11 replies to this topic

[tfor]

I recently read an article which basically said that zinc is totally neurotoxic.

I was really surprised by this. I always thought that taking zinc is important for all kinds of things.

Now I don't know if I should keep taking zinc.

I was also tested for something called Kryptopyrroluria. It's a condition where the body excreeted too much zinc and B6, as far as I understand it.

But many doctors say that this condition isn't real. So I'm not sure what to think.

However, the "therapy" for Kryptopyrroluria is taking high doses of zinc and B6. But now I worry about neurotoxicity.

 

I have been to a doctor who actually told me that he injects himself with 10mg zinc intravenous every few weeks!!!

When I heard that I directly wondered if this is really healthy. That's a huge load of zinc at once. I wonder if that's not bad for the brain.

Edited by tfor, 29 June 2014 - 10:59 PM.

[arvcondor]

I'd like to see the article, but I highly doubt it.

[FW900]

I would not doubt that it is neurotoxic, there is significant evidence that excessive zinc in certain scenarios can cause neurotoxicity.

 

There are many variables, zinc can be neuroprotective in certain instances (likely through NMDAr antagonism) and neurotoxic in others (e.g., large amounts following a stroke). Unless you are taking zinc in massive amounts, it probably is nothing to be concerned about.

 

 

The Molecular Mechanisms of Zinc Neurotoxicity and the Pathogenesis of Vascular Type Senile Dementia

Zinc (Zn) is an essential trace element that is abundantly present in the brain. Despite its importance in normal brain functions, excess Zn is neurotoxic and causes neurodegeneration following transient global ischemia and plays a crucial role in the pathogenesis of vascular-type dementia (VD). We have investigated the molecular mechanisms of Zn-induced neurotoxicity using immortalized hypothalamic neurons (GT1–7 cells) and found that carnosine (β-alanyl histidine) and histidine (His) inhibited Zn2+-induced neuronal death. A DNA microarray analysis revealed that the expression of several genes, including metal-related genes (metallothionein and Zn transporter 1), endoplasmic reticulum (ER)-stress related genes (GADD34, GADD45, and p8), and the calcium (Ca)-related gene Arc (activity-related cytoskeleton protein), were affected after Zn exposure. The co-existence of carnosine or His inhibited the expression of GADD34, p8, and Arc, although they did not influence the expression of the metal-related genes. Therefore, ER-stress and the disruption of Ca homeostasis may underlie the mechanisms of Zn-induced neurotoxicity, and carnosine might be a possible drug candidate for the treatment of VD.

→ source (external link)

 

Neurotoxicity of Zinc in Vivo

[Poorly translated] The elegant paper on zinc effects in neuronal cultures (1) clarifies the entry of its ions by a specific channel in the cells. The results are, however, difficult to evaluate in view of limited neurotoxicity of zinc salts in adult animals. In our study on adult rabbits, the animals did not display obvious neurotoxicity in a peroral exposure through drinking water up to 4 weeks (2).

Specifically, the motor conduction velocity in sciatic nerve did not decrease while a concomitant exposure to lead acetate caused a decrease (2). At the same time, the blood zinc concentration increased very significantly while that in brain or in sciatic nerve was less marked. This could be caused by the induction of the metallothionein, its carrier, by zinc (3) and by the efficiency of the blood brain and blood nerve barriers in preventing its entry in the nervous system.

→ source (external link)

 

Zinc neurotoxicity to hippocampal neurons in vitro induces ubiquitin conjugation that requires p38 activation

There is increasing evidence showing that zinc plays a key role in inducing neuronal death during central nervous system injury. However, the underlying mechanisms are poorly understood. Here we assessed the effect of zinc on ubiquitin conjugation and subsequent neurodegeneration using cultured hippocampal cells. We report that cultured neurons are vulnerable to increased level of extracellular Zn2 +. Zn2 +-induced poly-ubiquitination in cultured neurons is in a concentration- and time-dependent manner. Furthermore our data demonstrated that Zn2 +-induced ubiquitination requires p38 activation. These findings indicate that excessive zinc could impair the protein degradation pathway and may be a crucial factor mediating neuronal death following traumatic brain injury.

→ source (external link)

 

Zinc in traumatic brain injury: from neuroprotection to neurotoxicity.

PURPOSE OF REVIEW:

In light of the recent recognition that even mild forms of traumatic brain injury (TBI) can lead to long-term cognitive and behavioral deficits, this review examines recent data on the neuroprotective and neurotoxic roles of zinc after brain injury.
RECENT FINDINGS:

Data show that treatment using dietary and parenteral zinc supplementation can reduce TBI-associated depression and improve cognitive function, specifically spatial learning and memory. However, excessive release of free zinc, particularly in the hippocampus associated with acute injury, can lead to increases in protein ubiquitination and neuronal death.
SUMMARY:

This work shows the need for future research to clarify the potentially contradictory roles of zinc in the hippocampus and define the clinical use of zinc as a treatment following brain injury in humans. This is particularly important given the finding that zinc may reduce TBI-associated depression, a common and difficult outcome to treat in all forms of TBI.

→ source (external link)

[Ames]

I know that this isn't scientific, but zinc leaves such an awful (albeit fleeting) taste in my mouth and in the back of my throat that it seems as if my brain is rejecting it. It's almost like I can feel the taste in my brain, if that makes sense. Nothing else is quite as deeply repellent as zinc for me. Based on this reaction alone, zinc instinctually seems to be toxic to me and I therefore mostly avoid it. I know this perception is irrational, yet my physical response is hard to ignore as far as my willingness to take the mineral is concerned. I find it peculiar that I don't come close to feeling this way about anything else save for, perhaps, the Tongkat Ali that I have that I swear tastes metallic (perhaps due to potentially high lead content). Needless to say, I don't take that either.

Edited by golgi1, 30 June 2014 - 05:29 AM.

[medicineman]

Zinc and copper are what amyloid plaques are (mostly) comprised of. I don't know how relevant that is to zinc neurotoxicity but I personally would steer away from any metal over rda.

http://www.ncbi.nlm....ubmed/11430801/

This is just one of many papers out there.

[scitris]

zinc is well known for his cytotoxic abilities above a certain concentration. But its also a very important molcecule that acts as a cofactor in many enzymatic reactions in neurons. So its all about not taking to much. 10mg injections every few weeks isnt too much. 

[tfor]

And how much daily oral zinc is too much? I only know that more than 50mg interfere with copper.

 

Do we know how much zinc a person should take daily and when exactly it starts to become neurotoxic? Does this depend on blood levels?

My zinc levels are rather low.

[eon]

wouldn't taking a copper sourced food like nuts counter zinc's effects on copper? I could think of macadamia as being high in copper. This is expensive though. I think macadamias has some cyanide chemicals too so don't take too much. It's toxic to dogs from what I've read, not sure what it does to humans but I felt weird when I ate about 5 pieces of it. Maybe I should eat only 1 piece.

Edited by eon, 26 December 2014 - 01:54 PM.

[Joe Monroe]

neurotoxic? I don't think so, what is this article you speak of? I was reading this post about the disease, I do believe there is some validity to it. There aren't a ton of really elaborate studies done on it though but... I mean most supplements and vitamins don't have those either so what would one expect. 

 

oops sorry that was the wrong link... lol. 

 

But.. 

 

First, do pyrroles exist? Yes. "A pyrrole is a heterocyclic aromatic organic compound..." (wiki) 

Taking a cue from that definition, I searched heterocyclic amines. That gave me a little more info, 
"Pyrrole is another compound made up of molecules with a five-membered heterocyclic ring. These molecules are unsaturated and contain a nitrogen atom in the ring. Four pyrrole rings are joined in a ring structure called a porphyrin."(wiki) 

Searching porphyrin disorders yielded an article on the National Digestive Diseases Information Clearinghouse on the NIH.gov site: 

http://www.niddk.nih...acts.aspx#types

and this one: 

http://www.ncbi.nlm....pubmed/22335011

A pilot study done by ACNEM scientists in New Zealand on the 
Parliament of Australia website by the title of "The Effectiveness of Targeted Nutrient Therapy in Treatment of Mental Illness" presents reinforcing information as well. 

Edited by Joe Monroe, 27 December 2014 - 10:11 AM.

[eon]

Sounds like you're taking too much zinc, Joe! Look at you! All over the place! 

[Jeff McJackoff]

who cares man.

just eat it from the food. and be thankful for it.


why does it matter if its neurotoxic?, you need to eat it from food anyway. just eat it from food.

[Jeff McJackoff]

666 TOPIC VIEWS!!!!