Is Blueberries (Fresh or frozen 2) Safe for Kidney Stones?
mg oxalate
per serving
Serving: 1 cup (200 g)
Verdict: 🟡 Caution
Per 100g: 14 mg
Data: Harvard T.H. Chan SPH (2024)
In practical terms, Blueberries (Fresh or frozen 2) sits in the 25-99 mg range with 27 mg per serving, so treat it as a sometimes-food. Keep servings modest, don't stack it with other moderate-oxalate items in one day, and pair it with calcium to blunt absorption.
Among fruits, Blueberries (Fresh or frozen 2) sits close to 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 Blueberries (Fresh or frozen 2) is 27% above the category norm. Within its specific category, Blueberries (Fresh or frozen 2) ranks near the middle of the pack. 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 Caution 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 Blueberries (Fresh or frozen 2), the measured oxalate value is 27 mg per 1 cup (Caution).
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 Blueberries (Fresh or frozen 2): 27 mg oxalate per 1 cup — Caution 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. Blueberries (Fresh or frozen 2) comes in at 27 mg oxalate per 1 cup (Caution) 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. Blueberries (Fresh or frozen 2) comes in at 27 mg oxalate per 1 cup (Caution) in the measured database.