Zinc : Serum vs RBC

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Epsilon?
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Zinc : Serum vs RBC

Post by Epsilon? »

Sorry if this has been discussed. I searched.

RBC zinc testing is much more expensive. I got the idea that it was better but I can't recall the source. Anyway this is from the Mayo Clinic:
Since there is no demonstrable benefit to the red blood cell testing, Mayo Medical Laboratories strongly recommends that nutritional assessment be accomplished using the serum magnesium (MGS / Magnesium, Serum) and serum zinc (ZNS / Zinc, Serum) tests.
https://news.mayomedicallaboratories.co ... spotlight/

Is there general agreement that serum testing is ok?
rianlees
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Re: Zinc : Serum vs RBC

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Hi Epsilon,

My understanding is that serum or RBC are both acceptable when assessing zinc though will be more accurate when measured in a fasting state. As for magnesium, being an intracellular nutrient serum testing isn't very reliable.
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Re: Zinc : Serum vs RBC

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I would like to learn more about that. Do you have a source of information?
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Re: Zinc : Serum vs RBC

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So the NIH doesn't think serum or plasma zinc levels correlate with tissue levels but the report also doesn't give me much confidence in the value of testing. Zinc supplements may be beneficial for age related macular degeneration but they just supplemented w/o testing from what I can tell from the paper.

https://ods.od.nih.gov/factsheets/Zinc- ... onal/#en72
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Re: Zinc : Serum vs RBC

Post by rianlees »

HI Epsilon,

I got that from a Australian nutritionist named Rachel Arthur- a webinar I attended. I can go through my resources from the lecture when I am next at work (on my work computer) to find the references if you like?
Another thing about zinc levels...you haven't mentioned why you are testing...it is also useful to know zinc:copper ratio- as they antagonise each other, for instance zinc levels could look okay though you could have a 'relative' deficiency if copper levels are higher. The ideal ration is 1:1
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SusanJ
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Re: Zinc : Serum vs RBC

Post by SusanJ »

Epsilon? wrote:Zinc supplements may be beneficial for age related macular degeneration but they just supplemented w/o testing from what I can tell from the paper.
Actually, zinc was tested as part of the vitamin/mineral formula used for the Age-Related Eye Disease Study (AREDS) studies.

https://nei.nih.gov/areds2/MediaQandA
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Re: Zinc : Serum vs RBC

Post by Epsilon? »

Hi Susan, do you have a link specifically about the testing zinc levels? Your link doesn't mention it. The AREDS report 1 doesn't mention it. I haven't read all of the reports.

rianlees, I am interested in zinc copper ratios. If you have a reference on testingI would be interested. If it turns out that it is more opinion based, that's fine too.
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Re: Zinc : Serum vs RBC

Post by SusanJ »

Sorry, misunderstood your post.

If you look at most studies looking at zinc (in aging, in inflammation) they use either serum or plasma levels. Admittedly not perfect.
The parameter of choice is often serum or plasma zinc. However, this is not an ideal parameter for determining the zinc status. When zinc deficiency was experimentally induced in young subjects, they showed significant effects on the production of IFN-γ, IL-2, and TNF-α with an imbalance in the TH1/TH2 system, but plasma zinc was not significantly affected [47]. Whereas reduced plasma or serum zinc levels can indicate zinc deficiency, such deficiency can also occur at levels that are within the reference values [98]. Possibly, other parameters, such as labile intracellular zinc in leukocytes, will be a more accurate measure for the zinc status in the future [99].
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2702361/
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