How Much Oxalate Is in portobello?
mg oxalate
per serving
Serving: 1 cup sliced (121 g)
Verdict: 🟢 Safe
Per 100g: 1.7 mg
Data: Harvard T.H. Chan SPH (2024)
The bottom line for portobello: Safe (🟢), with 2 mg oxalate per serving — comfortably below the 25 mg safe cutoff. There's no need to limit it. Just keep your usual kidney stone basics in place: water throughout the day and calcium-rich foods at meals.
Putting portobello in context: it lands well below the category average of 27 mg. In the database, 80% of vegetables (219 of 271) fall in the 🟢 Safe group (under 25 mg oxalate/serving). The typical vegetables here averages 27 mg oxalate per serving, so portobello runs 93% 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 vegetables rated Safe for a full side-by-side.
Why does oxalate per 100g matter?
Per-100g values put every food on the same scale, which is handy when serving sizes differ a lot between foods — or when your portion doesn't match the standard serving. It lets you compare apples to apples on oxalate density. For portobello, the measured oxalate value is 2 mg per 1 cup sliced (Safe).
How accurate is the oxalate measurement?
Harvard's 2024 analysis used ion chromatography — the gold standard for oxalate measurement. These are direct lab values, not estimates or database calculations. Variability exists between samples, but this is the most reliable reference available. Applied to portobello: 2 mg oxalate per 1 cup sliced — Safe per Harvard (2024).
How does this compare to other foods?
Foods under 25 mg per serving are rated Safe. Foods between 25-99 mg are Caution. 100+ mg is Avoid. Check the food's category page on OxalateWatch to see how it compares to similar foods. For portobello, the measured oxalate value is 2 mg per 1 cup sliced (Safe).