Stone-forming patients can safely eat tofu.
Both gypsum-set (calcium sulfate) and brine-set (magnesium chloride) tofu contain very little oxalate, and further-processed products such as dried tofu are also low in oxalate.
During production, soybeans are soaked for hours, so most of the soluble purines leach out; the curd is then diluted with large amounts of water, further lowering purine concentration.
Moreover, the calcium supplied by tofu is beneficial: dietary calcium binds oxalate in the gut, reducing its absorption and lowering urinary oxalate—an important protective factor against calcium-oxalate stones.
Therefore, patients with kidney stones do not need to avoid tofu.
The key precautions are:
- Drink plenty of fluids
- Consume moderate amounts of high-quality protein (eggs, lean meat, milk)
- Keep salt intake low
- Limit truly high-oxalate foods such as spinach, asparagus, peanuts, and soy flour
Healthy individuals have no reason to fear that tofu or other soy products will provoke stones, and patients with gallstones or other stone types generally do not need to restrict tofu either.
| Key Point | Plain-English Summary |
|---|---|
| Oxalate content of tofu | Very low; gypsum- or brine-set tofu and dried tofu are safe. |
| Purine content | Most purines are lost during soaking and dilution; final level in tofu is negligible. |
| Calcium effect | Calcium in tofu binds dietary oxalate in the gut, lowering urinary oxalate and stone risk. |
| Kidney-stone patients | Can eat tofu; focus on high fluid intake, moderate animal protein, low salt, and avoid high-oxalate foods (spinach, asparagus, peanuts, soy flour). |
| Healthy adults & other stone types | No need to restrict tofu or soy products. |