*Originally published on 3/14/25. Updated on 4/15/25.
Over the past few months a bunch of people asked us if we tested our bone broth for toxic heavy metals. When we get the same question a lot, we of course look into it.
My first question was --- Is there an issue with toxic metals in bone broth? As it turns out, yes, there "can" be an issue!
Heavy metals are naturally present in our environment. We need the "good" heavy metals to thrive: iron, zinc, magnesium, copper, etc. But, we can 100% do without the toxic heavy metals: arsenic, cadmium, lead, mercury, etc.
Too many toxic heavy metals can lead to a host of pretty awful issues: nervous system damage, cardiovascular issues, cancer, endocrine disruption, kidney damage, and so on.
Our body is designed to excrete heavy metals through urine (and a little bit through sweat, hair, and breastmilk too)... but only so much. There's a limit. If you're overloaded, your body will store those heavy metals in your bones, blood, tissues, and organs.
Similarly, if an animal is exposed to heavy metals via food, water, air, dust, or soil, those heavy metals accumulate in the bones. Maybe the farm's soil or air is contaminated from a nearby factory. Maybe the pipes for the water has lead solder connecting them. Maybe the feed a farm is buying was grown on contaminated soil or processed on contaminated equipment.
And, of course, a main purpose of bone broth is drawing out as much as possible from the bones. If there are heavy metals in bones, they will make their way into the broth. This is especially true when you use apple cider vinegar to draw everything out and make it thick and gelatinous (like our broth).
And that led me to my second question --- Should I be concerned about every bone broth? Where is the fear coming from? Well... it seems it might be a little political.
There was a study done in the UK in 2013 that scared a lot of people. It's titled "The Risk of Lead Contamination in Bone Broth Diets". This study found high levels of lead in organic chicken bone broth, which is quite concerning. And, in fact, this one study is still cited in articles written today!
Let's dig a little deeper. Let's go farther than the short abstract.
Here are the broths tested in the study and their test results for lead:
(9.5 parts per billion): Broth made from tap water plus skin and cartilage(7.01 parts per billion): Broth made from tap water plus bones(2.3 parts per billion): Broth made from tap water plus meat(0.89 parts per billion): Tap water alone cooked for the same amount of time as a control.
But, they only used organic chicken from one farm. And, there's zero information about that farm, their practices, the feed, and the broth recipe. Did they use vinegar or wine in the broth? Was the chicken's water contaminated with lead? What was the quality of the feed and the soil? Were the chickens raised indoors or outdoors? So many unanswered questions! All we get is that it was one "organic chicken" that created a lead issue with broth.
Another curious thing is that the broth with skin and cartilage contained more lead than the broth made with just bones. Bones are where lead is stored, so why wouldn't the broth made with bones only contain more lead? It's an odd result.
Moreover, the abstract of the study specifically called out "bone broth diets" like GAPS and paleo. They even go so far as to write, "In view of the dangers of lead consumption to the human body, we recommend that doctors and nutritionists take the risk of lead contamination into consideration when advising patients about bone broth diets."
That's quite curious. Why are they worried about these diets? Are the researchers anti healing through food? Who funded the research? Is it political?
My opinion? This study is not comprehensive. It does not speak to all bone broths. But it does cover a potential issue if the water or animals are overloaded with heavy metals. And, as we know, our poor planet is becoming more and more contaminated with toxins like these toxic heavy metals 😢
What I glean from this study is that we need more research. We need to stay vigilant and test from time to time. We don't need fear to spread and people to stop drinking broth from this one study.
Regardless of whether the fear was fabricated or legit, we tested our bone broth anyway. After all, it's always nice to validate that your food choices are as clean as you think.
For Miller's, here were my concerns before testing:
What if there's mercury in the fishmeal in our chicken feed?What if the soil that our animals live on is contaminated?What is the well water that the broth is made with is contaminated?What if the Celtic sea salt has lots of heavy metals?
We actually tested twice. As it turns out, the first test results from March had too high a LOQ (limit of quantification). So, we sent new products in April for testing at a lower LOQ.
The results are in! Our bone broth tested A+++ for arsenic, cadmium, lead, and mercury.
You can find the actual Eurofins test results right here!
For easy reference, here's a chart summarizing the results:
You'll notice that, for every sample, the results are "<1.0 μg/kg" and "<4.0 μg/kg".
The "<" indicates the limit of quantification (LOQ), the lowest concentration that can be accurately tested using the test procedure in that sample type. So if a "<" result appears, it means that none of that metal was found in the sample above the specific reporting LOQ. Whether or not they were present below this LOQ is information that's not provided by the test.
It's also important to note that a μg/kg is a part per billion (ppb). So, for 1 μg/kg, in every billion grams of that food, there would be one gram (or 0.0000001%) of that particular heavy metal. This small numbers matter when it comes to toxic heavy metals, since it doesn't take all that much for your body to become inundated and start experiencing issues or damage.
These results are excellent. It means the broth definitely isn't overloaded with toxic heavy metals and are within safe levels.
Our amazing customers mentioned Mike Adams to me numerous times after we released the first set of broth results. Mike Adams is an outspoken consumer health advocate, investigative journalist, activist, and science lab director. It turns out Eurofins, the lab we used, is a lab that he recommends.
Moreover, our results land us in his highest rating when it comes to heavy metals!
I think we're doing pretty great when it comes to providing clean, natural food. But, the results did make me pause.
You might be thinking what I first thought -- "But wait, you got a positive reading for arsenic. Isn't that bad?"
Let's dive in -- Where would arsenic in food come from?
First off, it's important to note that there are organic forms of arsenic as well as inorganic forms. Our body can handle the organic kind pretty well. But, the inorganic kind is carcinogenic. Our test results show the level of all arsenic, and it doesn't divide inorganic and organic.
Second, it was a mystery to me how arsenic had a reading in the ground beef but not the beef bone broth. Thankfully, that has a pretty easy explanation. Whereas lead mainly accumulates in the bones, arsenic accumulates more in the organs and muscles. And, of course, meat is muscle.
It was also quite perplexing how arsenic showed in our beef as well as our chicken. You see, our beef and chicken are grown on two separate farms (hours apart) and are processed at two separate processors (also hours apart). They're fed two completely separate diets, too!
My only explanation is farmland in general or maybe even our environment in general.
Organic arsenic has always been naturally present in the soil and water. It's just there in small amounts. But, levels nowadays are likely higher due to overuse of products laden with inorganic arsenic over time.
Starting in the 1940s, conventional farmers would include drugs filled with inorganic arsenic in the feed for pigs and chickens and turkeys to encourage fast growth and prevent disease. Ugh. This actually led to concerns about arsenic poisoning, and that that practice was banned recently, in 2016. It makes me think that all the agri-waste has contaminated our farmland a bit, perhaps in both the soil and water.
And then of course there are synthetic pesticides and herbicides and fertilizers that may contain inorganic arsenic. And their use on conventional farms might runoff everywhere else.
Now, let's compare our results to food in general. Ours are extremely low.
The data below is based on a few scientific studies:
Arsenic: Rice contains anywhere from 90-450 ppb (that includes that rice cereal for babies, too). Meat and poultry in general typically contain 100-200 ppb.Cadmium: Spinach contains 1117-222 ppb. Rice contains 6-19 ppb. Meat and poultry in general contain about 10 ppb.Lead: Meat and poultry in general contain about 25 ppb.Mercury: The larger the fish, the more time it has to accumulate mercury. Swordfish and king mackerel can have about 1,000 ppb. Meat and poultry in general contain about 10-50 ppb.
Wow! Putting that into perspective, it looks like our broth and meat are quite clean and extremely low in toxic heavy metals!
Are you satisfied with our heavy metal results? Do you think we should take further action? Should we test other products?
Do you worry about toxic metals (or other junk) in your food? Where have your fears stemmed from?
I'd love to hear from you. You can comment below (no account required) or contact us 😊
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Sources
The risk of lead contamination in bone broth dietsBone Broth and Lead Toxicity: Should You Be Concerned?Bone Broth and Lead Contamination: A Very Flawed Study in Medical HypothesesBone Broth, Collagen, and Toxic Metals: A Research ReviewInorganic arsenic toxicosis in a beef herd Consumer Wellness Center Labs Heavy Metal RatingsArsenic in Meat and Animal ProductsInorganic arsenic toxicosis in a beef herdArsenic in brown rice: do the benefits outweigh the risks?A Survey of the Levels of Selected Metals in U.S. Meat, Poultry, and Siluriformes Fish Samples Taken at Slaughter and Retail, 2017–2022Arsenic in your foodDietary exposure to cadmium from six common foods in the United StatesMercury Content in Commercially Available Finfish in the United States Author links open overlay panel
