Is Granny smith Apple Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 1 medium (182 g)
Verdict: 🟢 Safe
Per 100g: 0.5 mg
Data: Harvard T.H. Chan SPH (2024)
What this means: Granny smith Apple is rated Safe (🟢). At 1 mg oxalate per serving, it's well under the 25 mg safety threshold. You can include it regularly in a kidney stone diet. Pair it with calcium-rich foods (dairy, fortified plant milks) for additional protection, and drink plenty of water throughout the day.
Among fruits, Granny smith Apple sits well below the category average of 21 mg. For context, 101 out of 113 fruits (89%) are rated 🟢 Safe (under 25 mg oxalate/serving). The average fruits in our database has 21 mg oxalate per serving — which means Granny smith Apple is 96% below the category norm. Within its specific category, Granny smith Apple ranks among the lower-oxalate options. This context matters because two 'Safe' foods can have very different oxalate levels — one might have 5 mg while another has 24 mg. Both are Safe, but the first gives you more dietary flexibility. Browse all fruits rated Safe to compare within the same verdict level.
Why does the safe threshold matter?
The 25 mg per serving threshold is based on clinical guidance for kidney stone patients. Harvard's lab data (2024) provides the most reliable oxalate measurements available — no database estimates, direct lab analysis. For Granny smith Apple, the measured oxalate value is 1 mg per 1 medium (Safe).
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. For Granny smith Apple, the measured oxalate value is 1 mg per 1 medium (Safe).
Where does the oxalate data come from?
Every oxalate figure is sourced from Harvard T.H. Chan SPH (2024), distributed via the OHF database. The values come from actual lab measurements of the foods — not from database averages or estimates. Applied to Granny smith Apple: 1 mg oxalate per 1 medium — Safe per Harvard (2024).
Should I also check sodium and calcium?
Yes — kidney stone risk isn't just about oxalate. High sodium increases urinary calcium (a stone promoter). Adequate dietary calcium (from food, not supplements) actually binds oxalate in your gut. Check the food's full nutrition page for the complete picture. For Granny smith Apple, the measured oxalate value is 1 mg per 1 medium (Safe).