How Much Oxalate Is in Onion powder?
mg oxalate
per serving
Serving: 1 tsp (2 g)
Verdict: 🟢 Safe
Per 100g: 50 mg
Data: Harvard T.H. Chan SPH (2024)
The bottom line for Onion powder: Safe (🟢), with 1 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 Onion powder 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 Onion powder runs 97% 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?
The per-100g number lets you compare foods on an equal-weight basis, regardless of serving size. It's useful when two foods have very different typical serving sizes, or when you eat more or less than a standard serving. For Onion powder, the measured oxalate value is 1 mg per 1 tsp (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. For context, Onion powder measures 1 mg per 1 tsp, rated 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. For Onion powder, the measured oxalate value is 1 mg per 1 tsp (Safe).