Most stone talk is about the oxalate you eat. But a meaningful share of the oxalate in urine is made inside the body, and one vitamin sits at the control point: B6. Understanding that switch explains why a deficiency can quietly raise oxalate even on a clean diet.
In the liver, an enzyme called AGT (alanine:glyoxylate aminotransferase) uses vitamin B6 — in its active form, pyridoxal phosphate — to convert glyoxylate into glycine, a harmless amino acid. When B6 is lacking, that conversion stalls. Glyoxylate piles up and gets shunted down another path that ends in oxalate. A 2026 rat study made the point sharply: B6-deficient animals developed a "functional" mimic of a genetic stone disorder, because the enzyme was present but had lost its required cofactor.
This is the same mechanism behind type 1 primary hyperoxaluria, a rare genetic disease where the AGT enzyme itself is broken. There, pharmacologic B6 helps a subset of patients (roughly a third, in registry data) lower urine oxalate by 30 percent or more. That is a special, physician-managed situation — not the everyday stone former.
The foods that carry B6 tend to be clean on oxalate, which makes them easy additions:
| Food | Oxalate (mg) | Serving | Rating |
|---|---|---|---|
| Chicken breast, roasted | 0 mg | 4 oz | Safe |
| Salmon, cooked | 0 mg | 4 oz | Safe |
| Tuna, canned in water | 0 mg | 3 oz | Safe |
| Banana | 6 mg | 1 medium | Safe |
| Oatmeal, cooked | 2 mg | 1 cup | Safe |
Poultry, fish, banana, and oats are B6 sources that sit at zero or near-zero oxalate. For someone whose urine oxalate is high and whose diet is already low in oxalate, a B6 check (via a clinician) is one of the variables worth ruling out — because the problem may be endogenous, not dietary.
For most people, the lesson is indirect: keep B6 adequate through ordinary food rather than chasing supplements. The 2026 rat work matters most as a reminder that "high urine oxalate despite a low-oxalate diet" is a real pattern with a metabolic cause, and that a 24-hour urine test plus a nutrient workup is the right next step — not another round of cutting spinach. High-dose B6 has its own risk (nerve toxicity at sustained high doses), so dose decisions belong with a doctor.
See how oxalate values are measured and verified on our data methodology page.