Which Nuts Are Low in Oxalates?

Pistachios, chestnuts, and walnuts consistently rank among the lowest-oxalate nuts, while almonds, Brazil nuts, and pine nuts sit at the opposite extreme. The differences are large enough to matter if you’re prone to kidney stones or following a low-oxalate diet, with the lowest options containing roughly one-sixth the soluble oxalate of the highest. But the picture is more nuanced than a simple ranked list, because the form of oxalate in a nut, the calcium you eat alongside it, and even your gut bacteria all influence how much oxalate your body actually absorbs.

The Lowest-Oxalate Nuts

The most detailed laboratory analysis of nut oxalate levels measured both gastric soluble and intestinal soluble oxalate across a wide range of tree nuts and legume-derived “nuts.” Roasted pistachios and chestnuts came in at the bottom of the scale, with less than 85 mg of gastric soluble oxalate per 100 grams of fresh weight. Their intestinal soluble oxalate levels were similarly low, at 77 and 72 mg per 100 g respectively.¹ A separate study measuring total oxalate in foods available in Southern China confirmed these findings, placing pistachios and walnuts in a low range of roughly 54 to 83 mg total oxalate per 100 g, alongside peanuts.²

Pecans and peanuts (technically a legume, but eaten as a nut) also fall into a relatively low category. Both had gastric soluble oxalate in the range of about 147 to 250 mg per 100 g, and intestinal soluble oxalate between roughly 129 and 173 mg per 100 g.¹ Peanut butter showed similar values to whole peanuts. These are not as low as pistachios or chestnuts, but they’re still well below the high-oxalate group and are generally considered acceptable on a moderate low-oxalate diet.

If you’re looking for a quick mental shortlist, the safest bets are pistachios, chestnuts, and walnuts. Pecans and peanuts sit a step above them but remain in the lower tier. Macadamia nuts, while less studied in the oxalate literature, are generally regarded as low-oxalate as well.

The High-Oxalate Nuts to Limit

Almonds are the nut that trips up the most people. They’re widely recommended for their protein and healthy fat content, but they contain some of the highest soluble oxalate levels of any nut, with gastric soluble oxalate around 492 to 557 mg per 100 g. Brazil nuts and pine nuts fall in the same high bracket.¹ Pine nuts are particularly notable because their intestinal soluble oxalate was the highest measured in the entire study, at 581 mg per 100 g, meaning an outsized proportion of their oxalate is in a form the body can actually absorb.

Cashews occupy a middle ground that makes them somewhat confusing. Their gastric soluble oxalate was in the relatively low range, but their intestinal soluble oxalate was grouped with the high-oxalate nuts, between 216 and 305 mg per 100 g.¹ The Southern China study also placed cashews above 150 mg total oxalate per 100 g, alongside almonds, hazelnuts, and pine nuts.² Hazelnuts, though not always flagged in dietary guides, are in the same bracket. If you’re on a strict low-oxalate protocol, cashews and hazelnuts are worth treating cautiously rather than assuming they’re safe.

Why Soluble Oxalate Matters More Than Total Oxalate

Not all oxalate in a food poses the same risk. Oxalate exists in two forms: soluble and insoluble. Insoluble oxalate is already bound to minerals like calcium within the food itself, which means your gut largely can’t absorb it. Soluble oxalate, on the other hand, dissolves in your digestive fluids and can cross into your bloodstream, eventually reaching your kidneys where it can bind with calcium to form stones.

This is why the research on nuts specifically measures gastric soluble oxalate (what dissolves in stomach conditions) and intestinal soluble oxalate (what dissolves further down in the gut, where absorption mainly happens). A nut with high total oxalate but mostly in the insoluble form would be less of a concern than a nut with moderate total oxalate that’s almost entirely soluble. Pine nuts are the clearest example of this distinction: their intestinal soluble oxalate is dramatically high, making them riskier than their total oxalate number alone would suggest.¹

When you encounter oxalate values online, pay attention to whether the number refers to total oxalate or soluble oxalate. Many food databases report only total oxalate, which can be misleading. A food with 200 mg of total oxalate might be relatively harmless if most of it is insoluble, while a food with 150 mg of mostly soluble oxalate could deliver more oxalate to your kidneys.

How Much Dietary Oxalate Actually Reaches Your Kidneys

Even among high-oxalate foods, the proportion your body absorbs is surprisingly small. A study that tracked oxalate absorption from almonds found that subjects absorbed an average of about 6% of the oxalate from an almond meal, compared to under 2% from black beans.³ That 6% sounds small, but when the starting amount of oxalate is very high, even a modest absorption rate can meaningfully increase what your kidneys have to deal with.

In healthy people, roughly half of urinary oxalate comes from the diet, while the other half is produced internally by normal metabolism, including the breakdown of vitamin C.⁴ A separate review estimated that normal metabolic processes account for about 35 to 55% of circulating oxalates and can generate up to 30 mg of serum oxalate daily on their own.⁵ This means that even if you ate a perfectly zero-oxalate diet, your body would still produce a substantial baseline of oxalate. Dietary restriction can reduce urinary oxalate, but it cannot eliminate it.

The practical upshot: for most people, eating a handful of pistachios or walnuts is not going to meaningfully affect their oxalate burden. The concern is really about large, repeated servings of high-oxalate nuts like almonds, or about people who have a medical reason to keep urinary oxalate especially low.

Eating Calcium Alongside High-Oxalate Nuts

One of the most counterintuitive pieces of dietary advice for people worried about oxalate is to eat more calcium, not less. When calcium is present in the gut at the same time as oxalate, the two bind together before absorption, forming insoluble calcium oxalate that passes harmlessly through your digestive tract. Restricting dietary calcium, on the other hand, actually increases oxalate absorption because more soluble oxalate is left free to cross the intestinal wall.⁶

This has direct implications for how you eat nuts. If you’re snacking on almonds or cashews and you’re concerned about oxalate, pairing them with a calcium-rich food like cheese or yogurt can reduce the amount of oxalate your body absorbs. The calcium needs to be in the same meal or snack, not taken hours apart, because the binding happens in the gut during digestion. Calcium supplements taken at mealtime can work too, though getting calcium from food is generally preferred.

This calcium-binding principle also explains an old misunderstanding. People with calcium oxalate kidney stones used to be told to avoid calcium-rich foods, under the logic that less calcium meant fewer stones. Research has flipped that recommendation. Low-calcium diets can actually increase stone risk by freeing up more oxalate for absorption, while adequate calcium intake tends to lower urinary oxalate levels.

The Nut Milk Question

Plant-based milks have become common enough that their oxalate content matters for people managing stone risk. A study comparing several popular alternatives found that almond milk had the highest oxalate concentration, followed by cashew, hazelnut, and soy milk. Oat, macadamia, and rice milk had much lower oxalate levels and parameters more similar to dairy milk. Oat milk came closest to matching dairy overall, with moderate calcium and potassium alongside low oxalate.⁷

This makes sense given what we already know about the nuts themselves. Almond milk is made by grinding almonds and straining the liquid, so it carries along a portion of the soluble oxalate. The same logic applies to cashew milk. If you’ve switched to almond milk as a daily staple, especially in larger quantities like smoothies or coffee throughout the day, you may be getting a steady stream of oxalate you hadn’t accounted for. Oat, rice, or macadamia milk are better alternatives from an oxalate standpoint.

Gut Bacteria That Break Down Oxalate

Your body has a somewhat underappreciated defense against dietary oxalate: a bacterium called Oxalobacter formigenes that lives in the colon and uses oxalate as its sole energy source. It essentially eats oxalate before your body can absorb it. Research has shown that this organism can reduce urinary oxalate levels following an oxalate-rich meal, and its absence from the gut has been linked to higher urinary oxalate and greater kidney stone risk.⁸

The problem is that Oxalobacter is fragile. Antibiotic courses can wipe it out, and once it’s gone, it may not come back on its own. This has led researchers to speculate that antibiotic exposure could be an underrecognized contributor to calcium oxalate stone disease. People who’ve had multiple rounds of broad-spectrum antibiotics may have less colonic oxalate-degrading capacity, making dietary oxalate restriction more important for them than for someone with an intact gut microbiome.

Animal and human volunteer studies have explored giving Oxalobacter as a therapeutic probiotic, and early results showed it could establish in the gut and reduce urinary oxalate after an oxalate load.⁸ This line of research is still developing, but it underscores that the relationship between the oxalate you eat and the oxalate that ends up in your urine is mediated by your individual biology, not just the food label.

Why Oxalate Levels Vary Between Studies

If you’ve compared nut oxalate values from different sources and noticed they don’t always agree, you’re not imagining it. Oxalate content in the same type of nut can vary depending on where it was grown, how it was processed, the variety of the plant, and how the lab measured it. The study from Southern China, for example, placed almonds, cashews, and hazelnuts all above 150 mg total oxalate per 100 g, while the analysis focused on soluble fractions categorized cashews differently depending on whether gastric or intestinal conditions were being tested.²¹

Plants produce oxalate partly as a way to regulate calcium and protect against being eaten by herbivores.⁹ Growing conditions that affect calcium availability or pest pressure can shift oxalate concentrations from one harvest to the next. Soil mineral content, climate, and even the maturity of the nut at harvest all play roles. Roasting may also alter the soluble-to-insoluble ratio, though the data on processing effects in nuts specifically is limited compared to vegetables where boiling and blanching have been well studied.

For practical purposes, the broad categories are stable enough to guide decisions. Pistachios, chestnuts, and walnuts are reliably low. Almonds, Brazil nuts, and pine nuts are reliably high. But the exact milligram figure for any given batch of cashews or pecans can shift, so treating the middle-tier nuts with a margin of caution is reasonable if you’re managing a specific medical threshold.

Serving Size and Context

Most of the oxalate values reported in research are per 100 grams, which is a useful benchmark but doesn’t match how most people actually eat nuts. A typical handful of nuts is roughly 28 to 30 grams, or about one ounce. At that serving size, even almonds deliver roughly a third of their per-100-gram oxalate load. A handful of pistachios delivers far less. Portion control matters more than most dietary guides acknowledge when the goal is managing oxalate intake rather than eliminating it entirely.

It’s also worth keeping nuts in context alongside other high-oxalate foods. Spinach, rhubarb, and beets are often far higher in oxalate than any nut. Spinach can contain over 600 mg of soluble oxalate per 100 g, making it one of the most concentrated dietary sources. Someone who eats a large spinach salad daily is probably getting more oxalate from that salad than from occasional nut snacking. For people trying to lower their total dietary oxalate, identifying the biggest contributors in their specific diet is more productive than blanket-eliminating all nuts.

If you’re working with a urologist or dietitian and have been told to keep daily oxalate intake below a certain threshold, tracking your nut choices is part of the puzzle. But for the general population without a history of calcium oxalate stones, the nutritional benefits of moderate nut consumption, including heart-healthy fats, fiber, and minerals, typically outweigh the oxalate concern. The question “which nuts are low in oxalate” is most relevant for the subset of people who have a medical reason to care, and for those people, reaching for pistachios or walnuts instead of almonds is a straightforward swap that doesn’t require giving up nuts altogether.