A note from DrKF –
I “grew up” in the laboratory and clinical worlds of functional medicine, where we had a tight, collegial team of curious, committed minds and numerous mentors to guide, support and inspire us. It was without question that I needed to duplicate and grow this rich firmament of my early years when I struck out onto my own. Having been successful in this endeavor, there are many facets to our work today. One of them is research. To me, it goes without saying that we (FxMed clinicians, scientists, industry folks) must try to answer the questions we ask, the hypothesis we form (even as an N = 1 case report, or a small clinical retrospective study), and funnel those findings into the growing body of evidence validating functional medicine paradigm. We have to do this if we aim to alter the trajectory of global health care…
To that end, I want to offer you a simple project we conducted in our clinic, directed by our nutritionist Jill Sheppard Davenport. This is science, but it’s not rocket science. And yes, it did require minimal money, but not a lot. And yes, it was so fun and empowering for us to not just ask (we all do that in FxMed) but to ANSWER. Or start to answer. A very fundamental question many of us have these days:
What is the toxic metal content in different bone broths? (and while we’re at it: What is the essential element content in different bone broths?)
Without further ado, let me turn this over to Jill, supported by our Nutrition Programs Director, Romilly Hodges, and our bone broth research study.
This article was written by our clinic nutritionist Jill Sheppard Davenport MS CNS LDN
Do you drink bone broth? We love bone broth, routinely drink it and recommend it to clients. It’s nourishing, versatile, and contains nutrients that promote gut and joint healing, reduce inflammation, build beautiful skin, bolster immunity, and strengthen muscle mass. Plus, it makes super-tasty soups and stews.
But, while bones are replete with essential minerals and metals, they, unfortunately, can store toxic metals, like lead, too. 1,2
When an unsuspecting broth maker boils bones for a long period of time, the cooking process could potentially release sequestered lead into the water. Does this really happen – does bone broth contain lead? Or, is the concern purely theoretical?
A Quick Primer On Lead
To understand just how much the answer matters, here’s a quick primer on lead. Lead is a well-known neurotoxin. Studies show that elevated blood levels of lead are associated with deficits in growth, learning, and attention among children. Among adults, studies correlate high lead levels with neuropathy, hyperactivity, depression and anxiety.3,4,5 Plus, because essential metals and minerals compete for absorption in the small intestines, exposure through food could lead to deficiencies that affect hundreds of nutrient-dependent biochemical pathways, and even gene expression.6,7 The bottom line? Lead toxicity has consequences for mood, cognition and stress handling, growth and development, thyroid function, neurotransmitters, sex hormones and more.
Some (albeit limited) research shows that lead can be present in animal bones:
- Lead-exposed cows do store it in their bones – one study tested thirteen cows that were accidentally exposed to lead and found elevated blood levels correlated well to accumulation in their bones and other tissues.8
- A sixteen-year retrospective study conducted by the Veterinary Biomedical Sciences Department at the University of Saskatchewan found 525 cases of acute lead poisoning among the 2,060 samples they analyzed from cattle in western Canada. The researchers refer to lead poisoning is one of the “most common” metal toxicities found among cattle in the region 9.
- In Brazil, one study identified both lead and arsenic contamination among cattle and chicken, attributed partly to presence in feed.10
With this in mind, we knew we needed to investigate: We initiated a small-scale experiment, to analyze the lead content in three beef bone broth samples. We also tested one sample of hydrolyzed beef collagen because we know time-strapped foodies and smoothie sophisticates often use it as an alternative to bone broth in beverages and recipes.
And there’s more.
In addition to lead, we measured 36 other toxic and essential minerals and metals in our samples, from calcium to zinc and aluminum to uranium, making this the most extensive profile of both bone broth and collagen powder that we are aware of, published to date. We’re excited to share what we found out and help you make sense of it all.
We sent three blinded bone broth samples and one blinded collagen powder sample – all from beef sources — for testing by Doctor’s Data laboratory in Illinois. They used Inductively Coupled Plasma Mass Spectrometry (ICP-MS), an ideal technology for detecting the lowest levels of minerals and metals in a solution, to test for the presence of essential and toxic minerals and metals in our samples.
The lab tested down to 0.001 parts per million (ppm) – meaning we could detect the presence of toxic minerals that have the potential to be missed by industry standards. For example, Kettle & Fire reports testing metals, as a group, down to 5 ppm and Great Lakes Collagen tests for lead down to <0.10 parts per million.11
In addition to lead, we tested the amounts of 36 other minerals and metals in bone broth and collagen powder.
Sidebar: Understanding parts per million
“Parts per million” measures very low concentrations of a substance in a solution. One part per million equals one part of a substance (such as a toxic metal), compared to a million parts of another (such as bone broth). It is the same thing as saying one microgram per gram which is abbreviated “ug/g.” This is helpful to know as you look at our data.
Let’s imagine what .001 parts per million — the smallest amount of metals and minerals our study detects — looks like, by visualizing corn kernels. One million kernels of corn equals about 1,250 ears of corn – so one kernel among those ears equals about one part per million 12. Now, imagine further dividing that single kernel into 1,000 pieces. One of those pieces equals about .001 parts per million, which is the most precise amount of metals and minerals our study data report.
Our Four Samples:
- Organic, Grass-Fed Store-Bought Broth – store-bought beef bone broth made from the bones of grass-fed and finished, organically raised cows, simmered for “at least 20 hours,” from the Kettle & Fire brand. The company sources bones from midwestern U.S. ranches that follow organic practices, and they use reverse osmosis filtered water, which is not re-mineralized after filtration.13
- Organic, Grass-Fed Homemade Broth – beef bone broth made with bones from grass-fed and finished, organically raised cows, from Nick’s Organic Farm in Adamstown, MD, simmered for 40 hours, to allow for a thorough extraction of minerals and metals.
- Conventional Homemade Broth – beef bone broth made from the bones of conventionally raised cows, simmered for 40 hours. Bones processed by A. L. Beck & Sons Meats in North Carolina, and purchased at a Washington, DC supermarket.
- Hydrolyzed Collagen Powder – beef collagen powder derived from hides of pasture-raised, grass-fed cows from Argentina and Brazil, from the brand Great Lakes Gelatin. Not certified organic; cows are raised according to standards of the American Grassfed Association and the food and agriculture practices required by Argentina and Brazil 14.
Our Preparation Methods:
Homemade Broths – To prepare the two homemade bone broths, we used the ingredients and method in the same basic recipe we share with our clinic patients: 1.5 medium carrots, 2 stalks of celery, a large handful parsley (about ¼ cup, loosely packed), 1 tbs. raw apple cider vinegar, 1/3 medium white onion, 1 garlic clove, salt to taste, 2 lbs. raw bones packed tightly in pot, with filtered, cold tap water to cover bones by one inch. We covered and brought the mixture to a boil, then reduced the heat to simmer, and cooked the bones for 40 hours.
We prepared the broths in an Instant Pot (one of our nutrition team’s favorite kitchen tools), which has a stainless steel insert, using the slow cooker normal/medium setting. Both sets of homemade broth contained visually similar types of bones, including those containing larger amounts of marrow and those that came from joints. Neither set was roasted, or had meat left on the bones.
- Commercial Broth – Kettle & Fire does not make their recipe available. Some of the variation of our study results may be simply due to more or less water, bones or vegetables in the Kettle & Fire broth, compared to our homemade versions.
- Hydrolyzed Collagen Powder – We mixed 1 tablespoon of hydrolyzed collagen protein powder into 8 ounces of water to approximate the concentration one would reasonably drink, stirred the sample well to evenly distribute the powder in the solution, and took a sample of the mixture for the test tube.
- Water – For our broths and the collagen powder solution we used carbon-filtered Washington, DC municipal tap water. We chose this water source to best approximate the result of home-made bone broth made by our average patient (since all our patients are advices on home water filtration). Based on our review of Washington, DC’s Drinking Water Quality Report, and independent lab testing of the Big Berkey filter we used to purify the water, we do not believe our water source contributed in a notable way to the toxic metal content in the samples.15
Ready to see what we found? There is much to share! Get the complete study results here:
Sidebar: The scoop on collagen
Collagen is an increasingly popular protein powder supplement. Many add it to soups and smoothies as a bone broth alternative, or slip it into coffee and homemade gummies.
It’s derived from bones, right? Turns out, when found in supplements, it’s usually not. Bones, tendons, ligaments, cartilage and skin all contain collagen. When we researched source materials, we found that the popular beef collagen powders we looked at (Great Lakes Collagen and Vital Proteins) are made from grass-fed cow hides, not bones 16. The bovine collagen content of the Dr. Axe Multi Collagen Protein is also derived from cow hides17.
So, ours is a study of skin and bones! This helps explain the different metal and mineral profiles of our bone broth and collagen powder samples.
1. Farias, P., Echavarria, M., Hernandez-Avila, M., Villanueva, C., Amarasiriwardena, C., Hernandez, L., … Hu, H. (2005). Bone, blood and semen lead in men with environmental and moderate occupational exposure. International Journal of Environmental Health Research, 15(1), 21–31. doi:10.1080/09603120400018782
2. Silbergeld, EK, et. al. “Lead in bone: storage site, exposure source, and target organ,” Neurotoxicity, 1993, Summer-Fall; 14(203(:225-36.)
3. Verstraeten SV, Aimo L, Oteiza PI. Aluminium and lead: molecular mechanisms of brain toxicity. Arch Toxicol 2008;82:789–802.
4. Center for Disease Control, Environmental Health and Medicine Education, Lead Toxicity: What are Possible Health Effects from Lead Exposure?
5. Bouchard, M., Bellinger, D. C., Weuve, J., Matthews-Bellinger, J., Gilman, S., Wright, R. O., … Weisskopf, M. G. (2009). Blood Lead Levels and Major Depressive Disorder, Panic Disorder, and Generalized Anxiety Disorder in U.S. Young Adults. Epidemiology, 20, S38. doi:10.1097/01.ede.0000362292.40972.3a
6. Bitto, A., Pizzino, G., Irrera, N., Galfo, F., & Squadrito, F. (2015). Epigenetic Modifications Due to Heavy Metals Exposure in Children Living in Polluted Areas. Current Genomics, 15(6), 464–468.
7. Bogdan, G, et. al., “Heavy Metals Acting as Endocrine Disruptors,” Animal Science and Biotechnologies, 2011, 44(2).
8. Bischoff, K., Hillebrandt, J., Erb, H. N., Thompson, B., & Johns, S. (2016). Comparison of blood and tissue lead concentrations from cattle with known lead exposure. Food Additives & Contaminants: Part A, 33(10), 1563–1569. doi:10.1080/19440049.2016.1230277
9. Cowan, V., Blakley, B, Acute lead poisoning in western Canadian cattle – A 16-year retrospective study of diagnostic case records.” Canadian Veterinarian journal 2016 Apr; 75(4): 41-426.
10. Caldas, D., Pestana, I. A., Almeida, M. G., Henry, F. C., Salomão, M. S. M. B., & de Souza, C. M. M. (2016). Risk of ingesting As, Cd, and Pb in animal products in north Rio de Janeiro state, Brazil. Chemosphere, 164, 508–515. doi:10.1016/j.chemosphere.2016.08.130
11. Great Plains Gelatin, Heavy Metals Statement, and Midwest Laboratories Report (4/24/14), accessed 11/1/18 states the following results: lead (<.10 ppm), chromium (<.50 ppm), mercury (<.01 ppm), cadmium (<.05 ppm) and arsenic (< .25 ppm).
12. Preshoff, Kim, TedEd, How to Visualize One Part Per Million, accessed 9/1/18.
13. Company website, and email communication with Kettle & Fire Customer Service, 10/4/18.
14. Company website.
15. According to the District of Columbia, Water and Sewer Authority, 2018 Drinking Water Quality Report: Summarizing 2017 Water Quality Test Results there was <.015 ug/g of lead at the tap, in 119 out of 121 samples tested. This is more than the amount of lead detected in our samples, suggesting that it was either not present in, or filtered out, in the water we used. Other Washington, DC municipal tap water data: 0.0-0.0004 ug/g of arsenic, 7 ug/g of magnesium (average sample), 22 ug/g sodium (average sample). We also looked at the DC Water Service Information Map to determine that the public side pipes for the water source we used are made of copper, and private side pipes are lead. We used a Big Berkey carbon filter to purify the water we used. According to their independent lab testing, this filter removes 99 percent of arsenic, and between 97.5 and 99.9 percent of lead.
17. Dr. Axe Multi Collagen Protein Powder Product Info, accessed 9/1/18. This product contains three types of collagen; one type is derived from bovine hides. This company also sells bone broth powder, which is a different product.