What heavy metals are in bone broth? A guide to risks and safe consumption

October 4, 2025 •

4 min read

According to scientific research, studies have confirmed that bone broth can contain trace amounts of heavy metals, including lead and cadmium, which are known to sequester in animal bones. This raises valid questions for consumers about potential health risks, especially for those who consume it frequently.

Quick Summary

Bone broth may contain trace heavy metals like lead, cadmium, and arsenic, with levels dependent on bone source, animal diet, and cooking time. By sourcing high-quality bones and moderating intake, risks are generally considered low, but proper preparation is key.

Key Points

Lead, Cadmium, and Arsenic: Studies have detected trace amounts of lead, cadmium, and arsenic in bone broth, metals which can accumulate in animal bones.
Source Matters: The primary factor influencing heavy metal levels is the source of the bones; organic, grass-fed animals from reputable sources are preferred to minimize risk.
Cooking Time and Acidity: Both longer cooking times and the addition of acidic agents like vinegar can increase the extraction of minerals, and potentially heavy metals, from bones into the broth.
Varying Research Results: While some older studies reported higher lead concentrations, more recent research suggests levels are generally low and within safety thresholds for typical consumption.
Mitigation Strategies: Choosing high-quality bones, consuming bone broth in moderation, and opting for brands with third-party heavy metal testing are effective strategies to minimize exposure.
Benefit vs. Risk: For most people, the potential benefits of bone broth, such as its protein and mineral content, are likely to outweigh the minimal risk of heavy metal exposure, especially with proper sourcing and preparation.

Unpacking the Heavy Metal Controversy in Bone Broth

Bone broth has gained immense popularity for its purported health benefits, such as supporting joint health and improving gut function. However, a persistent concern revolves around the potential for heavy metal contamination, particularly since bones can serve as reservoirs for toxic substances. Research into this issue has yielded varying results, underscoring the importance of understanding the influencing factors to make informed dietary choices.

The Science Behind Heavy Metals in Animal Bones

Heavy metals, such as lead (Pb), cadmium (Cd), and arsenic (As), are widespread environmental contaminants. Animals can accumulate these toxins throughout their lives via their food, water, and soil, with the bones being a primary site for sequestration. When these bones are simmered for extended periods to create bone broth, the cooking process can facilitate the leaching of these heavy metals into the liquid.

Lead (Pb): Several studies have focused on lead contamination. A 2013 study reported significantly higher lead concentrations in chicken bone broth compared to the control water. Later research, however, found that while trace amounts of lead were present, the levels were generally low and within safety thresholds for typical consumption. The conflicting findings suggest that factors like the animal's source, diet, and environmental exposure play a crucial role.
Cadmium (Cd): Cadmium is another heavy metal that can accumulate in bones and, subsequently, in bone broth. Research indicates that the levels of cadmium found in prepared broths are typically minimal per serving, but like all heavy metals, it contributes to cumulative exposure over time.
Arsenic (As) and Aluminum (Al): Other heavy metals, including arsenic and aluminum, have also been detected in trace amounts during testing of bone broth and collagen products. The presence of these metals is a reminder that the environment from which the animal was sourced is a critical variable in the final product's composition.

What Influences Heavy Metal Levels?

Several factors can influence the concentration of heavy metals in your final bone broth, and understanding these can help mitigate risk.

Source of Bones: The origin of the bones is arguably the most significant factor. Bones from organic, grass-fed, and pasture-raised animals are less likely to have been exposed to contaminated feed, soil, or water, potentially resulting in lower heavy metal content. In contrast, animals from industrial farms may have a higher risk of exposure.
Cooking Time: A 2017 study found that longer cooking times, specifically over 8 hours, led to a significantly higher extraction of minerals like calcium and magnesium. While this is often seen as a benefit, it also implies a potential for increased extraction of heavy metals over time. Some experts suggest shorter cooking times for broth made primarily for flavoring, especially if you are concerned about heavy metals.
Acidity: Adding an acidic component, such as apple cider vinegar, is a common practice believed to help extract minerals from the bones. Studies have confirmed that a more acidic environment can increase mineral extraction, which could also increase the release of any present heavy metals.
Bone Type: Research indicates that different types of bones (e.g., leg vs. rib) and different animal species can affect the extraction characteristics of various metals. For instance, one study found higher lead levels in broth made from chicken skin and cartilage compared to broth made with just bones.

Homemade vs. Commercial Bone Broth: A Comparison


Feature	Homemade Bone Broth	Commercial Bone Broth
Control over Ingredients	Full control over bone source, water quality, and preparation methods.	Depends on the manufacturer; reputable brands are transparent about sourcing.
Heavy Metal Risk	Variable; highly dependent on the quality and origin of the bones selected.	Generally low in trusted brands due to sourcing and testing protocols.
Nutrient Content	Can vary widely based on cooking time, ingredients, and method.	Can provide a consistent nutritional profile, often standardized by the manufacturer.
Convenience	Requires significant time and effort for preparation.	Highly convenient; ready-to-use liquid or powder forms are available.
Sodium Content	Fully controllable, allowing for a low-sodium product if desired.	Can be high in some brands, requiring careful label reading.

Navigating the Risks: Minimizing Exposure

While the risk from consuming bone broth in moderation appears minimal, cumulative exposure to heavy metals can be a concern for frequent consumers. To mitigate this risk, you can take several proactive steps:

Choose High-Quality Bones: Prioritize sourcing bones from organic, grass-fed, or pasture-raised animals, as they are less likely to have accumulated environmental toxins.
Vary Your Diet: Instead of consuming large amounts of bone broth daily, incorporate it in moderation as part of a varied and balanced diet.
Consider Shorter Cooking Times: While longer cooking can extract more nutrients, it may also extract more heavy metals. Balancing the simmering time could help mitigate risk.
Choose Reputable Brands: If opting for commercial broth, seek brands that provide third-party testing results for heavy metals on their website.
Include Meat Broth: Some studies suggest that using meat with the bones, or even making broth from cooked meat without the bones, can result in a lower concentration of heavy metals, especially lead.

Conclusion: Informed Consumption is Key

While bone broth offers various nutritional benefits, including protein, collagen, and minerals, the potential presence of trace heavy metals, such as lead and cadmium, is a valid concern. Scientific research has provided mixed results regarding the extent of this contamination, with the overall consensus being that levels in typical portions are low. The most significant variables influencing heavy metal content are the quality and source of the bones, along with the preparation method. By being a discerning consumer, prioritizing high-quality, ethically-sourced ingredients, and moderating intake, you can enjoy the benefits of bone broth while effectively minimizing potential heavy metal exposure. As always, a balanced diet from diverse sources is the best approach to ensure comprehensive nutrition.

For more detailed information on metal exposure and its effects on bone health, you can refer to authoritative sources like the National Institutes of Health.

Frequently Asked Questions

Studies have identified trace amounts of heavy metals including lead, cadmium, and arsenic in bone broth. Aluminum has also been mentioned in some research.

Heavy metals from the environment, such as contaminated soil and water, are sequestered and stored in animal bones. When bones are simmered to make broth, these metals can leach into the liquid.

Yes, sourcing bones from organic, grass-fed, or pasture-raised animals is a recommended way to minimize heavy metal exposure, as these animals are generally less exposed to environmental contaminants.

Research suggests that longer cooking times can lead to increased extraction of minerals from bones, and this may also increase the leaching of any present heavy metals.

For typical consumption, the heavy metal levels found in bone broth are generally considered low and within safety thresholds. The main concern is cumulative exposure, especially for those who consume large amounts regularly.

For occasional consumers, the risk from heavy metals in bone broth is minimal, especially when using high-quality bones. Concerns mainly apply to individuals who consume it frequently or in large quantities.

Many reputable commercial bone broth brands conduct third-party heavy metal testing and provide results online to ensure product safety. Checking for this information is a good practice for informed consumer choice.