17 replies to this topic

[Kutta]

Greetings!

As you see this is my very first post here, and I can say for sure that I'm also some sort of newb compared to those people who dedicated decades to life extension, I only started this whole thing about two years ago.

I've read several times about pyridoxine's neurotoxic side effects.

For example medicineman posted recently on this thread: http://www.imminst.o...showtopic=25465

"1) Seven adults developed progressive sensory ataxia and profound limb impairment of
position and vibration sense after consumption of large daily doses of pyridoxine (2 to 6
g) for 4 -40 months (3).
(2) Daily doses as low as 500 mg of vitamin B6 may result in neuropathy (5).
(3) Sensory neuropathy from low-dose pyridoxine occurred in individuals ingesting 0.1 to
4.0 g for 6 years (2).
(4) Photosensitive lesions, vomiting, and peripheral neuropathy developed in children
with Down's syndrome being treated with high doses of pyridoxine (1).
(5) 103 women demonstrated impaired neurological function while attending a private
clinic and ingesting an average of 117 + 92 mg of pyridoxine for a period ranging from 6
months to 5 years (3).
(6) Acute sensory neuropathy-neuronopathy from pyridoxine developed in an individual
ingesting 61 g for 3 days (2).
(7) Excessive amounts of pyridoxine appear to cause degeneration of dorsal root ganglia
(4).
(8) Daily digestion of a high dose B-vitamin was associated with an acneiform eruption
that promptly improved after discontinuation of the vitamin (6).
(9) A woman exposed for 13 years to high daily doses of vitamin B6 (up to 10 g)
developed sensory neuropathy with a slight motor component (2)."


I'm taking currently a B-100 complex (Scitec). I mostly trust LEF and I know they've got 100mg pyridoxine in their mix. However medicineman wrote (3) that "from 0.1g" dose sensory neuropathy did occur. Others say that it's safe under 200mg per day.

I'd like to ensure that 100mg pyridoxine won't damage me even when taken for a very long time. What do you know about this?

[edward]

Thats kind of alarming I personally don't know what to make of it.

[Forever21]

Didn't you hear? Its hard to miss. NEWS are all over the recent reports on supplements. They don't work and may harm you.

http://www.imminst.o...o...c=25370&hl=

Edited by Forever21, 17 November 2008 - 03:11 AM.

[ajnast4r]

its well known that the tolerable upper limit for pyridoxine is 100mg, and doses above than can cause neuropathy and nerve damage. you should not be consuming more than 100mg per day from all sources... i would say you probably shouldnt consume more than 200-300% DRI, atleast that's what we're taught in school. i would suggest you read through this site and familiarize yourself with the DRI's and TOL's for everything youre taking... and dont forget to include food sources (track your eating in cron-o-meter for a week to get your averages)

[niner]

Yeah, 100mg. This is well known, as ajnast said. So much so that when I went to a neurologist with some mild neuropathy symptoms, that was one of the first things he asked about. I was already sufficiently on top of it that I had stopped my daily pyridoxamine. For some reason, I was getting 20mg of pyridoxine in my ALCAR from some major manufacturer that I've since forgotten. My understanding is that most people can get away with somewhat more than 100mg, but problems have shown up at levels as low as that or even lower. It's not that hard to get extra amounts of it from other supplements where you aren't expecting it, your multi, or food.

[edward]

Interesting that 200 mg sustained release tablets are sold at your local drugstore/grocery store.

I probably wrote off (due to water solubility) the B6 dosage issue in my mind when I first learned about "vitamins" and never gave it another thought.

I tend to overlook the basic vitamins when researching supplements and the like.

Edited by edward, 17 November 2008 - 09:13 PM.

[FunkOdyssey]

While you want to avoid any significant quanitity of pyridoxine, don't write off B6 entirely, because neurotoxicity seems to be unique to that particular form of B6. Sources of B6 that are safe at high doses include P5P (this form is found in AOR Ortho-Core) and Pyridoxamine, the AGE-preventing wonder vitamin.

[kismet]

So if the neuro-toxicity is real and not just a rare side-effect and generally present, should we not take pyridoxine at all?

Do you know if pyridoxamine and P5P also increase dream-salience (vivid dreams)? I'm frequently taking 200mg b6 for several weeks and then again pausing for some time. I've always thought neuropathies are due to long term use and neurpathies never ocurred below 200mg. Maybe I should adjust my intake...
On the other hand neurotoxicity does not seem to be obligatory, even at doses between 200-500mg. Or maybe it just doesn't reach a significant threshold.

Edit:
How likely is it that some neurotoxic effect is responsible for the increased dream-salience?

Edited by kismet, 17 November 2008 - 10:05 PM.

[FunkOdyssey]

So if the neuro-toxicity is real and not just a rare side-effect and generally present, should we not take pyridoxine at all?

Pyridoxine causing neurotoxicity is real but seems to be dose dependent. Why chance it when better alternatives exist?

[kismet]

So if the neuro-toxicity is real and not just a rare side-effect and generally present, should we not take pyridoxine at all?

Pyridoxine causing neurotoxicity is real but seems to be dose dependent. Why chance it when better alternatives exist?

Yeah, I've read it may have to do with unmetabolised pyridoxine, so it would depend on your liver's ability to metabolise it. Say hello to incredible variability :-/
Well, I want the increased occurrence of vivid dreams that I get with b6, so I'm wondering if this also applies to p5p and pyridoxamine...

[4eva]

Actually dream recall is a good indication of your B6 levels. Little or no dream recall would mean you are deficient. If 100 mg of B6 gives you good dream recall (dream recall 3 or 4 days a week) then you don't need to take any more than that.

But the p-5-p form is also good to take. Your liver can have problems over time converting pyridoxine into the active form.

If you take high doses of B6 without adequate magnesium you might expreience more symptoms of toxicity.

I've experienced the toxicity; I had pain from an excited nerve ending. It goes away if you stop taking B6 (all forms) and avoid a lot of foods. B6 is found in many foods (including junk foods).

I've read that 250 mg should be the cutout dose to avoid toxicity. But symptoms of tingling in the hands and feet could be a sign of inadequate magnesium levels.

[ajnast4r]

Actually dream recall is a good indication of your B6 levels. Little or no dream recall would mean you are deficient.

that is absolutely not true

[4eva]

http://lib.bioinfo.pl/pmid:11883552

[FunkOdyssey]

I think what ajnast4r meant was that, although B6 is an important factor in dream recall, an absence of dreaming or dream recall does not automatically mean you are deficient in B6. There could be many other reasons.

[ajnast4r]

I think what ajnast4r meant was that, although B6 is an important factor in dream recall, an absence of dreaming or dream recall does not automatically mean you are deficient in B6. There could be many other reasons.

thats exactly what i meant. lack of dream recall is not a sign of b6 deficiency.

Edited by ajnast4r, 19 November 2008 - 12:32 AM.

[neogenic]

I've read research that states p5p is not toxic at all. Not at all. The reason pyridoxine is toxic is it actually competes with endogenous p5p at higher doses and a deficiency of p5p is created. What's baffling is how many "P5P" supplements include a mix of the two.

Here's a Thorne monograph that goes in to the details: http://www.thorne.co...s_monograph.pdf

This is from an Alternative Medicine review:
http://findarticles....i_71948217/pg_2
Safety, Toxicity, and Side Effects

The use of supplemental P5P has not been associated with toxicity, although the inactive form, pyridoxine, has been associated with reports of peripheral neuropathy.[45] One hypothesis is that pyridoxine toxicity is caused by exceeding the liver's ability to phosphorylate pyridoxine to P5P, yielding high serum levels of pyridoxine which may be directly neurotoxic or may compete with P5P for binding sites, resulting in a relative deficiency.[46]

Mpofu et al reported electrophysiological and neurological examination of 17 homocystinuric patients who had been treated with 200-500 mg pyridoxine HC1 daily for 10-24 years, and found no evidence of neuropathy.[47] Most reported cases of neuropathy associated with pyridoxine supplementation have involved intake of at least 500mg/day for two years or more.[48] While there is no doubt that vitamin B6 can be neurotoxic in gross excess, there is considerable controversy over the way in which toxicological data have been translated into advised limits.[8]

[neogenic]

So if the neuro-toxicity is real and not just a rare side-effect and generally present, should we not take pyridoxine at all?

Pyridoxine causing neurotoxicity is real but seems to be dose dependent. Why chance it when better alternatives exist?

Clearly the better alternative, as in every case with the B-vitamins, is the co-enzymated form. P5P.

[neogenic]

Bump.