Perhaps you’ve been keeping abreast of the bone broth debate? The practice of preparing broths made from slow boiled animal bones and made popular by the GAPS diet as well as many Paleo advocates, has come under scrutiny thanks to a small pilot study that evaluated the lead content of bone broths prepared from chicken. The likelihood of lead leaching out of the bones and into the broth after prolonged boiling is quite high of course, given that, just like us, animals are tricked into thinking it’s calcium, and accordingly store this heavy metal in their bones. This study by Monro et al and published in the journal Medical Hypothesis in 2013, suggests that regular bone broths could contribute significantly to the lead exposure of an individual given the lead content of the 4 samples they analysed:
(i) organic chicken-bone broth: 7.01 mcg/L
(ii) broth from organic chicken meat without bones: 2.3 mcg/L
(iii) broth made from skin and cartilage off the bone of organic chicken: 9.5 mcg/L
(iv) control (tap water): 0.89 mcg/L
This concern is amplified of course if we consider our most at risk populations: children and pregnant women. At least in the case of kids, this is unfortunately likely to be one of the key target groups for the message of ‘daily bone broths’ given their promotion for conditions such as ADHD and ASD etc. The debate that has followed online (see links below to some of the juiciest bits!) suggests the research is misleading for a variety of reasons including that the chicken they used to prepare the broth, while purchased as ‘organic’, was not certified organic. While I concede there may be room for improvement with the methods employed by this study, I think that we need to be careful not to be reflexively dismissive of negative press, and in doing so fail to see the wood for the trees. This criticism of the lack of organic certification by the Weston Price guys seems to be one of those situations.
Commercial animal feeds are ‘ubiquitously contaminated with lead’ according to the industry based document ‘Health Hazards associated with animal feed’, as are some of the mineral supplements often given to animals, so while a chook that’s been raised on a certified organic farm may have a lesser lead load due to reduced or no reliance on these, they would be extremely unlikely to be lead free given that this heavy metal occurs in most Australian soils to some extent.
(https://www.daf.qld.gov.au/plants/agvet-chemicals-and-residues/chemical-residues-and-contaminants/lead-poisoning-in-livestock):
If the counter argument to Monro’s concerning findings is essentially that ‘done the right way chicken broth doesn’t have any heavy metals or other contaminants in it and therefore is without question safe in all quantities for all individuals’, I would have to ask, what planet are these nay-sayers living on? And can I relocate there please, because the fact is this one is polluted and nowhere is entirely safe! Sorry to be a downer, I am actually just trying to be realistic. I’ve read the journal article by Monro and the two key responses from Weston Price and Chris Kresser and I fear in all the reflexive defending we’re not taking on board an important legitimate concern about excessive lead exposure from high intake of these broths.
That doesn’t mean don’t consume or recommend broths but it does mean we should be mindful of this issue and in doing so, always emphasise using the best source meats we can find but know that even this does not make them completely exempt and think closely about how much is really safe in the really young and the pregnant.
Anyway, I encourage you to read all the bits I’ve provided links to here and make up your own minds – but just being reflexively defensive is not the way to handle negative findings…I think 🙂
Monro et al 2013 paper https://www.ncbi.nlm.nih.gov/pubmed/23375414 this is the abstract if you can’t get your hands on the full text give us a hoy! 😉
Weston Price response https://www.westonaprice.org/health-topics/soy-alert/bone-broth-and-lead-contamination-a-very-flawed-study-in-medical-hypotheses/
Chris Kresser’s response https://chriskresser.com/bone-broth-and-lead-toxicity-should-you-be-concerned/