What is rs33972313 (SLC23A1) nd Why Does the Nutrient Zoomer Test for It?

Vitamin C transporter variant

rs33972313 is a single-nucleotide variant in SLC23A1, the gene that encodes the sodium-dependent vitamin C transporter SVCT1. Measuring this variant helps explain individual differences in vitamin C absorption, circulating levels, and kidney handling, adding context to nutrient test results.

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rs33972313 (SLC23A1)

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About rs33972313 (SLC23A1)

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About rs33972313 (SLC23A1)

Overview and History

SLC23A1 belongs to the solute carrier (SLC) family and encodes SVCT1, a membrane transporter that moves ascorbate (vitamin C) into cells and participates in renal reabsorption. SVCT1 is expressed in tissues involved in whole-body vitamin C handling, including the intestine, liver, and kidney. rs33972313 is a single-nucleotide polymorphism identified in population studies of vitamin C biology. Research has associated this variant with altered transporter function and measurable differences in plasma ascorbate and urinary excretion, making it relevant for understanding individual variation in vitamin C status.

Interpreting Highs and Lows

Genetic variants that reduce SVCT1 function are commonly associated with lower circulating vitamin C and relatively greater urinary loss, while genotypes linked to normal or higher transport function tend to align with expected or higher plasma ascorbate. These patterns describe associations, not diagnoses, and actual vitamin C status is also shaped by diet, kidney function, and other genetic or metabolic factors. Interpretation is most informative when combined with blood and urine nutrient measurements and the broader Nutrient Zoomer panel.

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Included in the Nutrient Zoomer to evaluate inherited differences in vitamin C transport capacity, rs33972313 helps explain why measured ascorbate levels may diverge from intake. When combined with direct vitamin C and other nutrient markers, it supports personalized interpretation of nutrient balance and renal handling.

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rs33972313 (SLC23A1) FAQs

What is rs33972313 (SLC23A1) and why is it important?

rs33972313 is a genetic variant in SLC23A1, the gene for the SVCT1 vitamin C transporter. Different versions of this SNP can change how efficiently vitamin C is absorbed and reabsorbed by the kidneys. Knowing your genotype helps explain why two people with similar diets can have different blood vitamin C levels, aiding interpretation of nutrient testing.

What does it mean if my rs33972313 (SLC23A1) levels are low?

If your genotype is the version that reduces SVCT1 function, studies associate it with lower circulating vitamin C and greater urinary loss. That association can help explain low blood ascorbate despite adequate intake, but it is one piece of the picture and should be interpreted alongside measured vitamin C, diet, and other test results.

What does it mean if my rs33972313 (SLC23A1) levels are high?

If your genotype corresponds to normal or higher SVCT1 function, it is generally associated with expected or higher plasma vitamin C and efficient renal reabsorption. This association may help explain adequate blood ascorbate levels, but clinical interpretation depends on measured nutrient values, diet, and other genetic and metabolic markers.

Why is this biomarker included in the Nutrient Zoomer?

rs33972313 provides inherited context for vitamin C transport and renal handling, helping providers link measured ascorbate levels to genetic predisposition. When reviewed with blood, urine, and other nutrient markers, it sharpens pattern recognition and supports more precise interpretation of nutrient status.

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