Thursday, March 7, 2013

Paleo and WAP Alert: The risk of lead contamination in bone broth diets

The risk of lead contamination in bone broth diets

This article lies behind a paywall, so I have not gotten a copy of it yet, but here is the abstract:

"The preparation and consumption of bone broth is being increasingly recommended to patients, for example as part of the gut and psychology syndrome (GAPS) diet for autism, attention-deficit hyperactivity disorder, dyslexia, dyspraxia, depression and schizophrenia, and as part of the paleolithic diet. However, bones are known to sequester the heavy metal lead, contamination with which is widespread throughout the modern environment. Such sequestered lead can then be mobilised from the bones. We therefore hypothesised that bone broth might carry a risk of being contaminated with lead. A small, blinded, controlled study of lead concentrations in three different types of organic chicken broth showed that such broths do indeed contain several times the lead concentration of the water with which the broth is made. In particular, broth made from skin and cartilage taken off the bone once the chicken had been cooked with the bones in situ, and chicken-bone broth, were both found to have markedly high lead concentrations, of 9.5 and 7.01μgL−1, respectively (compared with a control value for tap water treated in the same way of 0.89μgL−1). 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."

Seems we may need to add "increased risk of lead accumulation" to the list of dangers associated with eating bone-broths in primal,  paleo, and Weston A Price Foundation diets. 

10 comments:

Charles Grashow said...

The study refers to bone broth from chickens. Were the chickens pasture raised or from a conventional farm? The abstract doesn't say.


http://chriskresser.com/bone-broth-and-lead-toxicity-should-you-be-concerned

"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."

Healthy Longevity said...

So the broths are being supplied by the supplier of the product and Chris Kresser is to report the results. Wow I am sure that there will be sufficient blinding and no conflicts of interest involved in this experiment! This coming from someone who says that it is a “lie that high cholesterol causes heart disease” and that “Eating saturated fat doesn't raise cholesterol levels in the blood”.

Charles Grashow said...

@Healthy Longevity

Why not wait for the results first

Frank said...

Charles

Out of curiosity, what are the abundant nutrients with protective effect in the paleo diet that Chris talks about? Do you know what he is reffering to specifically?

Sagar Bansal said...

"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"

Father Nature said...

Charles, the results are already in. Chris announced them on FB on Feb 21st.

"Update on lead in bone broth: a local Weston A. Price-inspired food co-op sent their pastured chicken/beef broth to be tested for lead, and the levels were undetectable. This is only one example, but it suggests that lead levels may differ in broth made from pastured vs. conventional meat."

https://www.facebook.com/photo.php?fbid=515303601855241&set=a.346979575354312.107082.212758788776392&type=1&theater+

Charles Grashow said...

Jennifer Knoepfle The method detection limit (MDL) is 10 ppb or ug/L, for the two broth samples. This means that that analytical results are not detected at or greater than 10 ppb. Could be any result between less than 0 to 9.9 ppb. If I remember correctly, wasn't the other bone broth at 9 ppb?
February 21 at 8:06pm via mobile · Like · 1

Chris Kresser L.Ac Yes, that's true. I should have been more precise in my description. But I think that all of the factors that contribute to lead contamination are more likely to be present on conventional farms than pasture-based farms.

SO - it's going to depend on where the chickens are raised with regard to the lead they are exposed to.

Question - can't the same thing be true for fruits and vegetables - would not they have concentrations of lead in them that they absorb from the soil regardless of whether or not they are organic?

Charles Grashow said...

SmartEaters Good to get this Chris. Thanks. Although not so sure how you conclude the pastured V conventional bit ... Isn't it at least as likely that local environmental factors, which could pertain at either a "pasture" or a "chicken lot" are the determinant? Lead from industry, traffic, paints, polluted water table etc. could be present just about anywhere right? The relevant bit is that chicken bones appear to concentrate any ambient heavy metal poisoning that may pertain in the environment of the given chickens, in much the same as top feeding fish serve to concentrate mercury but again only in waters already polluted ...

George Henderson said...

You would only have to consume 10X as much tap water as bone broth to equal intakes in the study (obviously at least 10% of the lead in the broth came from the tap water used to prepare it; perhaps much more as bone broth is boiled for a long period and the liquid may reduce and be replaced, unless a pressure cooker is used).

Contamination of fruits and veges with lead is indeed something that the FDA monitors.
the FDA states that "lead levels in juice above 50 ppb may constitute a health hazard".

http://www.fda.gov/Food/FoodSafety/Product-SpecificInformation/FruitsVegetablesJuices/ucm233520.htm

Lead poisoning - if that is what this is, which it's not - is preventable or treatable with zinc, iron, calcium, B6, C, and other nutrients that WAPFers are well supplied with.

Feed normal trace amounts of lead to a spindly vegan, on the other hand, and there might well be another item to add to the "list of dangers".

Don said...

Seems that some people failed to read the abstract carefully, as it contains this sentence:

"A small, blinded, controlled study of lead concentrations in three different types of organic chicken broth showed that such broths do indeed contain several times the lead concentration of the water with which the broth is made."

This was a study of organic chicken broth, not conventional.

"You would only have to consume 10X as much tap water as bone broth to equal intakes in the study ..."

That's supposed to be an argument in favor of the broth?