maintain optimal B6 status compared to people without this variant.

Actions to support B6:

  • Prioritize daily intake of B6 rich foods: chicken, salmon, tuna, potatoes, chickpeas, bananas, fortified cereals, and liver in small amounts if acceptable.
  • Consider a moderate B6 containing multivitamin if your diet is inconsistent. Look for products that provide close to the RDA rather than megadoses.
  • Discuss testing with your provider. A plasma PLP test can measure B6 status if symptoms or clinical suspicion exist.
  • Monitor alcohol intake and certain medications that can lower B6 status, such as isoniazid or some anticonvulsants, with your healthcare provider.
One effect allele (CT) — slightly decreased Vitamin B6 levels

If your genotype is CT at rs1697421 you carry one copy of the effect allele. This genotype is associated with a slight reduction in Vitamin B6 processing compared to people without the variant. The TNSALP enzyme may have a somewhat reduced capacity to convert PLP for cellular use.

Actions to support B6:

  • Include B6 rich foods regularly: poultry, fish, potatoes, chickpeas, bananas, fortified cereals, nuts, and seeds.
  • If your diet is limited by preference or availability, consider a standard multivitamin that supplies the recommended daily allowance of B6 rather than a high dose supplement.
  • If you notice symptoms consistent with low B6 such as fatigue, irritability, or unusual numbness, discuss testing for plasma PLP with your healthcare provider.
  • Keep alcohol and smoking low as both can influence B6 use and status.
No effect alleles (CC) — typical Vitamin B6 processing

If your genotype is CC at rs1697421 you carry two copies of the non effect allele. This pattern is associated with typical ALPL function and normal processing of Vitamin B6. Your TNSALP enzyme should convert PLP to the cellular form effectively, and you are not genetically predisposed to lower B6 levels from this variant.

Actions to support B6:

  • Maintain a balanced diet that includes B6 rich foods: poultry, fish, potatoes, chickpeas, bananas, and fortified cereals.
  • Follow general dietary recommendations. The RDA for adults under 50 is around 1.3 mg daily. Individual needs may vary with age, pregnancy, and health conditions.
  • Reserve supplementation for times of increased need or when diet is insufficient. Avoid chronic high dose supplementation unless supervised by a healthcare provider.

Supplement guidance

Supplements can help if dietary intake is low or if testing shows low PLP. Consider these points before starting a supplement:

  • Choose supplements that provide near the recommended daily intake for your age and life stage rather than large pharmacologic doses.
  • Typical multivitamins or B complex supplements often contain 1.3 to 2 mg of Vitamin B6, which is suitable for most adults.
  • Avoid chronic high dose B6 above 100 mg daily without medical supervision because long term very high intake has been linked to nerve symptoms.
  • If you take medications or have medical conditions, check with your provider before starting supplements.

When to consider testing and medical review

  • Discuss PLP blood testing with your healthcare provider if you have symptoms that could relate to low B6 such as unexplained fatigue, anemia, mood changes, or neuropathy.
  • Ask about medication interactions that may lower B6 and whether adjustments or monitoring are appropriate.
  • If you are pregnant, breastfeeding, or managing chronic illness, work with your provider to set nutrition and supplementation goals.

Important disclaimer

PlexusDx provides educational information about genetic predispositions. This content is not medical advice. Always consult with your healthcare provider before making changes to your diet, starting supplements, or pursuing clinical testing. Your provider can interpret genetic results in the context of your health history, medications, and current symptoms.