to my mind, zinc (and other) 'normal' ranges are massively and ultimately unethically deceptive
case in point. here is a selection of zinc reference or normal ranges
Zinc, Serum
https://www.mayomedicallaboratories.com ... etive/8620
Normal serum zinc is 0.66 to 1.10 mcg/mL......................................(aka 66-110 μg/dl)
Pediatric reference intervals for serum copper and zinc
Based on the central 95% ... the resulting reference interval determined for serum zinc was
................................................................................................64-124 μg/dl
(central 95% of course referring to the bell curve, so we are not seeing absolute highest and lowest values obtained)
local labs i've encountered here and elsewhere:
..................................................................11.5-18.5 μmol/L.......(75 - 121 μg/dl)
...............................................................10-20 μmol/L...............(65 - 131 μg/dl)
in research:
Determination of Serum Zinc Concentrations in Normal Adult Subjects ...
https://academic.oup.com/ajcp/article/57/4/506/1770331
'healthy young men'............................................serum mean 102, range 68-136 ug/dl
interesting contrasts:
Reference range of zinc in adult population (20-29 years) of Lahore, Pakistan
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4048503/
healthy individuals:..............serum mean 24, range 11.5-36.7 µmol/L (157, 75 - 240 μg/dl)
males:..............................serum mean 22, range 11.9-32.4 µmol/L (144, 78 - 212 μg/dl)
females:.............................serum mean 22, range 9.9-36.9 µmol/L (144, 65 - 241 μg/dl)
Reference values for serum zinc concentration and prevalence of zinc deficiency in adult Iranian subjects.
https://www.ncbi.nlm.nih.gov/pubmed/22592845
men...........................................................9.6 - 31.6 μmol/L........(63 - 207 μg/dl)
women.......................................................8.9 - 29.9 μmol/L.........(58 - 195 μg/dl)
total population...........................................9.3 - 30.8 μmol/L..........(61 - 201 μg/dl)
(and recall, based on that central 95% idea, we are not seeing the very highest or lowest levels identified in these groups)
Serum Zinc and Copper Status in Hospitalized vs. Healthy Elderly Subjects
http://www.tandfonline.com/doi/abs/10.1 ... 7.10719643
(you can download a pdf via researchgate)
this study's cutoff to establish low zinc status................ 0.70 mg/L (aka <70 μg/dl)
next, serum mean zinc levels in study subjects:
healthy elderly controls...........................................1.10 mg/L (aka 110 μg/dl);..........0% below 70 μg/dl
hospitalized group...................................................0.87 mg/L (aka 87 μg/dl);...............only 20% below 70 μg/dl
(clearly this cutoff leaves something to be desired)
nervous system disease ............................................94 μg/dl; 6% below 70 μg/dl
mental disturbance .................................................90 μg/dl; 13% below 70 μg/dl
cancers .................................................................89 μg/dl; 26% below 70 μg/dl
undefined symptoms .................................................88 μg/dl; 15% below 70 μg/dl
digestive diseases ....................................................88 μg/dl; 19% below 70 μg/dl
osteo-muscular disease ..............................................87 μg/dl; 14% below 70 μg/dl
endocrine/metabolic disease .......................................87 μg/dl; 19% below 70 μg/dl
infectious disease ...................................................87 μg/dl; 21% below 70 μg/dl
blood disease ..........................................................87 μg/dl; 24% below 70 μg/dl
cardiovascular disease ..............................................86 μg/dl; 19% below 70 μg/dl
genitourinary disease.................................................84 μg/dl; 21% below 70 μg/dl
trauma..................................................................81 μg/dl; 27% below 70 μg/dl
respiratory disease....................................................80 μg/dl; 36% below 70 μg/dl
takeaway points:
every single mean serum zinc level shown above, whether for healthy controls or across the entire spectrum of diseased and hospitalized patients, is technically 'normal'. *not*. *one*. serum mean zinc level reported for any patient/hospitalized subject comes in below the bottom of the listed reference ranges. that means no red flag if you request serum zinc test at the neighbourhood lab. you *must know* going in, the implications of results found inside the reference range.
70 μg/dl is not a beneficial cutoff to use when evaluating low or normal serum zinc in health vs disease
yes, when i gun for serum zinc ~ 120 μg/dl it can sound high, but it's well within 9 out of the 10 ranges shown above, and distinctly *outside* the patient ballpark. in some groups studied above, 'normal' serum zinc can exceed 200 μg/dl!
so to answer my own original question, what i am taking away from this personally, is that i'll accept a naturally healthy aging serum zinc decline to the ~ 110 μg/dl neighbourhood, but no lower.
question: where do *you* fit in?
