Is Grape-Nuts Flakes Cereal Safe for Kidney Stones? (Caution)
mg oxalate
per serving
Serving: 1 cup (43 g)
Verdict: 🟡 Caution
Per 100g: 57 mg
Data: Harvard T.H. Chan SPH (2024)
Here's the takeaway: Grape-Nuts Flakes Cereal falls in the Caution band (🟡) at 25 mg oxalate per serving. Not off-limits, but not free — moderate portions, a few times a week at most, and preferably with dairy or another calcium source at the same meal.
Putting Grape-Nuts Flakes Cereal in context: it lands well above the category average of 14 mg. In the database, 84% of grains & pasta (170 of 201) fall in the 🟢 Safe group (under 25 mg oxalate/serving). The typical grains & pasta here averages 14 mg oxalate per serving, so Grape-Nuts Flakes Cereal runs 80% above that baseline. That places it on the higher end for oxalate 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 grains & pasta rated Caution 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. Grape-Nuts Flakes Cereal comes in at 25 mg oxalate per 1 cup (Caution) 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 Grape-Nuts Flakes Cereal: 25 mg oxalate per 1 cup — Caution per Harvard (2024).
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 Grape-Nuts Flakes Cereal: 25 mg oxalate per 1 cup — Caution per Harvard (2024).
Should I also check sodium and calcium?
Definitely. Oxalate is only part of the story — high sodium raises calcium in urine, and dietary calcium (from food, not pills) binds oxalate in the gut. The food's main page lists both, so it's worth checking before you plan around it. Grape-Nuts Flakes Cereal comes in at 25 mg oxalate per 1 cup (Caution) in the measured database.