Oxalate reference · Potatoes and starchy vegetables
Oxalate in corn and polenta
2 mg in a 1/2 cup serving, which the Oxalosis and Hyperoxaluria Foundation bands as low. That is 2 mg per 100 g, for the most representative of the 6 forms measured. It sits above 4 of the 83 foods with a page here.
What is worth knowing about corn and polenta
Sweet corn is low, and so is everything made from it: polenta, grits, cornmeal, tortillas and popcorn all sit in the low band at the portions people eat.
The forms are not interchangeable here. Corn, Grits carries 19 mg a serving, so which one is in the cupboard decides the answer more than the food does.
Every preparation measured
| As listed | Band | mg per 100 g | Serving | mg per serving |
|---|---|---|---|---|
| Corn, boiled or canned | low | 2 | 1/2 cup | 2 |
| Corn, Sweet, fresh or canned | low | 3 | 1/2 cup | 2 |
| Corn, Popcorn, popped | low | 33 | 1 cup | 4 |
| Corn, Tortilla, yellow or white | low | 26 | 1 item | 7 |
| Corn, Cornmeal | low | 37 | 1/4 cup | 11 |
| Corn, Grits | low | 26 | 1/2 cup | 19 |
Bands are per serving as the OHF lists them, so a food can be high per 100 g and low in the portion anybody eats. Turmeric and dried parsley are the clearest cases of that, and neither is a problem in a kitchen.
Nothing in this category measures lower
Corn and polenta is the lowest of the 3 potatoes and starchy vegetables with a page here, ranked by the most representative form of each. If something in this category has come off your plate, this is what it can be replaced with.
| Food | Band | mg per serving | Serving |
|---|---|---|---|
| Corn and polenta (this page) | low | 2 | 1/2 cup |
| Potatoes | low | 18 | 1/2 cup |
| Sweet potato | high | 158 | 1/2 cup |
Before you act on the number
A figure in a table is not a figure in your urine. Oxalate in a plant moves with variety, ripeness, soil, season and cooking — boiling leaches a good deal of it into water that is then poured away. What you absorb also depends on what was on the plate with it, because calcium eaten in the same meal binds oxalate in the gut so that it leaves in the stool instead of the urine.
There is no daily target on this site. The OHF publishes bands per serving, not an allowance, and what any one person should aim for depends on their stone chemistry and their own testing. If you have been given a number, that number wins over anything here.
Restriction is not the first move. Guideline advice for recurrent calcium oxalate stones starts with fluid, with normal calcium taken alongside meals, and with less sodium — and it recommends the fruit and vegetables a low-oxalate list tends to strip out.
All 83 foods, and the full published table · Why a low-oxalate list is the wrong tool for planning a diet · Why calcium belongs with the meal, not off the plate
