Is Kale (Simmered or steamed) Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 1/2 cup cooked (65 g)
Verdict: 🟢 Safe
Per 100g: 5 mg
Data: Harvard T.H. Chan SPH (2024)
The bottom line for Kale (Simmered or steamed): Safe (🟢), with 3 mg oxalate per serving — comfortably below the 25 mg safe cutoff. There's no need to limit it. Just keep your usual kidney stone basics in place: water throughout the day and calcium-rich foods at meals.
Putting Kale (Simmered or steamed) in context: it lands well below the category average of 27 mg. In the database, 80% of vegetables (219 of 271) fall in the 🟢 Safe group (under 25 mg oxalate/serving). The typical vegetables here averages 27 mg oxalate per serving, so Kale (Simmered or steamed) runs 89% below that baseline. That places it among the lower-oxalate options in its category. Why this matters: the gap between two Safe foods can be wide — one may hold 5 mg oxalate while another sits at 24 mg. The lower one leaves more room in your day. See all vegetables rated Safe for a full side-by-side.
Why does the safe threshold matter?
The 25 mg line is the reference point clinicians use to separate everyday foods from ones that need caution. Every value on this page traces back to Harvard's 2024 lab analysis, so the threshold is applied to measured data rather than estimates. Kale (Simmered or steamed) comes in at 3 mg oxalate per 1/2 cup cooked (Safe) in the measured database.
Can I eat this food every day?
Daily eating is fine for Safe foods (under 25 mg/serving). For Caution or Avoid foods, spread them out and alternate with low-oxalate picks. The idea is keeping your weekly oxalate load manageable, not eliminating any single food. Applied to Kale (Simmered or steamed): 3 mg oxalate per 1/2 cup cooked — Safe per Harvard (2024).
Where does the oxalate data come from?
The numbers come from Harvard T.H. Chan SPH's 2024 laboratory measurements, published through the OHF database. Direct lab analysis, which is why they're treated as the reference values for food oxalate. Applied to Kale (Simmered or steamed): 3 mg oxalate per 1/2 cup cooked — Safe per Harvard (2024).
Should I also check sodium and calcium?
Yes — oxalate alone doesn't decide stone risk. Sodium pushes more calcium into urine, and calcium from food (not supplements) helps bind oxalate during digestion. The main food page covers sodium and calcium alongside oxalate. Kale (Simmered or steamed) comes in at 3 mg oxalate per 1/2 cup cooked (Safe) in the measured database.