When I was down with a cold as a child, my mom often handed me a bowl of chicken noodle soup to get me back on my feet. I’m not sure whether it actually worked, but I sure believed it would.
Chicken soup and animal broths have long been thought to provide essential minerals and other nutrients to nourish our bodies and minds. And in fact, studies have shown that traditional chicken soup can affect white blood cell activity. Soup inhibited the movement of neutrophils, a type of white blood cell that defends against infection.
These days, broths are more popular than ever. The web is filled with recommendations to drink long-simmered bone broth regularly to heal the gut, improve joint health and boost immunity.
Models are reportedly sipping bone broth for the hair-, skin- and nail-enhancing collagen.
Bone broth reportedly contains a number of amino acids that nourish our bodies from top to bottom, including collagen, gelatin, proline, glycine, arginine and glutamine.
For that reason, popular gut-healing diets such as the Gut and Psychology Syndrome diet (GAPS) and the Specific Carbohydrate Diet (SCD) include bone broth as important steps.
I too have joined the broth brigade for the promise of gut healing.
Thus when I heard about a study indicating broth may have high levels of lead, I wanted to learn more. I set out to set the record straight on this “liquid gold.”
The ‘Lead’ Study on Chicken Bone Broth
First, let’s look at the study that threw the safety of bone broth into question. In 2013, researchers in the UK got cookin.’ Specifically, they made four different combinations of broth:
• Using just boiled tap water
• Boiled tap water with chicken bones
• Boiled tap water with chicken skin and cartilage without bones – from a cooked chicken
• Boiled tap water with chicken meat
They reportedly used organic chicken cooked in the same type of pots (stainless), and boiled each variation for the same length of time.
Here are lead levels in each variation:
• Using just boiled tap water, .89 µg/L (microgram per deciliter)
• Boiled tap water with chicken bones, 7.01 µg/L
• Boiled tap water with chicken skin and cartilage without bones – from a cooked chicken, 9.5 µg/L
• Boiled tap water with chicken meat, 2.3 µg/L
Lead levels with the skin and cartilage came in at more than 10X that of just the tap water, while broth made with just bones showed more than 7X the amount.
But are those lead levels actually high? If we go by government guidelines, then no. The U.S. Environmental Protection Agency (EPA) set its safety threshold at 15 parts per billion (the same as µg/L).
What We Don’t Know
However, the study brings up as many questions as it answers. Where did the chickens come from? What were they fed? What was the pH of the water? How much fluoride was in the water?
The Weston A. Price Foundation points out that water with higher pH can leach more lead, while water with more fluoride increases lead accumulation. Grain feeds could also increase the chickens’ exposure to lead.
But why would there be so much lead in broth? Like calcium, lead in the environment concentrates in bones. Animals used in making broths could be exposed to lead from paints, leaded gas (still used in farm equipment), dust and soil. We know nothing about the environment of the chickens used in the study.
A 2017 Study on Pig and Cow Broth
That 2013 study unfortunately remains the only one I could find that measures metals in chicken bone broth. However, a 2017 study assessed levels in pig and cow bone broths.
The Taiwan-based study used pig legs and ribs from Taiwan, and cow femurs from Australia, boiled for 12 hours.
Here’s what they found:
• The amount of lead in these broths came in at 6.14 µg/L and 7.12 µg/L for pig leg and pig rib bones, respectively, in acidified water (with vinegar added)
• In un-acidified water with pig legs, lead levels were just 2.6 µg/L
• The amount of beneficial minerals such as calcium and magnesium increased with cooking time
The researchers concluded: “…nutritional values, and particularly calcium levels, have attracted attention, but systemic evaluations of methods of their preparation and the range of calcium concentrations are few, as are the health risks associated with the ingestion of toxic metals such as lead that commonly accompany bone minerals.”
Nutrients May Neutralize Lead Absorption from Bone Broth
Other studies indicate that certain vitamins and minerals can help neutralize the absorption of lead. Those include calcium, iron, and vitamins B, C and D. Deficiencies of these can increase lead accumulation in bones and blood.
Studies do not, however, show high levels of any of these in broth. You’ll need to get them from other sources.
Conclusion: I’m Still Drinking Up
Many people report relief and healing with bone broth, particularly those struggling with gut dysbiosis. It allows their digestive systems to heal through these easy-to-absorb nutrients.
In the years that I’ve been around people on the GAPS and SCD diets, I’ve never heard anyone report higher levels of lead in their blood tests. And these are people that are typically testing their various health stats on a regular basis. Of course, that’s not a scientific determination in any way.
But I still believe in the benefits of drinking bone broth. I doubt a mug a day will deliver a toxic amount of lead.
If you’re concerned about lead in bone broth, but still want to enjoy the benefits, here are a few recommendations to monitor and minimize the risk:
• Seek out the highest-quality meats you can. Go with grass-fed meats and wild-caught fish. If you buy from local farmers, ask about their environments. Do they use leaded gas? Are there any possible sources of lead paint?
• Test your blood for lead levels regularly
• Stay well-nourished with nutrients that mitigate lead absorption
- Chicken soup inhibits neutrophil chemotaxis in vitro
- The risk of lead contamination in bone broth diets
- Bone Broth and Lead Contamination: A Very Flawed Study in Medical Hypotheses
- Essential and toxic metals in animal bone broths
- Bone Broth and Lead Toxicity: Should You Be Concerned?
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