Posted by Larry Hoover on August 27, 2007, at 13:37:01
In reply to Calling LAr Re. B6 and Zinc........., posted by teejay on August 27, 2007, at 7:52:16
> Hiya Lar,
Hey tj.
> Been reading the thread on pyroluria with interest as I too take B6 and zinc (albeit not as regularly as I'd like) and on the whole feel it helps me.
>
> I have noticed however that some peoples intake of B6 and Zinc are a little high. Can you offer comment on what you feel are safe upper dosages for these (even for a brief test regimen) and what negatives I should be on the look out for?Well, it's not clear cut, in the case of pyroluria, as there is an apparent excessive loss of these nutrients. Treatment might then invoke intake levels which are not consistent with those for individuals not losing essential nutrients in this way. That said, I have no quantitative information to go on, with respect to urinary losses. Nor do I have any typical physiological measures of chronic insufficiency to consider (zinc or B6 status). So, there's a fudge factor, but it's not known how large it is, nor whether it changes with time and/or treatment.
In general terms, a zinc supp should not get above 40 mgs/day, and assuming 10 mg from food, you're likely going to have some potential for modest suppression of copper uptake. That would be shown by a decrease in copper-dependent SOD (super-oxide dismutase) activity. Zinc supps can cause GI distress, but I'd call that sensitivity rather than toxicity. Some people just have to make sure they take zinc with food, is all.
In chronic zinc deficiency, levels substantially above that 40 mg ceiling might be warranted, but I'd not recommend that for more than perhaps 4 to 6 weeks duration, dropping back to 40 mg thereafter.
There is potential for immune suppression, but you'd not see anything overt, I wouldn't think.
With respect to pyridoxine, a reversible neuropathy characterized by paraesthesia is the typical adverse reaction from chronic overdose. The threshold for that is generally thought to be 800-1000 mg/day, and requires months of exposure......but there are case reports of neuropathy at much lower levels. It's interesting to consider the logic of how they set the UL (upper limit) for pyridoxine intake. One study showed no neuropathy or other adverse effects after long-term 100 mg/day, whereas another had a similar result after 300 mg/day. The took the *average*, i.e. 200 mg/day, then applied an arbitrary "safety factor" of 2 (other nutrients have safety factors of 1.5, or 4, or whatever), and set the UL at 100 mg/day.
Anyway, the thing to watch for is peripheral paraesthesia....numbness, tingling, shooting sensations. The symptoms should be completely reversible upon dose reduction. If they don't go away, it wasn't caused by the B6. The only case on record of irreversible neuropathy involved someone who persisted in taking 2 to 6 grams per day for two years, after developing symptoms of neuropathy.
> cheers mate, and hope this messages finds you feeling well! :-)
>
> TJI'm trying.
Hope you're well, too.
Lar
poster:Larry Hoover
thread:778999
URL: http://www.dr-bob.org/babble/alter/20070816/msgs/779079.html