Posted by Larry Hoover on November 6, 2002, at 11:19:36
In reply to Re: B vitamins » Alara, posted by bluedog on November 6, 2002, at 10:23:57
> Unless you are taking absolute mega doses,
> the B vitamins are essentially non-toxic.
> The B vitamin to be most careful of would be
> B6 which may cause nerve damage with
> sustained high doses as mentioned in an
> earlier post above by Larry Hoover( Larry is
> also right that a lot of reports on B6
> toxicity are anecdotal reports only though
> the consensus amongst vitamin experts seems
> to be that caution
> needs to be taken in doses above 500mg B6 per
> day though there have been isolated reports
> of problems occurring from lower doses of say
> above 100mg per day)I decided it would be worthwhile to post some abstracts.
Funct Neurol 1993 Nov-Dec;8(6):429-32
Sensory and motor neuropathy caused by excessive ingestion of vitamin B6: a case report.
Morra M, Philipszoon HD, D'Andrea G, Cananzi AR, L'Erario R, Milone FF.
Department of Neurology, San Bortolo Hospital U.L.SS. n. 8, Vicenza, Italy.
We describe a patient who developed a severe sensory and a mild motor neuropathy. This syndrome was due to massive and prolonged ingestion of vitamin B6 (10 g daily for 5 years). To our knowledge this is the first published case of motor neuropathy caused by chronic abuse of vitamin B6.
Neurology 1985 Oct;35(10):1466-8
Sensory neuropathy with low-dose pyridoxine.
Parry GJ, Bredesen DE.
We describe 16 patients with neuropathy associated with pyridoxine abuse. The clinical picture of a pure sensory central-peripheral distal axonopathy was consistent. Pyridoxine dose was 0.2 to 5 g/d, and duration of consumption before symptoms was inversely proportional to the daily intake. In all patients with adequate follow-up, improvement followed discontinuation of pyridoxine. The ready availability of up to 1-gram tablets makes it likely that this neuropathy will continue to be seen.
Acta Neurol Scand 1987 Jul;76(1):8-11
Characteristics of pyridoxine overdose neuropathy syndrome.
Dalton K, Dalton MJ.
A newly recognised neurotoxic syndrome due to pyridoxine (B6) overdose is described. It is the largest series of B6 intoxication hitherto reported. A raised serum B6 level was present in 172 women of whom 60% had neurological symptoms, which disappeared when B6 was withdrawn and reappeared in 4 cases when B6 was restarted. The mean dose of B6 in the 103 women with neurological symptoms was 117 +/- 92 mgs, compared with 116.2 +/- 66 mgs in the control group. There was a significant difference (P less than 0.01) in the average duration of ingestion of B6 in the neurotoxic group of 2.9 +/- 1.9 years compared with 1.6 +/- 2.1 years in controls. The symptoms were paraesthesia, hyperaesthesia, bone pains, muscle weakness, numbness and fasciculation, most marked on the extremities and predominantly bilateral unless there was a history of previous trauma to the limb. These women were taking a lower dose of B6 than previously described (1,2), which may account for the complete recovery within 6 months of stopping B6.
Note that there is a marked variability within groups (dose), but that neuropathy was significantly correlated with duration.
What stands out in these reports is that the neuropathy takes a significant period of time to manifest itself, and, a significant period of time to remit.
This is consistent with the behaviour of vitamin B12. Alone among the B vitamins, B12 is stored in the liver. B12 is essential for the formation of myelin, the electrical insulation for the nervous system. B6 neuropathy seems remarkable consistent with B12 deficiency (no mention of pernicous anemia in the case reports, but maybe they didn't look, or didn't see it as relevant).
This syndrome seems to emphasize the point that B-vitamins should never be individually supplemented at high doses.
> Anyway back to your question whether excess B vitamins puts extra stress on your kidneys. I think probably not at reasonable doses but then again if you keep filling your car tank after it's full the spillage may damage the paintwork.
I think it's dangerous to take analogies beyond their initial conditions. That said, having excess B-vitamins in the urine may contribute to urinary tract infections. Untreated, UTIs can affect the kidneys.
> These are my views on the subject
> keep wellMine are only conjecture, as well.
Lar
poster:Larry Hoover
thread:126299
URL: http://www.dr-bob.org/babble/20021101/msgs/126678.html