Can Bone Broth Cause Cancer? The Evidence Explained

No direct evidence links bone broth consumption to cancer in humans. The concern shows up online because bone broth contains trace amounts of substances that, in isolation and at much higher doses, have documented connections to cancer biology: heavy metals like lead, amino acids that tumors rely on, and compounds formed during prolonged cooking. But when you look at the actual concentrations found in a typical serving and compare them to thresholds that toxicologists consider dangerous, the picture is far less alarming than the headlines suggest. The story is more interesting than a simple yes or no, though, because the theoretical pathways are real even if they do not translate into a practical cancer risk from your soup pot.

Lead and Other Heavy Metals

This is the concern that gets the most traction. Bones accumulate lead over an animal’s lifetime, and cooking those bones in water can release some of that lead into the broth. A widely cited 2013 study tested organic chicken broth and found that broth made from bones contained about 7 micrograms of lead per liter, while broth from skin and cartilage reached roughly 9.5 micrograms per liter. Tap water treated in the same way came in at under 1 microgram per liter. So yes, bone broth had several times more lead than the water used to make it.¹

Those numbers sound worrying until you compare them to what toxicologists actually flag as risky. A larger 2017 study that measured lead, cadmium, and aluminum in multiple types of animal bone broths found that a single serving delivers only a few micrograms of lead and cadmium and a few hundred micrograms of aluminum. The researchers calculated hazard quotients (essentially, how close you are to a dose that regulators consider unsafe) and found them to be generally below 0.002, meaning the exposures were hundreds of times below reference limits.² A hazard quotient of 1.0 would be the point of concern. Being at 0.002 is practically negligible.

That does not mean lead is harmless. Lead has no known safe level of exposure, and even small amounts accumulate in the body over time. But the amount you get from a bowl of bone broth is comparable to what you encounter from many other common foods, tap water, and everyday environmental exposure. You would need to consume an enormous volume of bone broth daily for it to become a meaningful contributor to your total lead burden.

How Lead Connects to Cancer Biology

The reason lead ends up in cancer conversations at all is that lead and cadmium are classified as probable or known carcinogens. Their mechanism is indirect but well-documented in laboratory research: rather than directly mutating DNA the way radiation does, these metals interfere with the body’s ability to repair DNA damage. When DNA repair systems are disrupted, errors that would normally be corrected can accumulate, and over time that raises cancer risk.³ More recent research has confirmed that lead exposure can alter the expression of genes responsible for DNA repair.⁴

The critical detail is dose. These DNA repair effects have been studied at occupational and environmental exposure levels far above what a bowl of broth delivers. The jump from “lead can interfere with DNA repair in lab cells” to “bone broth gives you cancer” skips several floors of evidence. It is the kind of reasoning that could indict virtually any food containing trace metals, which includes most foods grown in soil.

Does Prolonged Cooking Create Carcinogens?

Bone broth is typically simmered for many hours, and extended cooking of protein-rich foods can generate compounds linked to cancer. Two categories get attention: heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). Both form when meat is cooked at high temperatures, and both have been shown to be carcinogenic in animal studies.⁵

Here is where bone broth gets a relative pass compared to, say, a charred steak. HCAs form primarily when creatine, amino acids, and sugars react at temperatures above roughly 150°C (about 300°F). PAHs form from the incomplete combustion of organic material, mainly when fat drips onto flames or hot surfaces. Simmering broth on a stovetop stays at or near 100°C (212°F), well below the temperatures where HCA formation accelerates. And since the liquid environment prevents the charring and smoking that produce PAHs, broth-making is a much lower-risk cooking method than grilling, frying, or broiling. The science that connects cooking to carcinogens is real, but it applies far more to high-heat, dry-heat methods than to gentle, wet simmering.

Another category of compounds, advanced glycation end products (AGEs), forms when proteins and sugars react during cooking. Dietary AGEs are associated with increased oxidative stress and inflammation.⁶ While chronic inflammation is a known contributor to cancer development, AGE formation is again driven primarily by dry heat and high temperatures. Liquid-based cooking generates substantially fewer AGEs than roasting, grilling, or frying. Bone broth is not free of AGEs entirely, but it sits on the lower end of the dietary AGE spectrum.

The Glutamine Argument

A more speculative concern involves the amino acid glutamine, which is abundant in bone broth. Cancer cells have a well-documented appetite for glutamine. Many tumor types reprogram their metabolism to consume large amounts of it, using it as fuel for rapid growth.⁷ Laboratory research has even explored starving cancer cells of glutamine as a therapeutic strategy, because transformed cells need much higher concentrations of it to survive than normal cells do.⁸

This has led some people to wonder whether eating glutamine-rich foods could “feed” a tumor. The reasoning has a surface logic to it but falls apart under scrutiny. Glutamine is the most abundant amino acid in human blood, and your body manufactures it constantly. Eating a bowl of bone broth does not meaningfully change your blood glutamine levels in a way that would selectively benefit a tumor. Your liver, kidneys, and muscles regulate glutamine supply tightly. If simply eating glutamine-rich foods fueled cancer, then meat, dairy, eggs, beans, and even many vegetables would all be implicated, because they all supply glutamine. There is no clinical evidence that dietary glutamine intake causes or accelerates cancer in humans. The research on glutamine restriction as a cancer therapy is about pharmaceutical-level manipulation of the tumor’s local environment, not about skipping soup.

Growth Factors and IGF-1

Bone broth contains small amounts of insulin-like growth factor-1 (IGF-1), a hormone that plays a central role in cell growth, survival, and proliferation.⁹ IGF-1 is essential for normal development, but elevated circulating levels have been associated with increased risk of certain cancers in epidemiological studies. The concern is that consuming IGF-1 in food could raise your blood levels and promote cell proliferation that tips toward cancer.

In reality, the IGF-1 in bone broth faces the same fate as most protein hormones you eat: your digestive system breaks it down into fragments before it ever reaches your bloodstream intact. Your own body produces IGF-1 in the liver, and blood levels are regulated primarily by growth hormone and nutritional status overall, not by the tiny amounts present in a serving of broth. The factors that significantly raise your circulating IGF-1 are broader dietary patterns (high calorie intake, high dairy consumption over time) and body composition, not any single food item. While IGF-1 biology is genuinely relevant to cancer research, the trace amounts in bone broth are not a meaningful pathway to increased risk.

Purines, Uric Acid, and Prostate Cancer

Bone broth contains purines, compounds that your body breaks down into uric acid. Most people know elevated uric acid as a trigger for gout, but some research has also explored whether high uric acid levels affect cancer. One laboratory study found that elevated uric acid promoted the growth of prostate cancer cells and counteracted the growth-inhibiting effects of certain proteins called activins.¹⁰

This is an in-vitro finding, meaning it was observed in cells in a dish rather than in people eating broth. The gap between “uric acid promotes prostate cancer cell growth in a petri dish” and “bone broth raises your cancer risk” is enormous. Purine-rich foods include red meat, organ meats, certain seafood, beer, and many legumes. If the purine content of bone broth were a genuine cancer concern, these much richer dietary sources would be far more significant. For most healthy people, the kidneys efficiently manage uric acid levels regardless of moderate purine intake. People with gout or kidney disease already monitor purines for other reasons, but the cancer angle remains speculative.

Protective Compounds in Bone Broth

The discussion so far has focused on what might theoretically be harmful. But bone broth also delivers compounds with documented anti-inflammatory properties, and chronic inflammation is one of the recognized promoters of cancer. Glycine, the most abundant amino acid in bone broth (largely because collagen is rich in it), has been studied extensively for its anti-inflammatory effects, including its ability to decrease pro-inflammatory signaling molecules and reduce markers of oxidative stress.¹¹

Chondroitin sulfate, another component extracted from cartilage and connective tissue during broth-making, also has anti-inflammatory activity. It works in part by reducing the activation of NF-κB, a key signaling pathway involved in inflammation.¹² Chronic activation of NF-κB is implicated in cancer development, so compounds that dampen it could theoretically be protective rather than harmful.

Whether the amounts of glycine and chondroitin sulfate in a bowl of broth are enough to produce clinically meaningful anti-inflammatory effects in your body is a different question, and the honest answer is that we do not know with certainty. The concentrations in broth are lower than those used in most supplement studies. But the presence of these compounds at least complicates the narrative that bone broth is a net negative from a cancer perspective. Any honest accounting has to weigh both sides.

What Epidemiological Studies Actually Show

Direct epidemiological research on bone broth and cancer is essentially nonexistent. No large-scale study has tracked bone broth consumption specifically and measured cancer outcomes. What we do have are studies on broader broth and soup consumption patterns, and the findings lean in a direction that might surprise people worried about broth.

A Japanese case-control study on early gastric cancer found that clear broth intake was associated with decreased risk of the disease.¹³ A large prospective study following over 265,000 people in Japan also found that daily intake of miso soup (a fermented soybean broth) was associated with significantly lower gastric cancer mortality rates compared with people who rarely or never consumed it.¹⁴

These are not bone broth studies specifically, and Japanese clear broth and miso soup differ from the collagen-heavy bone broths popular in Western wellness culture. The point is not that broth prevents cancer. The point is that the existing epidemiological evidence on regular broth-type consumption does not show increased cancer risk, and in some populations it trends in the opposite direction. This is consistent with the idea that any theoretical risks from trace contaminants in broth are too small to show up in population-level health data.

The Mineral Content Reality Check

Part of the bone broth cancer story ties into a broader misunderstanding about what bone broth actually delivers nutritionally. Many people assume that cooking bones for hours extracts large quantities of minerals, including potentially harmful ones. In practice, the mineral extraction is surprisingly modest. A 2024 analysis of multiple broth types found that even the calcium content was minimal, lower than what you would get from the tap water used to make the broth.¹⁵

This matters for the cancer question because it reinforces the finding from the toxicological studies: bones do not release their contents as freely as people imagine. The same slow, inefficient extraction that limits how much calcium you get also limits how much lead or other unwanted metals end up in the final product. The chemistry of bone mineral dissolution works against both the health claims and the health fears.

Persistent Organic Pollutants

Beyond metals, some researchers have looked at whether animal bones and marrow contain persistent organic pollutants (POPs) like PCBs, DDT metabolites, and other industrial chemicals that accumulate in the food chain. A study of semi-domesticated reindeer in Norway measured these compounds in meat, liver, tallow, and bone marrow. Concentrations were generally low and only slightly above detection limits, with the proportion of samples exceeding detection varying widely depending on the specific compound and tissue type.¹⁶

Reindeer in northern Norway are not directly comparable to the chicken, beef, or pork bones most people use for broth. But the study illustrates a general principle: while animal tissues can harbor environmental pollutants, the levels in bone and marrow tend to be low compared to organs like the liver, where the body concentrates toxins. Marrow-rich broth made from conventionally raised animals could contain trace POPs, but the exposure from a serving of broth is a small fraction of what you get from eating the meat itself. If you eat the animal, the broth is not adding a meaningfully different pollutant burden.

Who Should Actually Be Cautious

For the general population, the evidence does not support treating bone broth as a cancer risk. But a few groups have more reason to pay attention to trace contaminant exposure from any dietary source:

• Pregnant women: Lead crosses the placenta, and fetal development is especially sensitive to even low-level lead exposure. This is not specific to bone broth; the same caution applies to lead in tap water, certain imported ceramics, and other sources. Moderate bone broth consumption is unlikely to be a problem, but daily large-volume consumption during pregnancy warrants more thought.
• Young children: Children absorb a higher percentage of ingested lead than adults do, and their developing brains are more vulnerable. Again, the amounts in broth are small, but if a child’s total lead exposure from multiple sources is a concern, the broth contribution is worth noting.
• People with kidney disease: Impaired kidney function affects the body’s ability to clear heavy metals and uric acid. The purine load and trace metals in bone broth could be more relevant for this group than for people with healthy kidneys.
• People undergoing cancer treatment: Some oncologists advise patients to discuss any significant dietary changes with their care team. The glutamine concern, while overblown for healthy people, is at least a conversation worth having if you are on a treatment protocol that specifically targets glutamine metabolism.

For everyone else, bone broth sits comfortably within the range of normal dietary exposures. It is not a superfood and it is not a carcinogen. The trace contaminants it contains are present at levels that toxicological assessments classify as minimal risk, and several of its components have properties that work against rather than toward cancer development. The fear largely comes from taking real findings in cancer biology and heavy metal toxicology and stretching them to a food source where the relevant doses are orders of magnitude too low to matter.

Why This Question Keeps Coming Back

Bone broth occupies an unusual space in food culture. It was heavily promoted during the mid-2010s as a near-miraculous health food, with claims about gut healing, joint repair, and anti-aging. When something gets elevated that high, a backlash inevitably follows, and contrarian claims (it is full of lead, it feeds tumors, it causes cancer) gain traction precisely because they challenge the hype. Both sides tend to cherry-pick from the same body of literature. The proponents cite glycine’s anti-inflammatory properties and collagen’s role in connective tissue while ignoring the modest nutrient extraction. The critics cite lead contamination studies while ignoring the dose calculations that put those levels into perspective.

The underlying science is neither alarming nor miraculous. Bone broth is a traditional food that delivers some protein, some collagen-derived amino acids, small amounts of minerals, and trace levels of contaminants that fall well within what regulators consider safe. The question “can bone broth cause cancer?” is best answered the same way you would answer it for most whole foods: not at normal consumption levels, based on everything we currently know.