Is Butter (Unsalted) Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 1 tbsp (14 g)
Verdict: 🟢 Safe
Per 100g: 0 mg
Data: Harvard T.H. Chan SPH (2024)
Here's the takeaway: Butter (Unsalted) earns a Safe rating (🟢) at 0 mg oxalate per serving. Being under 25 mg means it fits comfortably in everyday eating. Keep your usual habits — adequate fluids and calcium in meals — and Butter (Unsalted) poses no special concern.
Putting Butter (Unsalted) in context: it lands well below the category average of 3 mg. In the database, 95% of dairy & eggs (87 of 91) fall in the 🟢 Safe group (under 25 mg oxalate/serving). The typical dairy & eggs here averages 3 mg oxalate per serving, so Butter (Unsalted) runs 100% 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 dairy & eggs 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 context, Butter (Unsalted) measures 0 mg per 1 tbsp, rated 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 Butter (Unsalted), the measured oxalate value is 0 mg per 1 tbsp (Safe).
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. For context, Butter (Unsalted) measures 0 mg per 1 tbsp, rated Safe.
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. For context, Butter (Unsalted) measures 0 mg per 1 tbsp, rated Safe.