Can we eat cashew nuts in a kidney stone? A closer look at oxalates and nut consumption

October 23, 2025 •

3 min read

According to the National Kidney Foundation, the most common type of kidney stone is the calcium oxalate stone, accounting for approximately 80% of all cases. For this reason, anyone prone to stones often asks: can we eat cashew nuts in a kidney stone? The answer is not a simple yes or no, as cashews contain moderate to high levels of oxalates, a key component in forming this type of stone.

Quick Summary

Cashew nuts contain significant levels of oxalates, which can increase the risk of forming calcium oxalate kidney stones, particularly in susceptible individuals. Dietary management involves moderating portion sizes and consuming calcium-rich foods alongside high-oxalate items to reduce absorption.

Key Points

High Oxalate Content: Cashew nuts contain moderate to high levels of oxalates, which can increase the risk of forming calcium oxalate kidney stones.
Not a Complete Ban: For many people, moderate consumption of cashews may not cause issues, but those prone to stones should be mindful of portion sizes.
Calcium is Key: Eating high-oxalate nuts with a source of calcium, such as dairy, can help bind oxalates in the gut and prevent their absorption.
Safer Nut Alternatives: Lower-oxalate nuts like macadamias, pecans, and walnuts are generally safer choices for people at risk for kidney stones.
Hydration is Critical: Drinking plenty of water remains the most important factor in preventing kidney stones, as it helps dilute urine.
Beware of Salt: Opt for unsalted cashews to avoid excess sodium, which can contribute to kidney stone formation.
Magnesium's Role: Despite their oxalate content, cashews are a source of magnesium, a mineral that can inhibit stone formation; however, supplementation might be a better option.

The Link Between Cashew Nuts and Kidney Stones

Kidney stones are hard deposits made of minerals and salts that form inside the kidneys. The most prevalent type, calcium oxalate stones, form when calcium combines with oxalate in the urine. A primary dietary strategy for preventing these stones is to limit foods high in oxalate.

Cashew nuts are one of the foods on the high-oxalate list. For example, a 1-ounce serving of dry-roasted cashews contains approximately 262 milligrams of oxalate per 100 grams, a substantial amount that can elevate urinary oxalate levels. For someone with a history of calcium oxalate stones, this increase could trigger new stone formation. While cashews offer healthy fats and other nutrients, their oxalate concentration makes them a high-risk food for those sensitive to oxalates.

The Role of Oxalate and Calcium

Oxalate is a naturally occurring compound found in many plant-based foods. In a normal diet, calcium binds with oxalate in the digestive tract, which allows the body to excrete it through feces. This prevents the oxalate from being absorbed and reaching the kidneys. However, when calcium intake is insufficient or oxalate intake is excessive, the unbound oxalate is absorbed and excreted in the urine, where it can combine with calcium to form crystals and eventually stones.

This explains why dietary management is so important. A key strategy is to ensure adequate dietary calcium, which acts as a protective mechanism by binding to oxalate in the gut. Eating a handful of cashews on their own might be riskier than consuming them as part of a meal that includes calcium-rich foods like yogurt or cheese.

Practical Strategies for Managing Nut Consumption

If you have a history of kidney stones but don't want to completely give up nuts, balance is key. Moderating your intake and choosing lower-oxalate alternatives can help. Always opt for unsalted nuts, as high sodium intake can also increase the risk of stone formation by raising the amount of calcium in your urine.

Here are some tips for incorporating nuts into a kidney-stone-friendly diet:

Portion control: Keep servings small, such as a one-ounce portion.
Pair with calcium: Always eat high-oxalate nuts like cashews with a calcium source.
Consider low-oxalate alternatives: Explore nuts with a lower oxalate content.
Stay hydrated: Drinking plenty of water helps dilute the urine, which is crucial for preventing all types of kidney stones.
Consult a professional: Work with a doctor or dietitian to create a personalized meal plan.

A Comparison of Nuts for Kidney Stone Patients


Nut Type	Oxalate Level	Potassium (per 1/4 cup)	Notes
Cashews	High	~180 mg	Best to limit, consume in moderation with calcium.
Almonds	Very High	~200 mg	Should be limited or avoided if prone to stones.
Macadamia Nuts	Low	~124 mg	A safer, low-oxalate option.
Pecans	Low	~101 mg	Another safe, low-oxalate choice.
Walnuts	Low	~129 mg	Low in oxalates and high in heart-healthy omega-3s.
Pistachios	Low	~290 mg	Low in oxalates, but higher in potassium.

The Importance of Magnesium

While cashews are high in oxalate, they are also a good source of magnesium, with one ounce providing about 83 mg. Higher magnesium intake has been inversely associated with the prevalence of kidney stones. Magnesium can inhibit stone formation by binding with oxalate in the gut and by increasing the solubility of calcium oxalate in urine. However, relying on cashews for magnesium intake is not advisable due to their high oxalate content, especially for individuals who are particularly sensitive. Taking a magnesium supplement, such as magnesium citrate, may be a better option for those needing to boost their intake.

The Bottom Line

For individuals with a history of calcium oxalate kidney stones, it is generally recommended to be cautious with cashew nuts due to their relatively high oxalate content. While a small, occasional portion might be tolerated by some, large or frequent consumption could increase the risk of stone formation. The best approach is to focus on lower-oxalate nuts like macadamias, pecans, and walnuts while maintaining a high fluid intake and pairing high-oxalate foods with calcium. A balanced diet, rather than the elimination of all nuts, is the most sustainable approach for managing kidney stone risk. Always consult a healthcare professional or registered dietitian for personalized dietary advice.

Frequently Asked Questions

Yes, cashews are considered to have a moderate to high oxalate content. This means they can increase the risk of forming calcium oxalate kidney stones, particularly in individuals who are prone to developing them.

For those with a history of calcium oxalate stones, moderation is key. Small portion sizes (around one ounce) are generally recommended, and it's best to consume them alongside a calcium-rich food to help reduce oxalate absorption.

Instead of cashews, individuals concerned about kidney stones can opt for lower-oxalate nuts. Good options include macadamia nuts, pecans, and walnuts.

Cashew butter, like whole cashews, is also high in oxalates. If consumed, it should be in small portions and, ideally, with a meal containing calcium. Choose natural varieties without added salt.

The oxalate content in cashews is not significantly reduced by roasting or cooking methods. The primary strategy for managing their intake is through portion control and pairing them with calcium.

For those at high risk of kidney stones, getting magnesium from a supplement like magnesium citrate might be a better option. This allows for magnesium's stone-inhibiting benefits without the high oxalate load found in cashews.

Beyond managing nut intake, prevention includes drinking plenty of water, limiting high-sodium foods, moderating animal protein, and ensuring adequate calcium from food sources. Consulting a dietitian is recommended.