Is Grapes (Green or Red) Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 1 cup (92 g)
Verdict: 🟢 Safe
Per 100g: 4 mg
Data: Harvard T.H. Chan SPH (2024)
In practical terms, Grapes (Green or Red) is a low-risk food for kidney stone patients. Its 3 mg oxalate per serving stays under the 25 mg line, so it can appear in your regular rotation without extra calculation. As always, staying hydrated and getting dietary calcium supports stone prevention.
Among fruits, Grapes (Green or Red) 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 Grapes (Green or Red) is 86% below the category norm. Within its specific category, Grapes (Green or Red) 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 context, Grapes (Green or Red) measures 3 mg per 1 cup, rated Safe.
Can I eat this food every day?
For Safe foods (under 25 mg/serving), daily use is generally fine. Caution and Avoid foods work better as occasional items — rotate them with safer options so no single high-oxalate food becomes a habit. Applied to Grapes (Green or Red): 3 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. Grapes (Green or Red) comes in at 3 mg oxalate per 1 cup (Safe) in the measured database.
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 Grapes (Green or Red), the measured oxalate value is 3 mg per 1 cup (Safe).