Oxalate
What it is and what it does
- Oxalate is a molecule that comes from plants and is also a toxic end-product of metabolism; it has no known physiological function in humans. (Bargagli M, Tio MC, Waikar SS, Ferraro PM (2020). Dietary Oxalate Intake and Kidney Outcomes. Nutrients 12(9):2673 (peer-reviewed review; PMC7551439; CC BY) (DOI 10.3390/nu12092673))
- In foods, oxalate occurs in soluble and insoluble forms; IFCT 2017 measured soluble, insoluble and total oxalates separately. (ICMR-NIN. Indian Food Composition Tables 2017 (Longvah T et al.))
- Indian food composition tables considered oxalic acid an anti-nutrient (from the 1963 edition). (ICMR-NIN. Indian Food Composition Tables 2017 (Longvah T et al.))
- Oxalic acid binds calcium, iron and magnesium, making these minerals unavailable. (Noonan SC, Savage GP (1999). Oxalate content of foods and its effect on humans. Asia Pacific Journal of Clinical Nutrition 8(1):64-74 (peer-reviewed review))
- In the gut, calcium combines with oxalate to form calcium oxalate, and that calcium cannot be absorbed. (Noonan SC, Savage GP (1999). Oxalate content of foods and its effect on humans. Asia Pacific Journal of Clinical Nutrition 8(1):64-74 (peer-reviewed review))
- How much dietary oxalate the gut absorbs depends strongly on how much calcium the diet contains. (Bargagli M, Tio MC, Waikar SS, Ferraro PM (2020). Dietary Oxalate Intake and Kidney Outcomes. Nutrients 12(9):2673 (peer-reviewed review; PMC7551439; CC BY) (DOI 10.3390/nu12092673))
Why it matters
- Calcium absorption from spinach (which contains oxalic acid) is only about 5%, compared with 27% from milk. (NIH Office of Dietary Supplements. Calcium Fact Sheet for Health Professionals (updated 2026-06-22))
- Oxalate matters in finger millet because it interferes with the availability of the grain's calcium. (Abioye VF, Babarinde GO, Ogunlakin GO, Adejuyitan JA, Olatunde SJ, Abioye AO (2022). Varietal and processing influence on nutritional and phytochemical properties of finger millet: A review. Heliyon 8(12):e12310 (peer-reviewed review; PMC9800331; open access) (DOI 10.1016/j.heliyon.2022.e12310))
- Free oxalate and calcium can settle out of the urine and may form kidney stones. (Noonan SC, Savage GP (1999). Oxalate content of foods and its effect on humans. Asia Pacific Journal of Clinical Nutrition 8(1):64-74 (peer-reviewed review))
- In people who eat a wide variety of foods, these effects of oxalic and phytic acid probably have little or no nutritional consequence. (NIH Office of Dietary Supplements. Calcium Fact Sheet for Health Professionals (updated 2026-06-22))
General information, not medical advice — for your own needs, ask a doctor or dietitian.
How much is needed
| Who | Amount | What the figure is | Whose figure |
|---|---|---|---|
| India, all groups | no value set | No ICMR-NIN 2020 value | ICMR-NIN 2020 |
Sources: ICMR-NIN Expert Group. Short Report of Nutrient Requirements for Indians: Recommended Dietary Allowances and Estimated Average Requirements - 2020
In every millet and pseudo-cereal, per 100 g raw
| Grain | Amount | Source |
|---|---|---|
| Oxalate (total) | ||
| Rajgira (amaranth) | 209 mg | IFCT A002 |
| Quinoa | 82.94 mg | IFCT A009 |
| Bajra (pearl millet) | 53.13 mg | IFCT A003 |
| Ragi (finger millet) | 39.58 mg | IFCT A010 |
| Jowar (sorghum) | 28.38 mg | IFCT A005 |
| Little millet | 6.74 mg | IFCT A016 |
| Kodo millet | 3.48 mg | IFCT A017 |
| Oxalate (soluble) | ||
| Bajra (pearl millet) | 43.49 mg | IFCT A003 |
| Quinoa | 42.22 mg | IFCT A009 |
| Rajgira (amaranth) | 32.3 mg | IFCT A002 |
| Ragi (finger millet) | 31.16 mg | IFCT A010 |
| Jowar (sorghum) | 24.62 mg | IFCT A005 |
| Little millet | 5.4 mg | IFCT A016 |
| Kodo millet | 2.57 mg | IFCT A017 |
| Oxalate (insoluble) | ||
| Rajgira (amaranth) | 177 mg | IFCT A002 |
| Quinoa | 40.72 mg | IFCT A009 |
| Bajra (pearl millet) | 9.88 mg | IFCT A003 |
| Ragi (finger millet) | 8.58 mg | IFCT A010 |
| Jowar (sorghum) | 1.72 mg | IFCT A005 |
| Little millet | 1.61 mg | IFCT A016 |
| Kodo millet | 0.65 mg | IFCT A017 |
Each grain has ONE source, named on its page: IFCT = Indian Food Composition Tables 2017 (ICMR-NIN) with its food code; USDA FDC; FAO WAFCT 2019; NIN 2007 via ICAR-IIMR. Values exactly as printed, not converted — tables differ in method, so compare within a source. Published values for the grain, not a laboratory test of our packs.
Absorption and food
- Cooking lowers the oxalate content of foods that contain a lot of it. (Noonan SC, Savage GP (1999). Oxalate content of foods and its effect on humans. Asia Pacific Journal of Clinical Nutrition 8(1):64-74 (peer-reviewed review))
- In one study, boiling taro (colocasia) leaves in water for 40 minutes cut their oxalate by 47%. (Samtiya M, Aluko RE, Dhewa T (2020). Plant food anti-nutritional factors and their reduction strategies: an overview. Food Production, Processing and Nutrition 2:6 (peer-reviewed review; open access, CC BY 4.0) (DOI 10.1186/s43014-020-0020-5))
- Soaking raw foods also lowers oxalate, but useful nutrients such as vitamin C may be lost into the water. (Noonan SC, Savage GP (1999). Oxalate content of foods and its effect on humans. Asia Pacific Journal of Clinical Nutrition 8(1):64-74 (peer-reviewed review))
- In finger millet, oxalic acid falls during germination because soluble oxalate leaches out during steeping. (Abioye VF, Babarinde GO, Ogunlakin GO, Adejuyitan JA, Olatunde SJ, Abioye AO (2022). Varietal and processing influence on nutritional and phytochemical properties of finger millet: A review. Heliyon 8(12):e12310 (peer-reviewed review; PMC9800331; open access) (DOI 10.1016/j.heliyon.2022.e12310))
- In one study of pearl millet, semi-refined flour contained less phytate and oxalate than whole flour. (Samtiya M, Aluko RE, Dhewa T (2020). Plant food anti-nutritional factors and their reduction strategies: an overview. Food Production, Processing and Nutrition 2:6 (peer-reviewed review; open access, CC BY 4.0) (DOI 10.1186/s43014-020-0020-5))
- Oxalate is found in green leafy vegetables, tea, nuts, chocolate and rhubarb. (Bargagli M, Tio MC, Waikar SS, Ferraro PM (2020). Dietary Oxalate Intake and Kidney Outcomes. Nutrients 12(9):2673 (peer-reviewed review; PMC7551439; CC BY) (DOI 10.3390/nu12092673))
- Spinach, collard greens, sweet potatoes, rhubarb and beans are among the foods that contain larger amounts of oxalic acid. (NIH Office of Dietary Supplements. Calcium Fact Sheet for Health Professionals (updated 2026-06-22))
- Plant families with the most oxalate include the arum family (such as colocasia/taro) and the goosefoot family (such as beetroot and spinach). (Noonan SC, Savage GP (1999). Oxalate content of foods and its effect on humans. Asia Pacific Journal of Clinical Nutrition 8(1):64-74 (peer-reviewed review))