Cashews are a high-oxalate food. A one-ounce serving (about 18 kernels) contains roughly 49 mg of oxalate, which is enough to nearly hit the entire daily limit on a low-oxalate diet in a single handful. If you’re watching your oxalate intake because of kidney stones or other concerns, cashews deserve attention.
How Cashews Compare to Other Nuts
Among tree nuts, cashews fall in the middle of the oxalate spectrum. Almonds are the biggest offenders at about 122 mg per ounce, more than double the amount in cashews. Walnuts come in at around 31 mg per cup (roughly 7 nuts), and pecans sit lower at about 10 mg per ounce. Macadamia nuts are among the lowest at approximately 42 mg per 100 grams of fresh weight, which works out to only about 12 mg in a typical one-ounce serving.
What makes cashews particularly noteworthy isn’t just the total oxalate content but how much of it your body can actually absorb. Research measuring how oxalate behaves during digestion found that about 85% of the oxalate in roasted cashews remains soluble in the intestines, meaning it’s available for absorption. Compare that to almonds, where only about 41% of the oxalate stays soluble because the rest binds into insoluble forms your body can’t take up. So while almonds contain more total oxalate, cashews deliver a higher proportion of what they have into your system.
What This Means on a Low-Oxalate Diet
Most medical guidelines recommend keeping oxalate intake between 40 and 50 mg per day if you’re on a low-oxalate diet, typically prescribed for people with a history of calcium oxalate kidney stones. A single ounce of cashews puts you right at that ceiling, leaving almost no room for oxalate from other foods you eat that day. Spinach, sweet potatoes, chocolate, tea, and many other common foods also contribute oxalate, so the math gets tight quickly.
That said, the American Urological Association’s guidelines on kidney stone prevention specifically caution against overly restrictive diets. Many high-oxalate foods carry real nutritional benefits, and blanket elimination isn’t the goal. The recommendation is to limit oxalate-rich foods while maintaining normal calcium intake, not to avoid every food that contains oxalate.
Pairing Cashews With Calcium
One of the most practical ways to reduce how much oxalate your body absorbs is to eat calcium-rich foods at the same meal. Oxalate binds readily to calcium in your digestive tract, forming a compound that passes through without being absorbed. This means eating cashews alongside yogurt, cheese, or milk can meaningfully reduce the amount of oxalate that reaches your kidneys.
Clinical guidelines for stone prevention reflect this: patients are advised to consume calcium from foods and beverages primarily at meals to enhance this binding effect, with a target of 1,000 to 1,200 mg of calcium daily. The key is getting calcium from food rather than supplements, and timing it with oxalate-containing meals rather than taking it separately.
Roasting and Soaking Don’t Help Much
If you were hoping that roasting or soaking cashews would lower their oxalate content, the evidence is disappointing. While soaking and boiling can reduce oxalate in some foods (particularly leafy greens, where oxalate leaches into cooking water), research has found that roasting does not significantly affect the oxalate content of cashews, peanuts, or almonds. Since most cashews are sold roasted, this means the processing they’ve already undergone hasn’t meaningfully changed their oxalate load.
Lower-Oxalate Alternatives
If you need to keep oxalate low but still want nuts and seeds in your diet, several options work well:
- Flaxseed: 0 mg per tablespoon
- Sunflower seeds: 12 mg per cup
- Peanut butter: 13 mg per tablespoon
- Pistachios: 14 mg per ounce (about 48 nuts)
- Pecans: 10 mg per ounce
These options let you get the healthy fats, protein, and minerals that nuts provide without consuming a large share of your daily oxalate budget in one snack. Pistachios and pecans are the closest substitutes if you’re looking for something with a similar texture and snacking appeal to cashews.