@Serotoninskeptic

The values above need to be revised. The doses of calcium needed in practice to complex with oxalate are higher than expected, and how calcium interacts with phosphate is relevant:

"The degree of interference reported here (~166 mg phosphorus for every 500 mg ingested calcium—0.4 mmol phosphorus for every mmol calcium) is substantially less than might have been predicted from simple stoichiometry. A 1:1 molar ratio for CaHPO4 would predict binding of 388 mg phosphorus by 500 mg calcium and, for Ca3(PO4)2 at a Ca:P molar ratio of 1.5:1.0, 258 mg phosphorus would be bound per 500 mg calcium. A molar ratio of 1:1 seems more likely at digestate pH values below 7.0. Even at the upper end of the confidence interval for the regression model—210 mg (6.8 mmol)—binding would still be substantially less than the lowest stoichiometric prediction. This discrepancy may be partly due to rapid absorption of phosphorus in the duodenum well before calcium and phosphorus complexes can form in the chyme. In any event it undoubtedly reflects the complexity and multiplicity of the interactions within the digestive residue."

(10.1080/07315724.2002.10719216)

Compare them:

Predicted: Ca 1:1 P Practical: Ca 2.5:1 P

For oxalate:

Predicted: Ca 1:1 Oxa Practical: Ca ?:1 Oxa

If we treat the interaction with oxalate as that with phosphorus (2.5:1) and adjust for mass (2.5:2), we would need 125 mg of calcium for every 100 mg of soluble oxalate.

One problem is guessing how much is soluble from the total oxalate content of a food. Based on the last two 'Cooked' columns (⇈), it's all over the place.

Another problem is the additional confounders. Member 'blabla' posted this elsewhere:

cab6428c-10ca-4047-a0e4-08d21350c5b1-image.png
⠀(10.1097/01.asn.0000127864.26968.7f)

Up to 800 mg: dietary calcium alone More than 800 mg: dietary calcium and supplements (400 mg and 1000 mg)

Only the supplements were dosed with the labeled oxalate, suggesting that indirect interference is possible, but notice the degree of variations at low intakes. If you must supplement, it's preferable to dose in the same meal:

edacf8d3-917e-41a6-b44f-6a24525a3abb-image.png
⠀(10.4065/79.1.91)

But when the diet contains enough calcium (1000 mg), adding more seems unnecessary because a further reduction is minimal.