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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 13 of 13. This is the beginning of the thread.
Posted by linkadge on December 2, 2004, at 19:16:37
I read an arcle that zinc could be neruotoxic if too much is taken. It said that zinc was responcable for neurotoxicity in certain situations. Do you know if this is true. Should high doses not be taken, or not at all ???
Linkadge
Posted by KaraS on December 2, 2004, at 19:34:50
In reply to Whats your take on Zinc Larry, Anyone ??, posted by linkadge on December 2, 2004, at 19:16:37
> I read an arcle that zinc could be neruotoxic if too much is taken. It said that zinc was responcable for neurotoxicity in certain situations. Do you know if this is true. Should high doses not be taken, or not at all ???
>
>
> LinkadgeI've never heard of too much zinc being neurotoxic but I have heard of it being counterproductive in terms of immune response. Might that ultimately lead to it causing neurotoxicity?
Posted by linkadge on December 2, 2004, at 19:57:07
In reply to Re: Whats your take on Zinc Larry, Anyone ?? » linkadge, posted by KaraS on December 2, 2004, at 19:34:50
What do you mean by counterproductive ?
I read an article that said that zinc had antidepressant properties. But then read another article saying it might be neurotoxic.
Confused
Linkadge
Posted by KaraS on December 2, 2004, at 21:26:44
In reply to Re: Whats your take on Zinc Larry, Anyone ??, posted by linkadge on December 2, 2004, at 19:57:07
> What do you mean by counterproductive ?
>
> I read an article that said that zinc had antidepressant properties. But then read another article saying it might be neurotoxic.
>
> Confused
>
> Linkadge
>
>
>Zinc is known to be good for stimulating/enhancing the immune system up to about 50 mg./day. When you start taking more than that, you're hindering rather than helping your immune system. I would have to do some research as to why that is to be able to see if that might translate into any neurotoxicity issues. Hopefully, Larry, Ray or Jan could speak more to this and then I wouldn't have to do the work. :-)
K
Posted by Mistermindmasta on December 4, 2004, at 14:02:53
In reply to Re: Whats your take on Zinc Larry, Anyone ??, posted by linkadge on December 2, 2004, at 19:57:07
> What do you mean by counterproductive ?
>
> I read an article that said that zinc had antidepressant properties. But then read another article saying it might be neurotoxic.
>
> Confused
>
> Linkadge
>
Here's the only possibility I can think of: the antidepressant properties of zinc are supposed to come from it's NMDA antagonist properties, similar to Riluzole or DXM. However, there is a phenomonem where too much NMDA antagonism can cause neurotoxicity. I can't remember how this works, exactly, but I'm thinking its along the lines of this: NMDA antagonism can raise levels of other neurotransmitters like dopamine, and I think when the levels of these other transmitters get too high, it can cause neurotoxicity. Thus, zinc could theoretically indirectly cause neurotoxicity.DXM is an antidepressant in low doses to due its NMDA antagonist properties, but in high doses it can cause neurotoxicity. I honestly don't think that zinc could ever antagonize the NMDA receptor as much as DXM, but maybe in theory it could. I just don't believe that you could ever get to such a point.
This is all just hypthesizing based on my little knowledge of the subject. I'm sure there are other possibilities of zinc induced neurotoxicity.
Posted by KaraS on December 4, 2004, at 16:00:13
In reply to Re: Whats your take on Zinc Larry, Anyone ??, posted by Mistermindmasta on December 4, 2004, at 14:02:53
It's very long so here are a couple of paragraphs first. Then I'll give you the link if you want to read more.
"Extracellular zinc may gain access to intracellular compartments through NMDA receptors [100], calcium-permeable AMPA receptors [101], or voltage-gated calcium channels [102]. After entering the cell, zinc can trigger widespread disruptions of normal cellular functions. Zinc has been proposed to disrupt calcium homeostasis [102], inhibit mitochondrial electron transport [52], disrupt tubulin assembly [103], and overactivate calcium-mediated enzymes [104]. Furthermore, zinc reacts with the thiol and imidazole moieties of many proteins, and, thus, can disrupt their structure and function [105]."
"Toxic effects of zinc on hippocampal and cortical neurons also have been observed in models of Alzheimer's disease. Recent in vitro studies have shown that zinc induces beta-amyloid (betaA) protein clumping similar to that found in the senile plaques associated with Alzheimer's disease [73-77]. This aggregated (clumped) form of betaA protein has been found to be cytotoxic to hippocampal and cortical neurons, and it has induced apoptic cell death in in vitro studies [78]. betaA protein also has been shown to enhance the susceptibility of cultured human and murine cortical neurons to excitotoxic injury [79, 80]. Bush and colleagues have reported that low (i.e., physiological) concentrations of zinc (e.g., <5 µM) can aggregate betaA [73, 74]."
http://www.protein.bio.msu.ru/biokhimiya/contents/v65/full/65070949.htm
Posted by linkadge on December 5, 2004, at 11:20:46
In reply to Re: Good article on this, posted by KaraS on December 4, 2004, at 16:00:13
It sounds pretty scary. I don't know if I want to supplement with zinc after reading this.
Linkadge
Posted by KaraS on December 5, 2004, at 15:04:50
In reply to thats the article I'm reffering to, posted by linkadge on December 5, 2004, at 11:20:46
Posted by Larry Hoover on December 10, 2004, at 11:35:36
In reply to Whats your take on Zinc Larry, Anyone ??, posted by linkadge on December 2, 2004, at 19:16:37
> I read an arcle that zinc could be neruotoxic if too much is taken. It said that zinc was responcable for neurotoxicity in certain situations. Do you know if this is true. Should high doses not be taken, or not at all ???
>
>
> LinkadgeThe article references free zinc, i.e. water-soluble Zn++ ions. Your body is perfectly capable of managing zinc from oral intake, because zinc only enters the body via very specific zinc transporters (four types identified so far), and once across the gut wall, there the zinc is met by carrier proteins called metalothioneins. That makes the zinc ions bound. There is virtually zero free zinc ever, anywhere in the body, except under very gross disturbances of metabolic processes.
I do not have the slightest hesitation in recommending zinc supplements to anyone, especially depressives.
Lar
Posted by Larry Hoover on December 10, 2004, at 11:37:47
In reply to Re: Whats your take on Zinc Larry, Anyone ?? » linkadge, posted by KaraS on December 2, 2004, at 21:26:44
> > What do you mean by counterproductive ?
> >
> > I read an article that said that zinc had antidepressant properties. But then read another article saying it might be neurotoxic.
> >
> > Confused
> >
> > Linkadge
> >
> >
> >
>
> Zinc is known to be good for stimulating/enhancing the immune system up to about 50 mg./day. When you start taking more than that, you're hindering rather than helping your immune system. I would have to do some research as to why that is to be able to see if that might translate into any neurotoxicity issues. Hopefully, Larry, Ray or Jan could speak more to this and then I wouldn't have to do the work. :-)
>
> KToo much zinc intake inhibits copper uptake. You need a low but stable concentration of copper for normal immune functioning.
Zinc and copper also interact in one form of the enzyme superoxide dismutase. Free superoxide anion plays havoc with the immune sytem.
Lar
Posted by Larry Hoover on December 10, 2004, at 11:44:23
In reply to thats the article I'm reffering to, posted by linkadge on December 5, 2004, at 11:20:46
> It sounds pretty scary. I don't know if I want to supplement with zinc after reading this.
>
> LinkadgeThe issue is not the presence of zinc. The neurotoxic effect is caused by the absence of carnosine.
The various neuromodulators (zinc included) do not function in isolation. This article isolates one neuromodulator, and describes the effect if that one substance goes seriously outside regulatory control. That will not happen, in normal physiological states, or even most abnormal physiological states. Zinc is but one instrument in a symphony of neuromodulation.
Avoiding zinc would be like avoiding oxygen to prevent oxidative stress. If you succeed, you will have won a battle but lost the war.
Lar
Posted by linkadge on December 17, 2004, at 17:21:55
In reply to Re: Whats your take on Zinc Larry, Anyone ?? » KaraS, posted by Larry Hoover on December 10, 2004, at 11:37:47
Thanks for the advice, I'm too quick to toss supplements because of fear.
Linkadge
Posted by Larry Hoover on December 18, 2004, at 10:49:02
In reply to Re: Whats your take on Zinc Larry, Anyone ??, posted by linkadge on December 17, 2004, at 17:21:55
> Thanks for the advice, I'm too quick to toss supplements because of fear.
>
> LinkadgeI cannot believe the depth of the propaganda emanating for the United States about the adverse effects from vitamin supplements. One of the few two-time winners of the Nobel Prize, Linus Pauling, faced immense resistance from the medical establishment when he first proposed the intake of vitamin C at greater than the RDA.
If you have the time to read a moderate-length essay, you might be interested in the following:
http://www.internetwks.com/pauling/hoffer.html
Lar
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