Do Cashews Interfere with Calcium Absorption? Unpacking the Science of Nuts

December 9, 2025 •

4 min read

Cashews, like many other nuts, contain natural compounds known as anti-nutrients that can slightly affect mineral uptake. While often a minor concern for most people, understanding this relationship is key to optimizing your diet and answering the question: do cashews interfere with calcium absorption?

Quick Summary

Cashews contain moderate levels of anti-nutrients, like phytic acid and oxalates, which can bind to minerals such as calcium. The effect is typically minimal within a balanced diet and can be reduced by food preparation methods.

Key Points

Phytates and Oxalates: Cashews contain natural anti-nutrients, including phytic acid and oxalates, which can bind to minerals like calcium.
Minimal Impact: For individuals on a balanced diet, the interference with calcium absorption is generally minimal and not a significant health concern.
Easy Mitigation: Simple preparation techniques like soaking, roasting, or sprouting can reduce the level of these anti-nutrients.
Context is Key: The effect on mineral absorption is most relevant in cases of high cashew intake coupled with low overall calcium or existing mineral deficiencies.
Rich in Nutrients: Cashews are a nutritional powerhouse, providing healthy fats, protein, and essential minerals like magnesium and copper, which offer significant health benefits.
Balanced Approach: Enjoying cashews in moderation as part of a varied diet is the best approach to reap their benefits while minimizing any potential mineral absorption issues.

Understanding the Anti-Nutrient Factor in Cashews

Many plants, including nuts and seeds, contain compounds known as anti-nutrients. These substances have a protective function in the plant but can, when consumed, interfere with the body's absorption of certain minerals. In cashews, the primary anti-nutrients of concern are phytic acid (or phytates) and, to a lesser extent, oxalates.

Phytic acid is the main storage form of phosphorus in many plants. When consumed, it can bind to mineral ions, such as calcium, iron, and zinc, making them less available for absorption in the small intestine. Oxalates also have a similar effect, binding to calcium and forming insoluble calcium oxalate salts.

It is important to note that the term 'anti-nutrient' can be misleading. These compounds are not inherently 'bad.' In fact, studies show phytic acid also possesses antioxidant properties and may even help protect against certain cancers. The potential negative effect on mineral absorption is primarily relevant when a person's diet is heavily reliant on high-phytate foods or if they have pre-existing mineral deficiencies.

Are the effects of cashews significant for most people?

For individuals with a varied and balanced diet, the moderate level of anti-nutrients in cashews is unlikely to cause a significant calcium deficiency. The impact is localized to the specific meal in which the cashews are consumed and does not affect absorption from other meals throughout the day. The body also has some adaptive mechanisms, and over time, individuals who regularly consume high-phytate diets may experience some intestinal adaptation to mitigate the effects.

There have been rare, extreme cases, such as the instance of a patient developing oxalate nephropathy after consuming large quantities of cashews daily alongside a low-calcium diet. In this case, the low calcium intake exacerbated the oxalate's impact by allowing more free oxalate to be absorbed, leading to kidney issues. This highlights that context and dietary balance are crucial.

Reducing Anti-Nutrients to Maximize Absorption

Fortunately, several simple food preparation techniques can significantly reduce the anti-nutrient content of cashews and other nuts.

Soaking: This is one of the most effective methods. Soaking nuts in water for several hours or overnight can break down phytic acid by activating the enzyme phytase, which the nut uses to neutralize the phytic acid during germination. Soaking in warm, salted water is particularly effective.
Roasting: Roasting nuts at a moderate temperature can also reduce phytate levels. This process also adds a pleasant crunch and flavour.
Sprouting: Allowing nuts to germinate slightly after soaking can further degrade anti-nutrients. This process promotes enzymatic changes that make the nutrients more bioavailable.
Pairing with High-Calcium Foods: Consuming cashews with foods high in calcium can help the minerals bind in the gut, reducing the absorption of oxalates. For example, a handful of cashews with a small amount of yogurt can help mitigate the effect of oxalates. The diversity of foods helps balance out any minor mineral-binding effects.

Cashews vs. Other Nuts: A Comparison of Phytic Acid Content

The level of phytic acid varies among different types of nuts and seeds. Cashews have a moderate amount compared to some others, as shown in the table below, which references approximate dry weight percentages based on various studies.


Nut	Approximate Phytic Acid % (dry weight)
Cashews	0.19% - 4.98%
Almonds	0.35% - 9.42%
Walnuts	0.20% - 6.69%
Brazil Nuts	0.29% - 6.34%
Pistachios	0.29% - 2.83%
Hazelnuts	Lower than many others

This table illustrates that while cashews contain phytic acid, their levels are comparable to or lower than some other popular nuts. The impact on mineral absorption is not unique to cashews but is a general characteristic of many plant-based foods.

The Broader Nutritional Picture

Focusing solely on anti-nutrients overlooks the significant nutritional benefits that cashews provide. Cashews are a rich source of healthy fats, protein, and dietary fibre. They also offer an impressive array of minerals, including magnesium, phosphorus, and copper, as well as B vitamins and antioxidants.

These nutrients support various bodily functions, such as:

Magnesium: Essential for bone health and regulating calcium levels.
Copper: Crucial for energy production, brain health, and immune function.
Heart Health: Unsaturated fats in cashews help lower 'bad' (LDL) cholesterol and support cardiovascular health.
Bone Health: Along with magnesium, the phosphorus in cashews contributes to maintaining strong bones.

Incorporating cashews into your diet offers a powerful package of health benefits that, for most people, far outweigh the minor anti-nutrient concerns. The key is moderation and dietary diversity.

Conclusion

While it is technically true that the anti-nutrients in cashews, specifically phytates and oxalates, can interfere with calcium absorption, the effect is generally minor and not a cause for concern for most healthy individuals with a varied diet. The body is capable of managing these compounds, and their impact is confined to the meal in which they are consumed. For those with mineral deficiencies or eating large quantities of anti-nutrient-rich foods, simple preparation methods like soaking or roasting can further reduce their effect. Ultimately, the substantial nutritional benefits of cashews, including heart-healthy fats, protein, and a wealth of minerals, make them a valuable and healthy addition to a balanced diet.

Minerals and phytic acid interactions: is it a real problem for human nutrition?

Frequently Asked Questions

Yes, cashews do contain a small amount of calcium. However, they are not considered a major source of this mineral compared to other food items.

Anti-nutrients are natural compounds found in various plant foods that can interfere with the body's absorption of nutrients, including minerals like calcium. Examples include phytic acid and oxalates.

Soaking cashews does not remove all anti-nutrients, but it can significantly reduce their content. This process activates enzymes that help break down phytic acid and other mineral-binding compounds.

For most people with osteoporosis, a moderate intake of cashews as part of a balanced diet is safe. Consuming cashews in moderation and incorporating preparation methods like soaking is prudent, but entirely avoiding them is generally not necessary unless advised by a doctor.

For individuals susceptible to kidney stones, consuming large amounts of cashews could be a risk due to their oxalate content, especially in combination with a low-calcium diet. However, for most people, moderate consumption is safe.

From the perspective of anti-nutrient content, roasting can be beneficial as it reduces the level of phytates. Both raw and roasted cashews offer significant nutritional benefits, and the best choice often depends on personal preference and dietary context.

To maximize mineral absorption, prepare nuts by soaking or roasting them. Also, consume nuts as a separate snack rather than with a mineral-rich meal, and ensure you have a diverse diet with plenty of fruits and vegetables.