Yesterday I became aware of a study published in the journal Medical Hypotheses called “The risk of lead contamination in bone broth diets.” (1) The authors mention that consumption of bone broth may be increasing because it is recommended by advocates of both the GAPS and Paleo diets. It’s well-established that farm animals (and humans, for that matter) can be exposed to lead via food, water, air, dust and soil, and that it progressively accumulates in bone. The researchers wanted to find out whether the bones of farm animals might sequester lead, which would then be released into broth during its preparation.
To find out, they prepared chicken broth (using organic chickens) three different ways:
- using chicken bones;
- using cooked chicken meat without the bones;
- using chicken skin and cartilage without the bones after the whole chicken had been cooked.
In each case the same tap water, cooking utensils, cookware and cooking time was used. They also included a fourth control preparation, where they followed the same procedure but used only tap water heated for the same length of time. The lead concentrations in the four different samples were as follows:
- chicken-bone broth: 7.01 µg/L
- bone broth from chicken meat (without bones): 2.3 µg/L
- bone broth made from skin and cartilage off the bone: 9.5 µg/L
- control (tap water): 0.89 µg/L
As you can see, the levels of lead in bone broth made from chicken bones was a little over 7x higher than the tap water, and a little over 10x higher in broth made from chicken skin and cartilage. As the authors point out, lead has “adverse medical effects on the central nervous system, peripheral nervous system, haemopoietic system, gastrointestinal tract, renal system, cardiovascular system, endocrine system and reproductive system”. In short, too much lead wreaks havoc on every system of the body.
Does this mean it’s time to quit the bone broth? Not so fast.
How Much Lead Is Safe?
The authors of the study express alarm about the “high” levels of lead found in the bone broth preparations they made. However, the US Environmental Protection Agency (EPA) has established a safety threshold of 15 parts per billion (ppb, which is equivalent to 15 µg/L) for lead in drinking water. On their page discussing lead and water, they explain that:
Most studies show that exposure to lead-contaminated water alone would not be likely to elevate blood lead levels in most adults, even exposure to water with a lead content close to the Environmental Protection Agency’s (EPA’s) “action level” for lead of 15 parts per billion (ppb). Risk will vary, however, depending upon the individual, the circumstances, and the amount of water consumed. For example, infants who drink formula prepared with lead-contaminated water may be at a higher risk because of the large volume of water they consume relative to their body size.
If drinking water consistently throughout the day with lead levels of 15 µg/L (ppb) does not pose a problem for human adults (and children with the exception of infants drinking formula), then why would drinking 2-3 cups of bone broth with lead levels of 9.5 µ/L pose a problem? I don’t think it would.
That might be the end of the argument right there. But there are additional factors to consider that may make lead in homemade chicken broth even less of a concern.
The Importance of Nutrient Synergy
There’s no doubt that it’s smart to minimize exposure to toxins as much as possible. But in an environment where toxins are found in foods that also contain beneficial nutrients, we must always balance the benefits of those nutrients against the potential harms of the toxins. What’s more, some nutrients protect against the harmful effects of toxins.
For example, I’ve written on the blog and talked on my podcast about how selenium protects against mercury toxicity in fish. More specifically, the reason mercury is toxic is that it damages selenium-dependent enzymes that play a crucial role in protecting us from oxidative damage. This is why you’ve heard so much publicity about the dangers of consuming fish with mercury. However, what these reports neglected to consider is that if a food you consume contains more selenium than mercury, or if background selenium intake is high, mercury won’t be able to destroy all of your selenoenzymes and you’ll be protected from its toxic effects.
As it turns out, certain nutrients like calcium, iron, vitamin D, vitamin C and thiamin (B1) have a similar protective effect against lead toxicity. These nutrients are abundant in Paleo and GAPS diets, and in the case of calcium, abundant in bone broth itself. Let’s take a closer look at how two of these nutrients, calcium and iron, protect against lead toxicity.
Both animal and human studies have shown that low calcium intake increases the risk of lead toxicity. In one rat study, researchers found that rats ingesting a low calcium diet had blood-lead concentrations four times higher than rats on a normal calcium diet, although the quantities of lead ingested were equal. The mechanisms by which calcium protects against lead toxicity involve complex interactions among lead, dietary calcium, intestinal calcium binding proteins and vitamin D, especially 1,25 D (the active form). (2) In fact, the interaction between calcium and lead is quite similar to that of selenium and mercury: one of the ways lead causes harm is by interfering with the beneficial effects of calcium. Lead is known to mimic calcium in biological systems or to alter calcium-mediated cellular responses, compete with calcium in enzyme systems, impair calcium metabolism, or inhibit 1,25-D-mediated regulation of calcium metabolism. (3) Calcium has also been shown to reduce the absorption of lead in the gastrointestinal tract. (4)
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Studies have also shown that susceptibility to lead toxicity is influenced by nutritional iron status. A study in the early 70s found that rodents fed an iron-deficient diet experienced increased susceptibility to lead toxicity. In humans, low iron status of adults has been reported to increase gastrointestinal absorption of lead. (5) As is the case with the lead-calcium and mercury-selenium interactions, lead has been shown to interfere with iron’s physiological functions. For example, lead inhibits three major enzymes that are involved with the production of heme, the ferrous (iron-based) component of hemoglobin, which is the protein that transports oxygen to the cells and tissues of the body. (Mahaffey) Studies also suggest that insufficient iron intake increases the gastrointestinal absorption and soft tissue concentration of lead. (6)
What about vitamin D, vitamin C and thiamin? Though less is known about how these nutrients protect against lead toxicity, vitamin D appears to modify lead distribution once it has been absorbed, preventing its incorporation into bone. (Cheng). Vitamin C has been shown to have chelating properties which help remove lead from the body. And thiamin (B1) appears to inhibit the uptake of lead into cells and promote lead excretion. (7)
We Are What We Eat — and Animals Are No Exception
It’s also plausible that the diet and living conditions of the animals we use to make bone broth will significantly influence the levels of lead their bones, and thus the broth, contain. Food, water, soil and dust are the largest sources of exposure to lead in farm animals. It appears that cereal grains contribute most to dietary exposure to lead. (8) Although I have not seen any comparative data on this, it’s thus reasonable to assume that pasture-raised chickens who eat a combination of forage and grain-based feed would have lower lead levels than conventionally-raised chickens that eat only grain-based feed.
I hope to have some data that will help answer this question in the coming weeks. Jessica Prentice, one of the worker-owners of the Three Stone Hearth community-supported kitchen in Berkeley, CA, has sent samples of their bone broth in to get tested for lead. They make their broth with pasture-raised chickens, so we’ll have at least one example of lead levels in pastured chicken broth to draw from.
That said, given that the levels of lead in the chicken broth tested in the Medical Hypotheses study were below the EPA established safe upper limit for drinking water, and given the protective effect of several nutrients abundant in Paleo/GAPS diets (and even in broth itself), it seems to me that it’s quite safe to consume 2-3 cups of bone broth per day. This is likely to be even more true if your broth is made from pasture-raised chickens. I recommend Kettle & Fire bone broth as a source of lead-free bone broth.
I’ll continue to investigate this issue and report back if I learn anything that changes my opinion.
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Hey, so did you ever get back the lab results for the pastured batch of broth? I’m curious to know what the results were. Thanks!
I had a hair mineral analysis test done before/after I started consuming organic, pastured chicken bone broth. Before, my lead levels were .1. After 3 months of consuming about one cup a day of homemade bone broth from organic, pastured chickens, my lead levels have increased to .3. They are now on the border of what is considered “acceptable”. I am one of those people who do currently have low calcium and iron so that explains why I am accumulating lead. Never the less, I am cutting back on the bone broth for now.
Why you dont perform normal blood sample analysis? Hair analysis isnt valid method(I will say is flawed method used by people who need something in you to treat)
Levels of minerals in the hair do not correlate with levels in the body.
Laboratory techniques are inconsistent–the same hair analyzed in different labs shows different readings.
There are no known “normal” ranges for minerals in hair, so the numbers given by the lab are nonsensical.
Hair analysis is affected by color, texture, age, exposure to the environment, and a host of other factors, rendering results invalid.
Most importantly, hair analysis has never been proven to help diagnose or treat any disease.
Blood test is not a good way to test lead levels. The best way, in my opinion, is a six hour provoked urine test. This will give you a more accurate result for heavy metals.
For my part, I am concerned about the fluoride content of bone broth and gelatin. Most water is fluoridated unfortunately, and the animals are drinking it. Fluoride collects in bones primarily. The symptoms Moosya describes after taking gelatin (migraine) point to fluoride toxicity.
Jul’s symptoms are also indicative of fluoride issues.
And Marka’s…sorry for all the additions, I just wish I could edit my original post.
Well Chris, I can only hope you are looking into this.
You joking right? Symptom they describe can be caused by so many other condition that only incompetent person will said that they are due to fluoride, moreover if you will go and study fluoride toxicity profile you will be see that this lvl which they are probably exposed cause such symptoms second they will get first other symptoms, in other word you try show your knowledge about fluoride toxicity yet only show lack of knowledge in this topic. P.S Im toxicologist.
You “try show your knowledge about fluoride toxicity” and only manage to show your rudeness and poor grammar.
“only manage to show your rudeness ” because point your incompetence? ” poor grammar.” maybe not all are native US. I learn other languages and english only by myself to understand studies so sorry for my grammar I wonder in how many languages you can speak so freely. I point about your incompetence in this field you dont provide any reasonable arguments only changed topic
So wondering about something and asking questions is proof of incompetence? For your information, I learned the form of fluoride in bones is not likely to be a problem. But at the time I asked, I was seeking the information.
However, the glutamic acid from long cooking of the bones can cause issues for many. Bone broth can also cause problems for those who are histamine intolerant.
Anyway, I am done talking to you, Mr. “You’re incompetent”
“So wondering about something and asking questions is proof of incompetence?” So pointing others that they have fluoride toxicity ” The symptoms Moosya describes after taking gelatin (migraine) point to fluoride toxicity.””ul’s symptoms are also indicative of fluoride issues.” is like you wrote “So wondering about something and asking questions is proof of incompetence?” you dont ask question you point others that they have fluoride toxicity even if they symptoms dont mean that.
“However, the glutamic acid from long cooking of the bones can cause issues for many” glutamatic acid slower aborption with other food like fat or carbs, so again you only show ignoracne talking about thing where you dont have knowledge.
” Bone broth can also cause problems for those who are histamine intolerant.” wow best arguments, guess what everything in what someone has allergy will be cause problem to this person..
“Anyway, I am done talking to you, Mr. “You’re incompetent”” typical reaction from person without any arguments.
You are a intoxicated MD
with your toxi-
cology title , keep studying and you’ll find
how wrong you
I just made bone broth using frozen local grass fed lamb bones which I simmered for 48 hours. I have 3 questions:
1. I made mine in an super large enamel coated steel canning pot – was this a safe cooking vessel choice?
2. It was so delicious I drank 3 or 4 cups of it in the first two days… however, I had an unexpected reaction of a headache, congestion and upset tummy after the 2nd day. I’ve since read that slow cooking the bones can cause a build up of histamine and MSG in them to which people with histamine intolerance (not that I ever thought I had one) will react. For this reason, I read in a few places, it is advisable for people rebuilding their guts, to start with shorter term cooking times (4-6 hours) and meat stocks and to avoid bone broths cooked for prolonged periods due to the histamine issue. Has anyone else heard of this? I’m bummed as I have 3 huge yummy containers of my beautiful broth in the freezer and fridge that I might not be able to use.
3. This will probably sound strange, but the bones were so soft, I ate several- thinking it was the same as when I eat wild red salmon with the bones included… perhaps the bones had lots of toxins in them that are causing my reaction?
An enamel-coated steel pot should be okay for making broth/stock. That said, I fail to understand why anyone would cook animal bones for two days since the idea that additional nutrients become available this way has recently been debunked. More likely, by ingesting softened/dissolved bones, you’re also ingesting whatever toxins and/or heavy metals the animal acquired during its lifetime. Although probably not a significant amount in most cases, it might not be the healthiest idea. Good nutritious broth, made with raw meat-on bones and root veggies, shouldn’t take any more than 3 to 4 hours.
My joints have improved since drinking 12/1 cup beef broth per day; however, two weeks ago i developed terrible inflammation and pain along the outside of my knees…not within the joints but along exterior area in the tendons. Any comments?
I am replying to myself to correct the 12/1 cup to 1/2 cup broth.
Maybe you just need to add some boron to your diet.
The reason for your headaches from bone broth can be for the following reasons:
– Firstly, you have an overload of bacteria, viruses, fungal infections in your body that may include candida , h pylori etc. Which you haven’t been able to detect. the moment you eat something so high in nutrients such as bone broth, some sort of chain reaction sets out causing you these migraines and itches
Solution: You HAVE TO DO A COLONIC CLEANSE and a FAST on Juices for atleast a month. Also look into MMS . I have used it and people say its toxic but bull shit to that .. It helped me clear out a lot of shit in my body
– Please check your sugar levels once you have had bone broth. Sugar level spikes can cause lots of troubles
– Finally go and get yourself a blood test for the following . LEAD CONTENT, ARSENIC CONTENT, CALCIUM LEVEL and other heavy metals including mercury etc. Bone broth has lots of lovely calcium and collagen etc.. but also the bones leach out metals that the animals may have been exposed to. The longer you boil the more is leached into the broth and it may be affecting you in some way
Apart from this I cannot pinpoint any other possible reasons apart from stating the worst ones( which i dont wish to name as it will offset panic)
I hope I have been helpful
Do you know if this study tested commercial chickens that are fed arsenic containing chicken feed or if they used pastured chickens?
More media hype telling everyone that they will get lead poisoning from bone broth. I say drink up! Its healthy and delicious! I dont even bother making it though I get mine from a company called Au Bon Broth Bone Broth. Delivered straight to my door and organic. No more mess from cooking!
Media hype? Since when are the results of a peer reviewed scientific journal “media hype?”
Yes, Yes, Yes. Tell everyone that they will get lead poisoning from bone broth. That way all the stupid hipsters driving up the price of this delicious peasant food will move on to drive up the price of some other new food fad.
Chris, this article, though informative, feels like it’s designed to waste people’s time. Before seeing this headline, I didn’t think lead in broth was an issue. After a couple minutes of reading, I’m now convinced I was justified in never having that worry to begin with. Keep striving for that career in Yahoo news. Click bait, though some of the higher quality click bait I’ve seen, I must admit. Thank you for the science.
I’d say he did a job well done if you are now more secure in your thoughts on lead levels in food. He used science to confirm something you were already curious about.
I totally agree…I was wondering about this and feel better knowing someone who seems impartial took a closer look..
Actually I have been wondering whether the lead was an issue. I’m glad he posted it the way his did, otherwise I would not have found it.
Why be nasty? You have something better to add?
Hello from Denmark 🙂 Do any of you get headache from meat broth??? I have leaky gut and a mild histamine intolerance….also sensitive to gluten and dairy. My Health i getting worse and worse even though I eat more and more healty. Then i read then all these symptoms could come from leaky gut (the root of the problem) and of course I want to try to heal this. I tried bone broth, but got headache and irretatet skin….i was schratching my skin so hard that i got sores. Then I tried only simmering for 2 hours (organic chicken) with lots of vegetables also. I just poured a cup of this broth. A mild headache again…can almost feel a small lightning pain i my brain after each sip. What to do???????
Jannie, make sure that you do not make the broth in a toxic pot.
And generally concerning health issues, here is a relevant page in Danish: http://lagorcerocks.com/stenalderkost-pa-ferien-kursted-i-sydfrankrig/ 🙂
Hi and thank you for your response 🙂
I use a normal large Soup pot from a good Danish brand (raadvad). It is made of steel.
I was thinking about the levels of histamine, can they be to high even if I dont let the broth simmer for more than 2 hours (chicken) or 4 hours (organic beefbones).???
I really dont know where to start healing the leaky gut and all the other symptoms….it seems that I can not eat/drink anything 🙁
Then I guess it can’t be the pot …. and perhaps it is indeed the histamines.
I suggest you have a look at GAPS and also ask questions in the GAPS Kids Facebok group – there are a lot of very experienced parents there, who have or are in the process of healing their childrens’ leaking guts. Lots of help and info there.
Yes, probably histamines. Try the gaps diet and try a few days of fasting. If you cant Have bonebroth supplement with collagen, calciumn, magnesium and glutamin. you can also look up dr. axe website for a general overview on how to heal leaky gut. he also recommends GAPS.
did you make a stool test? try to find out if you have an infection or dysbiosis you need to fix that as well…
Janenne I think the problem might be that you are not cooking it long enough. Chicken bone should cook for 24hrs straight, Beef Bones 48hrs. You must cook this long in order to get all the nutrients out of the broth. Also be sure you are skimming the top for impurities. Wellnessmama has a fantastic recipe for broth. Worth goggling.
Hi Jannie, I recommend you getting in touch with Matt Stone at 180degreehealth.com who has helped many people in your situation who are running out of things to eat. He also has a book ‘Diet Recovery 2’ which you may find helpful. Good luck
I am such a believer in the Metagenics product line. I recommend finding a participating doctor (generally a chiropractor or naturopath) that is trained on the products. This site should provide you with a list and some info on the products. http://www.metagenics.com/products/health-categories/gastrointestinal-health
Have you read GAPS – Gut and Psychology Syndrome? Leaky Gut is treatable and the book will explain why you might be having adverse reactions to broths. Good luck x
Hello Jannie – here are a couple of articles that you may find useful
I also seem to have the same problem. I am allergic to most of the things. It all started with lactose intolerance about 10 years ago and within 2 years I was alergic to most of the foods like – milk, greens, few vegetables, some fruits, grains, rasins etc….I mean I cant have anything other than some rice and a few vegetables and fruits. Wondering if you had any luck with GAPS diet?
There are a couple Paleo style books that I have that really get into all the foods that can cause trouble and help with where to start with an elimination type diet. One is The Paleo Approach http://www.thepaleomom.com/about-the-paleo-mom/sarahs-books
The other is Digestive Health with Real Food http://radicatamedicine.com/books-publications/
You might fine one of these helpful.
Can anyone tell me if it’s possible for stainless steel pot to leach metal into the broth, esp, since there is acidity from the vinegar in the broth? Many thanks!
Don’t think so Anna, SS pots of any reasonable quality should be completely non-reactive. This is why surgical instruments and prosthetics installed in the body use stainless.
Clay, enamel and glass are also non-reactive. You have good options for boiling braising roasting and stews.
Thanks so much for this, Jonas! Appreciate the clarification 🙂
Yes, stainless steel does leach into your food. I am having a nickle reaction and that is the one things I can’t use. Vegetables also cause my rash so you might check into that. Not much out there on Nickle allergy but you can’t eat much but meat and potatoes.I’m still trying to find out more.
Yes, cooking with a stainless steal pot leaches nickel into the water. I switched to glass pots and plastic cutlery and it made a huge improvement!!!!! My effects from nickel are extreme fatigue, nausea, among other things. Drinking bentonite clay has helped chelate the nickel out of my body. Now working on the leaky gut and candida, and I believe that Celiac is my root problem. Blessings to all reading this. God bless, John 3:16
Jannie: Have you looked into mercury toxicity from amalgam fillings? That is if you have them or have had them in the past, or had some removed and replaced with with white without the correct protocol being used for your safety. There are various way of becoming toxic – teeth, vaccinations, food, air. Mercury can lead to leaky gut problems. You have to eliminate the source and get the mercury out of your body before your gut will heal. There is a lot of info on you tube about mercury toxicity.
Then look into calcium bentonite clay for detoxing. I found a lot of info at aboutclay.com and have learnt a lot from this site. I am in the process of a clay detox and amalgam removal.
Only just mentioning this incase it is new to you. Hoping that maybe this could help you gain your health back sooner rather than later.
its common problem in our family as after every chicken broth we found that we have headache and our grandma expained it like that: if you prepare the broth from rooster your head always feel ache, but hen broth is good without any headaches
And here’s where bone broth reveals a catch 22 while yes it does heal leaky gut it also will exacerbate a histamine intolerance 10 fold. Histamine intolerance is caused by leaky gut. Histamine intolerant people CANNOT eat slow cooked protein if you still can and are able to eat meat with a histamine condition it must be super FRESH and eaten IMMEDIATELY after cooking the longer meat sits the more histamine it releases hence why you are worse now after eating the broth. STAY AWAY from bone broth ….it’s sad because it is so nutritious but for people with a histamine intolerance it’s HORRIBLE!!!
Excellent analysis once again ! Chriss
Ups, my previous comment “Excellent analysis once again, Chriss” ! got inserted in the wrong place.
To Dani Page, I would like to ask, if you have any references to you statement that “Histamine intolerant people CANNOT eat slow cooked protein – since the longer it cooks/sits the more histamine it releases” ? I seriously doubt you will find any scientific backing for your claim ! I think people in general should be more careful giving advices based on ideas !
Many times when you try a new twist in your eating habits, your body “detoxifies” and you actually feel worse, and get headaches as well, that is not say that your not having an allergic reaction, I would say keep a food diary, and carefully keep track of the reactions you are having, but continue what you are doing, if over time these symptoms get worse than of course discontinue, but if they start to subcide than more than likely you are going through the detox phase.
Jannie, I would suggest trying a probiotic for several months. I use to have a problem with all foods high in histamine and would get really bad headaches along with other side effects. After being on acidophilus for 3 months, all of my problems went away and I rarely get headaches. I do still avoid leftover pork and chicken but other than that I can eat anything.
I would research headaches and detoxing. Many people get them when juicing.
For leaky gut try the Metagenics product called GI Sustain.
Have you considered whether you have a fungal or parasite infection. Significantly likely if you have leaky gut and The itching skin may be a tell tale sign. Nikki
Sorry to hear that you have a leaky gut. I am new to making bone broth so I am not that experienced yet. There may be something else that can heal your leaky gut which I consume everyday and it is called “Kefir”. You can just buy the live Kefir grains on ebay, from a reputable seller, and make your own Kefir and drink it daily. This is 100 times better than any probiotic you can buy at a health food store. All you need is Kefir grains and organic milk. Start out slow with just 1/4 cup per day and work your way up. This is the best probiotic you can drink. Research it the health benefits are amazing. I hope you can figure out a way to continue to drink bone broth but if you can’t consume it, Kefir will help you. Good luck to you Jannie
A lot of the stuff that’s getting posted here is simply heresay, someone read this or someone told someone. Or someonek heard something, a lot of posters are like blindfold people walking through a minefield. No science to back up any suggestion, it’s like the diderence between medical science and religious superstition, if you’re not 100 PC sure don’t bother posting stuff
Jannie are you taking probiotics?
What type vessel was the broth prepared in? One needs to do a search on crock pots.
look into slow cooker liners
I guess to protect from contaminants in food we cant eat. To protect from contaminants in the air we can’t breathe. To protect from contaminants in water we can’t drink. Doing any of these will lead to death. So avoiding contaminants completely leads to death. You can’t avoid all contaminants, because that is a part of being alive. Just enjoy life, do what makes you feel healthy and strong and avoid stress by not worrying about every fricking possibility because stress isn’t good either. I could sit in my home everyday, staring at the sky through the window because there is a possibility that an airplane might land on my house, but would that be living?
Best comment and advice EVER 🙂
Hyperbole for the win!!!
I have recently (as in the last 5 or 6 days) started drinking bone broth each day. I usually drink a big coffee mug of it when i get up and another before bed. I don’t feel much different other than he fact that I’m sweating almost non stop. My normal activities (Chasing around a 1 1/2 yr old) make me sweat PROFUSELY!! My hair and shirt will be soaked by the evening. I havrnt felt sick…just..puny. Is this normal?! Anyone else experienced this?
Toxins coming out maybe.
I’ve started taking bone broth and I’m sweating like crazy too. I would love to find out why this is.
My oldest daughter had lead testing when she was a year old and it was OK. When their levels tested high per blood test we had no other explanation. We never lived in an old house. Their school was not old. They did not mouth toys. the gaps diet was the only thing new. I will never know for certain but bone is a storehouse for lead.
Old houses are not the only source, I am afraid. WebMD writes:
“Here’s what is surprising: pipes in very new homes are potentially a greater risk for lead. Some plumbers still use lead solder to join copper pipes, which exposes the water directly to lead. The risk is highest in houses that are less than five years old; after that, mineral deposits build up in the pipes that insulate the water from the lead in the solder. According to the EPA, you should assume that any building less than five years old has lead-contaminated water.” – find more at http://www.webmd.com/children/environmental-exposure-head2toe/lead?page=3
And perhaps there were old houses, where there are now new ones:
“Lead in soils and dust in the environment has been, and will continue to be, a source of lead poisoning. The sources include flaking, chipping, or weathering paint: improper renovation of buildings and disposal of building materials; lead by the side of roads that has settled out from burned leaded gasoline; settled dust from industrial sources and lead around houses from lead paint that has been scraped off during the continuing repainting of the house.” – from “Lead Contamination In Our Environment”, by Carolyn Kinder at Yale-New Haven Teachers Institute.
Other sources include (from http://www.mayoclinic.org/diseases-conditions/lead-poisoning/basics/causes/con-20035487 ):
“Pottery. Glazes found on some ceramics, china and porcelain can contain lead that may leach into food.
Toys. Lead is sometimes found in toys and other products produced abroad.”
and also note that:
“Lead was also once a key ingredient in paint and gasoline and is still used in batteries, solder, pipes, pottery, roofing materials and some cosmetics.
There is also still leads in te exhaust of cars, see for instance:
“Lead emissions from road transport in Europe: a revision of current estimates using various estimation methodologies.” – Sci Total Environ. 2009 Oct 1;407(20):5367-72. doi: 10.1016/j.scitotenv.2009.06.027. Epub 2009 Jul 21. – text at: http://www.ncbi.nlm.nih.gov/pubmed/19625074
And then there is all the lead accumulated before gasoline became “unleaded”; see:
“Lead Concentrations, Isotope Ratios, and Source Apportionment in Road Deposited Sediments, Honolulu, Oahu, Hawaii”, by R. A. Sutherland, J. P. Day, J. O. Bussen, in Water, Air, and Soil Pollution January 2003, Volume 142, Issue 1-4, pp 165-186.
All that said, it is obvious that lead is everywhere and that it can accummulate in bones. That means that where the animals roamed and found their food is indeed important, but proximity to major roads, building sites, sites of old houses, new plumbing with lead soldering, various kitchenware and utensils are just as likely – and for what concerns most people, probably more likely – sources of lead contamination.
We live in a dirty world and lead in animal’s bones has to coe from somewhere – and think about it: Who is usually more directly exposed to lead in the environment, a grass-fed cow in, say, Montana or a child in a city criss-crossed by roads?
What kind of testing did you do? From Dr. L. Wilson (http://drlwilson.com/ARTICLES/POOR%20ELIMINATOR.htm), it is known that some toxic substances were not expelled until some major improvement of the diet, when the organism gets enpugh force to detoxify and to show these hidden substances in the analyses. So, don’t be desperate: many tests don’t mean exactly “the more lead – the worse”.
If drinking water consistently throughout the day with lead levels of 15 µg/L (ppb) does not pose a problem for human adults (and children with the exception of infants drinking formula), then why would drinking 2-3 cups of bone broth with lead levels of 9.5 µ/L pose a problem? I don’t think it would.
We have to drink water. The lead level will be 24.5 if we drink 2-3 cups of bone broth on top of the drink water. Is it a problem?
Where is the foretold follow up data on this?
Buy Whole Organic Chickens and/or Find a Farmer in your area, make sure he/she keeps their chickens healthy. Use SPRING WATER and ORGANIC Veggie when making the broth. STOP reading articles from this guy.
I wonder how it was prepared, many slow cookers are made in China and have lead in the glaze.