Is sour Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 1 cup (155 g)
Verdict: 🟢 Safe
Per 100g: 0.6 mg
Data: Harvard T.H. Chan SPH (2024)
The bottom line for sour: Safe (🟢), with 1 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 sour in context: it lands well below the category average of 21 mg. In the database, 89% of fruits (101 of 113) fall in the 🟢 Safe group (under 25 mg oxalate/serving). The typical fruits here averages 21 mg oxalate per serving, so sour runs 96% 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 fruits rated Safe for a full side-by-side.
Why does the safe threshold matter?
The 25 mg cutoff comes from clinical guidance for stone formers. Below it, a food's oxalate contribution is small enough not to move the needle for most patients. Harvard's 2024 lab data sits behind these figures — direct measurements, not estimates. For sour, the measured oxalate value is 1 mg per 1 cup (Safe).
Can I eat this food every day?
If it's in the Safe zone (under 25 mg/serving), yes — it can be a regular part of your diet. For Caution or Avoid foods, frequency matters. Rotate them with lower-oxalate options throughout the week. Applied to sour: 1 mg oxalate per 1 cup — Safe per Harvard (2024).
Where does the oxalate data come from?
Harvard T.H. Chan School of Public Health (2024) via the OHF database. These are direct laboratory measurements — the most reliable oxalate data available for food. For sour, the measured oxalate value is 1 mg per 1 cup (Safe).
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. For context, sour measures 1 mg per 1 cup, rated Safe.