Are Cashews High in Heavy Metals? The Truth About Contamination

November 11, 2025 •

4 min read

Recent studies have detected heavy metals like cadmium, lead, and mercury in cashew nuts, raising consumer questions about their safety. This article investigates the scientific evidence to determine if cashews are high in heavy metals and what you should know to make informed dietary choices.

Quick Summary

Cashews contain trace amounts of heavy metals like nickel and cadmium, but multiple studies indicate the levels are generally safe for moderate consumption. The primary source is environmental absorption.

Key Points

Nickel is a Concern: Cashews can have a higher nickel content than many other nuts, which is a particular issue for individuals with nickel sensitivity.
Low Cadmium and Lead: Multiple studies indicate that cashews generally contain lower levels of cadmium and lead compared to other nuts like peanuts.
Source is Environmental: Heavy metals are absorbed by the cashew tree from the soil, with concentrations varying depending on environmental factors.
Risk is Generally Low: For most consumers who eat cashews in moderation, the health risk from heavy metals is considered minimal.
Best Practices to Reduce Exposure: Choosing cashews from reputable, organic, and certified suppliers can help minimize potential heavy metal intake.

Understanding Heavy Metals in Food

Heavy metals such as nickel (Ni), cadmium (Cd), and lead (Pb) are naturally occurring elements found in the earth's crust. They can also enter the environment through industrial pollution and agricultural practices, contaminating soil and water. Plants, including cashew trees, can absorb these metals from the soil as they grow. While trace amounts are often unavoidable, excessive levels in food can pose health risks due to their potential for bioaccumulation.

The presence of heavy metals in food is a concern for regulatory bodies worldwide, which set maximum permissible limits to protect public health. A key distinction to make is between naturally occurring, bioavailable essential minerals and toxic heavy metals. For example, nuts contain beneficial minerals like zinc, but also potentially harmful metals like cadmium, and the concentration of each can vary depending on the growing conditions.

Cashews and Specific Heavy Metals

Scientific research has identified varying levels of heavy metals in cashews, depending on the specific metal in question. While cashews appear to be relatively low in some, they can contain higher concentrations of others when compared to other nuts.

Nickel (Ni)

Studies show that cashews can contain higher concentrations of nickel than some other tree nuts. For instance, a 2024 study comparing nuts on the Polish market found that cashews had the highest mean concentration of nickel. The nickel content in cashews is particularly relevant for individuals with nickel allergies, as exposure through diet can trigger symptoms. The average nickel content is still usually below established safety thresholds for the general population, but sensitivities must be considered.

Cadmium (Cd) and Lead (Pb)

In contrast to nickel, cashews tend to have lower levels of cadmium and lead compared to some other nuts, such as peanuts. A study published in 2024 found that cashews had the lowest average concentration of both cadmium and lead among the tested nuts. However, another study from Nigeria detected cadmium and lead in cashew nut samples. This variation highlights the importance of geographical location and specific farming practices. For most consumers, the risk from cadmium and lead in cashews, particularly from reputable sources, is considered very low.

Comparison of Heavy Metal Levels in Popular Nuts

The table below summarizes how cashews compare to other common nuts regarding heavy metal content, based on available research.


Heavy Metal	Cashews	Peanuts	Almonds	Hazelnuts
Cadmium (Cd)	Lower levels (<LOQ)*	Highest mean concentration	Moderate levels	Moderate levels
Lead (Pb)	Lowest levels (<LOQ)*	Highest mean concentration	Moderate levels	Moderate levels
Nickel (Ni)	Highest mean concentration	Lower levels	Lowest mean concentration	Moderate levels

* <LOQ = Below the Limit of Quantification

How to Minimize Heavy Metal Exposure from Cashews

For those concerned about heavy metals, particularly nickel, several strategies can help minimize exposure without eliminating cashews from the diet.

Choose Reputable Brands: Sourcing cashews from companies with strong food safety standards and transparent sourcing practices is crucial. Reputable brands are more likely to test for and control heavy metal levels.
Consider Organic: While not a guarantee against heavy metals absorbed from soil, organic certification ensures that harmful pesticides and synthetic fertilizers, which can be sources of contamination, are not used.
Vary Your Diet: Instead of relying on cashews alone, incorporate a variety of nuts and seeds into your diet. This diversification helps prevent the over-consumption of any single food type and its associated heavy metals.
Monitor Overall Intake: The total amount of heavy metals consumed from all dietary sources is what matters most. For individuals with high consumption of many food items known to accumulate heavy metals (e.g., rice, cocoa, certain vegetables), adjusting overall intake may be beneficial.

Conclusion: Moderation is Key

The question of whether cashews are high in heavy metals does not have a simple yes or no answer. While they contain higher levels of nickel compared to some other nuts, their content of cadmium and lead is often quite low. For the vast majority of people consuming cashews in moderation as part of a balanced diet, the health risk from heavy metals is considered minimal.

For those with specific sensitivities, like a nickel allergy, or who consume large quantities of nuts, it is prudent to be mindful of sources and consider dietary diversity. Ultimately, the nutritional benefits of cashews, rich in healthy fats, protein, and antioxidants, should not be overlooked. The key takeaway is to choose quality products and practice moderation, ensuring you can safely enjoy this delicious and healthy snack.

For more information on food safety regulations regarding heavy metals, you can visit the U.S. Food and Drug Administration's (FDA) website.

Frequently Asked Questions

Yes, due to natural environmental factors, all cashews contain trace amounts of heavy metals. The concentration varies widely based on soil composition, farming practices, and geography.

Nickel is often found in higher concentrations in cashews compared to some other nuts. This is a concern primarily for individuals who have a known sensitivity or allergy to nickel.

No. While organic standards prevent the use of synthetic pesticides and fertilizers that can contain heavy metals, they do not guarantee freedom from metals absorbed naturally from the soil. Choosing reputable organic suppliers is still a good strategy.

There is no official guideline for a maximum daily number of cashews specifically for heavy metals, as the risk is low for moderate consumption. Focusing on a balanced diet with a variety of nuts and seeds is recommended.

No, processing methods like roasting do not significantly change the heavy metal content that the cashew has absorbed from the soil. Roasting does, however, neutralize the urushiol found in the shell, which is an irritant.

For the average consumer eating moderate amounts, the heavy metal levels in cashews are not known to cause health problems. However, long-term, high-level exposure from all dietary sources could lead to health concerns, so balancing intake is wise.

To minimize risk, you can choose nuts from reputable brands known for food safety testing, consider organic options, and diversify your diet by not relying too heavily on one type of nut.