How Much Oxalate Is in Oyster?
mg oxalate
per serving
Serving: 1 oz (28 g)
Verdict: 🟢 Safe
Per 100g: 22 mg
Data: Harvard T.H. Chan SPH (2024)
The bottom line for Oyster: Safe (🟢), with 6 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 Oyster in context: it lands well above the category average of 2 mg. In the database, 100% of seafood (55 of 55) fall in the 🟢 Safe group (under 25 mg oxalate/serving). The typical seafood here averages 2 mg oxalate per serving, so Oyster runs 288% 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 seafood 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. Applied to Oyster: 6 mg oxalate per 1 oz — Safe per Harvard (2024).
How accurate is the oxalate measurement?
The measurements use ion chromatography, the accepted reference method for oxalate. That means real lab values for each food rather than inferred numbers. Some natural variation exists between samples, but this is the strongest published data set. For Oyster, the measured oxalate value is 6 mg per 1 oz (Safe).
How does this compare to other foods?
The ratings split at 25 mg (Safe) and 100 mg (Avoid), with 25-99 mg in the Caution band. For context against similar foods, the category pages on OxalateWatch rank every item in that group by oxalate. Oyster comes in at 6 mg oxalate per 1 oz (Safe) in the measured database.