Is Romaine Lettuce Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 1 cup shredded (47 g)
Verdict: 🟢 Safe
Per 100g: 2.1 mg
Data: Harvard T.H. Chan SPH (2024)
What this means: Romaine Lettuce 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 vegetables, Romaine Lettuce sits well below the category average of 27 mg. For context, 219 out of 271 vegetables (80%) are rated 🟢 Safe (under 25 mg oxalate/serving). The average vegetables in our database has 27 mg oxalate per serving — which means Romaine Lettuce is 97% below the category norm. Within its specific category, Romaine Lettuce 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 vegetables rated Safe to compare within the same verdict level.
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. For Romaine Lettuce, the measured oxalate value is 1 mg per 1 cup shredded (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 context, Romaine Lettuce measures 1 mg per 1 cup shredded, rated 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 Romaine Lettuce: 1 mg oxalate per 1 cup shredded — Safe 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. For context, Romaine Lettuce measures 1 mg per 1 cup shredded, rated Safe.