HSA | FSA CARDS ARE NOW ACCEPTED

Vitamin C, SLC2A14 (GLUT14) and Your Gut Health

Vitamin C is an essential nutrient obtained from food or supplements. It acts as a powerful antioxidant, supports immune function, aids collagen production and helps with iron absorption. The SLC2A14 gene encodes GLUT14, a transporter protein that helps move the oxidized form of vitamin C into intestinal cells. Changes in SLC2A14 can alter how well vitamin C is absorbed across the gut lining, which may affect local antioxidant protection and inflammation in the gut.

Why this matters

  • Vitamin C in gut cells protects the intestinal barrier from oxidative stress and supports healthy immune responses.
  • Reduced transport of vitamin C into gut cells can lower local antioxidant capacity, which may increase susceptibility to inflammation and conditions such as inflammatory bowel disease (IBD).
  • Knowing your SLC2A14 genotype can help guide dietary choices, supplementation and monitoring to support gut health and overall well-being.

Genetic interpretations

2 effect alleles — AA (reduced absorption)

Your genotype: AA at rs2889504 (two copies of the effect allele). This variant is associated with reduced efficiency of the GLUT14 transporter, which may decrease vitamin C uptake into intestinal cells. Lower vitamin C in gut tissue can reduce local antioxidant defense and might contribute to higher risk of gut inflammation and related conditions.

Practical considerations

  • Diet: Emphasize vitamin C rich foods each day — citrus fruits, strawberries, kiwi, red and yellow bell peppers, broccoli, Brussels sprouts, tomatoes and leafy greens.
  • Supplementation: Consider a daily vitamin C supplement to help ensure adequate systemic and local levels. Divided doses (for example 250–500 mg twice daily) may improve absorption and maintain steady blood levels. Liposomal vitamin C or formulations containing ascorbic acid plus dehydroascorbic-supporting nutrients may be helpful if absorption is a concern.
  • Antioxidant support: Include other antioxidant nutrients such as vitamin E, selenium and polyphenol-rich foods (berries, green tea, colorful vegetables) to support gut antioxidant capacity.
  • Lifestyle: Avoid smoking, limit excess alcohol, manage stress and prioritize sleep to reduce oxidative burden on the gut.
  • Monitoring: Discuss with your healthcare provider whether targeted testing is appropriate, such as plasma vitamin C level and markers of inflammation if you have symptoms or a personal history of gut inflammation.
1 effect allele — AC (moderately reduced absorption)

Your genotype: AC at rs2889504 (one copy of the effect allele). This genotype is associated with moderately impaired vitamin C transport into intestinal cells. GLUT14 may work less efficiently, potentially reducing the amount of vitamin C that reaches gut tissues where it acts as an antioxidant.

Practical considerations

  • Diet: Aim for frequent servings of vitamin C rich foods throughout the day rather than a single large meal. Combine fruits and vegetables with meals to enhance overall nutrient absorption.
  • Supplementation: A moderate vitamin C supplement (for example 250–500 mg daily) can help maintain adequate status. If you have digestive symptoms or a history of IBD, discuss higher or divided dosing with your provider.
  • Antioxidant diet: Focus on whole foods rich in antioxidants and fiber to support the microbiome and reduce intestinal inflammation.
  • Lifestyle: Maintain regular physical activity, adequate sleep and stress reduction practices to support immune and gut health.
  • Monitoring: If you experience persistent gut symptoms, work with your clinician to check vitamin C status and inflammatory markers as needed.
0 effect alleles — CC (typical absorption)

Your genotype: CC at rs2889504 (no effect alleles). This genotype is associated with typical GLUT14-mediated transport of the oxidized form of vitamin C into intestinal cells, supporting efficient absorption and utilization from dietary sources.

Practical considerations

  • Diet: Continue a balanced diet with regular servings of vitamin C rich fruits and vegetables to support gut and overall health.
  • Supplementation: Most people with typical absorption can meet needs from a healthy diet. Consider a supplement only if dietary intake is low, during times of increased need, or as directed by your healthcare provider.
  • Healthy habits: Maintain a varied, antioxidant-rich diet, regular exercise, good sleep and stress management to support gut integrity and immune function.
  • Monitoring: Routine screening is generally not required for vitamin C if diet and health are typical. Discuss testing if you develop symptoms affecting nutrient intake or absorption.

Diet recommendations

Focus on whole food sources of vitamin C and supporting nutrients. Suggestions:

  • Daily: 2–3 servings of fruit that include at least one high vitamin C choice (orange, kiwi, strawberries).
  • Vegetables: Include bell peppers, broccoli, Brussels sprouts, tomatoes or leafy greens at most meals.
  • Combine vitamin C with iron-rich plant foods (legumes, spinach) to improve non-heme iron absorption.
  • Snack ideas: Bell pepper slices with hummus, fruit and yogurt, or a mixed berry and spinach smoothie.

Supplement considerations

When diet alone may be insufficient or if you have a genotype suggesting reduced absorption, supplements can help. General points:

  • Forms: Ascorbic acid is effective. Liposomal vitamin C or formulations that support dehydroascorbic acid transport may be considered if absorption concerns exist.
  • Dosing: Typical supplemental ranges are 100–500 mg daily for general support. Divided doses can maintain steady levels. Higher doses should be discussed with your clinician.
  • Safety: Vitamin C is generally well tolerated. Very high doses can cause gastrointestinal discomfort in some people and may affect certain medical conditions or medications. Review with your healthcare provider.

Lifestyle and additional strategies

  • Stop smoking and limit alcohol to reduce oxidative stress on the gut.
  • Manage stress with regular sleep, mindfulness, and moderate exercise to support gut barrier function and immune balance.
  • Support the microbiome with a fiber-rich diet and fermented foods if tolerated.
  • Maintain regular checkups with your healthcare provider and report persistent gastrointestinal symptoms promptly.

Suggested blood tests to discuss with your clinician

  • Plasma vitamin C level to assess current status when deficiency or low intake is suspected.
  • Inflammatory markers such as C-reactive protein (CRP) if there are signs of gut inflammation.
  • Complete blood count and iron studies if symptoms suggest poor absorption or anemia.

Important disclaimer

PlexusDx provides education about genetic predispositions and does not provide medical advice. This information is not a diagnosis or treatment plan. Always consult with your healthcare provider before starting or changing diet, supplements, or lifestyle strategies, especially if you have medical conditions or take medications.