Here's an interesting comment that Chris Kresser wrote on a article about copper toxicity and confusion. The article can be found here: http://freetheanimal.com/2015/11/practitioner-confused-overload.html:
Chris Kresser states:
"Serum copper values are just a starting point, and should never be used in isolation to make a diagnosis. If serum copper is elevated or decreased, other markers like ceruloplasmin, 24-hour urine copper, AST/ALT, and less commonly, liver biopsy, to further clarify the diagnostic picture.
In the same way, it's a mistake to assume that elevated ferritin is always caused by iron overload. Ferritin, like ceruloplasmin, is an acute-phase reactant which is increased in the inflammatory response. Unfortunately few practitioners understand this and will often diagnose iron overload solely on the basis of high ferritin.
This can all be avoided by running a comprehensive blood panel instead of testing isolated markers. That's exactly what we do for every patient that walks through our door. High serum copper masking iron deficiency? If there is iron deficiency, that will show up in UIBC, TIBC, serum iron, iron saturation, ferritin, and soluble transferrin receptor values, all of which we routinely test for.
So, while serum copper is unreliable as an isolated marker (as is the case for ferritin, and in fact just about any marker), that doesn't mean that it's "worthless", nor does it mean that high serum copper levels may indicate copper toxicity, nor does it mean that elevated copper in relation to zinc is not a clinical concern.
It is well-established that the toxic effects of certain metals can be either synergistic or additive, depending on the metals. For example, this study showed that >20 years of occupational exposure to copper, copper-lead, and copper-iron was associated with higher risk of Parkinson's disease (http://europepmc.org/abstract/med/10385887)—but the odds ratio was significantly higher for the combos than it was for copper alone.
This study suggests that pro-oxidant copper ions affect glutathione in several ways, which in turn potentiates the effects of mercury toxicity. http://www.sciencedirect.com/science/article/pii/S0300483X00003310
This study reviewed the synergistic effects of multiple heavy metals and found that copper has a strongly synergistic toxic effect with other metals, especially cadmium. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.466.9494&rep=rep1&type=pdf
There are many studies indicating that the zinc-copper ratio is altered in various disease states, including autism spectrum disorders (http://www.tandfonline.com/doi/abs/10.1080/13547500902783747), coronary heart disease (http://europepmc.org/abstract/med/19097489), rheumatoid arthritis (http://www.ncbi.nlm.nih.gov/pubmed/26450515), and colorectal cancer (http://www.ncbi.nlm.nih.gov/pubmed/26329996) to name a few.
Of course these are all inflammatory conditions, so it's difficult to know whether the observed copper elevations are cause, effect, or both. But this study found that copper was elevated *without concurrent iron deficiency or excess* in patients with Alzheimer's disease (http://www.ncbi.nlm.nih.gov/pubmed/26401693), and the authors speculated that alterations in zinc/copper levels may be implicated in the pathogenesis of AD.
For these reasons I maintain that serum copper levels, and serum copper zinc ratio, is still a useful indicator—provided that practitioners understand the limitations and do not make erroneous assumptions about causality.
The podcast of mine that you linked to was from 2012. I've learned a lot about metal toxicity since then, and if I could go back in time I would change the title to "Could copper-zinc imbalance be a sign that you're sick", or something along those lines, to make it clear that higher copper-zinc ratio is an indicator and doesn't always suggest that high serum copper is the cause of the problem."
In other words, is copper-zinc imbalance the cause of your sickness or is it a sign that you are sick?
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