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Vitamin C and Your Genes: How SLC23A2 Affects Vitamin C Levels and What You Can Do

Vitamin C is an essential nutrient that supports immune function, helps form collagen for healthy skin and tissues, acts as a powerful antioxidant, and improves iron absorption. Because the body cannot produce Vitamin C, you need to get it through food every day. The SLC23A2 gene makes the SVCT2 protein, a transporter that moves Vitamin C from the blood into cells. Variations in SLC23A2 can affect how Vitamin C is transported, distributed, and ultimately how much stays in the bloodstream.

This article explains what different genotypes at rs6133175 in SLC23A2 mean for circulating Vitamin C, and offers practical diet, supplement, and lifestyle suggestions to help you maintain optimal Vitamin C status. PlexusDx does not provide medical advice. Use this information to learn about genetic predispositions and discuss any health decisions with your healthcare provider.

How SLC23A2 and SVCT2 Work

SVCT2 is a transporter protein located in cell membranes that moves the active, reduced form of Vitamin C (ascorbic acid) from blood into cells throughout the body, including the brain, heart, and connective tissues. Transport efficiency influences how much Vitamin C is available inside cells and how much remains circulating in plasma. Differences in transporter function can shift the balance between cellular uptake and circulating levels.

Practical Implications

  • Even if genetics suggest higher plasma Vitamin C, you still must eat Vitamin C daily because your body does not make it.
  • Dietary intake, smoking, alcohol use, chronic illness, and certain medications also affect Vitamin C status and may override small genetic effects.
  • Monitoring diet and simple blood tests can confirm whether your Vitamin C intake is adequate for your needs.

Daily Vitamin C Goals

  • Focus on a diet rich in fruits and vegetables: citrus, strawberries, kiwi, bell peppers, broccoli, Brussels sprouts, and leafy greens.
  • Include a variety of colors and raw or lightly cooked produce to preserve Vitamin C, which is heat sensitive.
  • Consider food combinations that enhance iron absorption, such as pairing Vitamin C sources with plant-based iron sources.

Genetic Interpretations

2 effect alleles (GG) — Higher plasma Vitamin C

If your genotype at rs6133175 is GG, you carry two copies of the effect allele. This genotype is associated with higher plasma Vitamin C levels. That suggests your bloodstream may maintain elevated circulating concentrations of Vitamin C compared to other genotypes.

What this means for you

  • Your SVCT2 transporter may influence how Vitamin C is distributed or retained in circulation.
  • You may have higher measured plasma Vitamin C, but that does not necessarily mean every tissue has more available Vitamin C.
  • Lifestyle factors and diet still strongly influence status; genetics are only one piece of the picture.

Actions to consider

  • Maintain a daily intake of Vitamin C-rich foods: citrus, berries, bell peppers, broccoli, spinach, and kiwi.
  • A typical multivitamin or low dose supplement (for example 100 to 250 mg Vitamin C daily) can be used if dietary intake is low, but discuss with your clinician before starting supplements.
  • Avoid smoking and limit excessive alcohol. Both deplete Vitamin C levels and increase requirements.
  • Check routine labs if you have symptoms or risk factors for deficiency; a plasma ascorbic acid test can confirm status.
1 effect allele (AG) — Likely higher plasma Vitamin C

If your genotype is AG, you carry one copy of the effect allele. This genotype is associated with likely higher plasma Vitamin C levels compared to individuals without the effect allele.

What this means for you

  • Your SVCT2 transport function may slightly favor higher circulating Vitamin C, but individual results can vary.
  • Diet, smoking, medications, and health conditions remain major determinants of Vitamin C status.

Actions to consider

  • Eat Vitamin C-rich foods every day. Focus on whole fruits and vegetables rather than relying solely on supplements.
  • Consider a low dose supplement if your diet is inconsistent or if you have increased need, such as during recovery from illness, heavy training, or significant stress.
  • Discuss with your healthcare provider whether testing is appropriate if you have symptoms like easy bruising, slow wound healing, or unusual fatigue.
0 effect alleles (AA) — Typical Vitamin C transport and plasma levels

If your genotype is AA, you carry two copies of the non-effect allele. This genotype is associated with standard SVCT2 function and typical plasma Vitamin C levels.

What this means for you

  • Your SVCT2 transporter likely supports typical Vitamin C distribution into tissues and normal retention in plasma.
  • You are not genetically predisposed to elevated or reduced circulating Vitamin C based on this variant alone.

Actions to consider

  • Focus on a balanced diet with plentiful Vitamin C sources to preserve normal status.
  • Supplement if dietary intake is inadequate or if you have higher needs due to smoking, certain medications, or medical conditions.
  • Seek testing and medical advice if you have signs of deficiency or increased requirements.

Dietary Tips to Maximize Vitamin C

  • Eat a variety of raw or lightly cooked vegetables and fruits daily to preserve Vitamin C content.
  • Choose whole foods: one medium orange, half a red bell pepper, or a cup of strawberries each provide significant Vitamin C.
  • Freeze or refrigerate produce to slow nutrient loss and avoid prolonged storage at room temperature.
  • When cooking, use quick methods like steaming or stir-frying and avoid long boiling that leaches Vitamin C into water.

Supplement Considerations

  • If you struggle to meet daily needs through food, consider a Vitamin C supplement. Typical supplemental doses range from 100 mg to 500 mg daily for general maintenance.
  • Higher supplemental doses may be used short term under healthcare guidance. Very high doses can cause gastrointestinal discomfort and contribute to kidney stone risk in susceptible individuals.
  • Discuss supplements with your healthcare provider if you are pregnant, breastfeeding, have kidney disease, or take medications that may interact.

Lifestyle and Testing

  • Quit smoking and minimize alcohol to reduce Vitamin C depletion.
  • Manage chronic health conditions and reduce chronic inflammation through healthy diet, sleep, and stress management because inflammation increases antioxidant needs.
  • If you want confirmation of status, ask your healthcare provider about a plasma ascorbic acid test or related nutrient panels.

PlexusDx provides genetic education and interpretations to help you understand predispositions. This information is educational and not medical advice. Always consult your healthcare provider before making changes to your diet, supplements, or treatment based on genetic results.