it's hypercalcemia that kills the rats when they ingest d3.Liberation wrote:Researchers do use mice and rats when they are examining relations between MS and D3 defficiency. So, I think it should be more carefully examined in this case as most of us are taking D3 suppliments. There are also too many scarring issues that we hear about.
hypercalcemia is not good for people either and thus the historical hoopla about d3 toxicity in humans.
yes, serum d3 levels of 250 nmol/L and higher put humans at risk for hypercalcemia. no, ms patients should not be aiming for serum d3 levels above 250 nmol/L.
according to research, ms patients should ensure levels are up over 100 nmol/L.
have i personally tested with serum d3 over 250 nmol/L? yes, accidentally. i megadosed 50,000 IU per day for 8 days expecting my level to go from 103 to 150 nmol/L, consistent with previous dose-response. instead, on follow-up testing i went to 271 nmol/L.
what was different? i had identified and corrected a zinc deficiency in the meantime. i hypothesize that the liver requires zinc to complete the hydroxylation process which converts ingested cholecalciferol to 25(OH)hydroxycholecalciferol. i can't find a specific study to back that up, but i can find breadcrumb studies:
Impaired hepatic 25-hydroxylation of vitamin D is also seen in patients with alcoholic cirrhosis...
(Mawer EB et al. (1985) Metabolism of vitamin D in patients with primary biliary cirrhosis and alcoholic liver disease. Clin Sci 69: 561-570)
Zinc deficiency commonly occurs in patients with cirrhosis and has been implicated in the pathogenesis of hepatic encephalopathy...
(Gruengreiff K et al. (2000) Zinc deficiency and hepatic encephalopathy. J Trace Elem Exp Med 13: 21-31)
i'm procrastinating right now, so not going to keep digging for the study where supplementation with zinc reverses liver cirrhosis. makes sense since alcohol depletes zinc, and tight junctions are altered in cirrhosis... remember how zinc regulates tight junction permeability? that has been discussed previously in the context of intestinal permeability/leaky gut. anyway all those points should already have study links posted somewhere here at TIMS.
the take away point is, test your levels and you'll be good. and be nice to your liver