🟢 Safe
Oxalate <25 mg/serving
🟡 Caution
Oxalate 25-99 mg/serving
🔴 Avoid
Oxalate ≥100 mg/serving
🟢

Fiddleheads (Ostrich ferns), boiled 15 min

🟢 Safe — Low Oxalate
19 mg oxalate / serving
Serving: 1/2 cup (64 g) | Per 100 g: 30 mg
✓ Medically Reviewed Content reviewed by OxalateWatch Editorial Team. Based on Harvard T.H. Chan SPH oxalate data (2024) and NKF/AUA dietary guidelines.

📊 Nutrition at a Glance

19 mg
Oxalate / serving
Low Oxalate
75 mg
Sodium / 100g
Low Na
21.8 g
Protein / 100g
Tier 1
6 mg
Calcium / 100g
Tier 1

📏 Oxalate by Serving Size

ServingWeightOxalateVerdict
1/2 cup64 g19 mg Safe
2 x 1/2 cup128 g38 mg Caution
½ x 1/2 cup32 g9.5 mg Safe

🏷️ Tags

Condiments 🟢 Oxalate Safe Low Oxalate Plant-Based

🟢 See all Condiments rated Safe for kidney stones →

🔗 Related Foods

❓ Frequently Asked Questions

Should I avoid Fiddleheads (Ostrich ferns) if I have kidney stones?

It's fine. Fiddleheads (Ostrich ferns) has 19 mg of oxalate per 1/2 cup. That's low enough that kidney stone patients don't really need to worry about it. Harvard did the measuring, not us.

How much oxalate is in Fiddleheads (Ostrich ferns)?

The exact figure: 19 mg of oxalate per 1/2 cup of Fiddleheads (Ostrich ferns). Works out to 30 mg/100g. This is the number kidney stone patients actually need. Harvard (2024) verified.

Is Fiddleheads (Ostrich ferns) a high-oxalate food?

It's low. 19 mg per 1/2 cup is well under the 25 mg danger line. Fiddleheads (Ostrich ferns) is not the food you need to worry about.

What can I eat instead of Fiddleheads (Ostrich ferns)?

There are almost always safer swaps in the same food family. For Fiddleheads (Ostrich ferns), check the related foods section below — the green-marked ones are your best bets. All verified by Harvard (2024).

How much sodium does Fiddleheads (Ostrich ferns) have?

Sodium's not the issue here. Fiddleheads (Ostrich ferns) has 75 mg per 100g — comfortably low. No need to worry about salt pushing extra calcium into your urine with this food.

🔍 Explore More About This Food

📚 Data Sources

Oxalate: Harvard T.H. Chan School of Public Health (2024) via OHF. Nutrition: USDA FoodData Central (SR Legacy 2018 & Foundation Foods).

📖 Key Scientific References

Taylor EN, Curhan GC. Oxalate intake and the risk for nephrolithiasis. J Am Soc Nephrol. 2007;18(7):2198-2204. PMID: 17538185
Borghi L, Schianchi T, Meschi T, et al. Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. N Engl J Med. 2002;346(2):77-84. DOI: 10.1056/NEJMoa010369
Fink HA, Akornor JW, Garimella PS, et al. Diet, fluid, or supplements for secondary prevention of nephrolithiasis. Eur Urol. 2009;56(1):72-80. DOI: 10.1016/j.eururo.2009.03.031
Ferraro PM, Taylor EN, Gambaro G, Curhan GC. Dietary and lifestyle factors for primary prevention of nephrolithiasis. BMC Nephrol. 2020;21(1):267. PMID: 32652950
Pearle MS, Goldfarb DS, Assimos DG, et al. Medical management of kidney stones: AUA guideline. J Urol. 2014;192(2):316-324. DOI: 10.1016/j.juro.2014.05.006
Liebman M, Costa G. Effects of calcium and magnesium on urinary oxalate excretion after oxalate loads. J Urol. 2000;163(5):1565-1569. PMID: 10751889
Holmes RP, Assimos DG. The impact of dietary oxalate on kidney stone formation. Urol Res. 2004;32(5):311-316. DOI: 10.1007/s00240-004-0437-3
Lin BB, Lin ME, Huang RH, et al. Dietary treatment and fluid intake for prevention of recurrent calcium stones. PLoS One. 2021;16(4):e0250257. PMID: 33872340
This is dietary reference information, NOT medical advice. Talk to your doctor or a registered dietitian before changing your diet. Oxalate tolerance varies by person, stone type, and medication.