Unexplained neuropathy? Make sure you are tested for B6 toxicity. If you are supplementing, the blood levels drop quickly when they are stopped so to prove toxicity, get lab work while on supplements. Something to consider in your quest for health. It happened to me. I was on supplement wayyyyy lower than the USA upper limit and took doctors many months to figure it out.

I'm in the process of trying to figure out if I'm especially sensitive to B6, as it may have exacerbated my PN. Be sure to check other supplements for B6 content. I thought I was only getting the 25 mg that was in my B complex (which actually helped me regrow hair that had thinned badly), but when I looked at other labels it turned out I was taking 50 mg. total.

It is known that excessive consumption of pyridoxine/Vitamin B6, regardless of whether it comes from food or supplement sources, can lead to sensory neuropathy.

The Recommended Dietary Allowance for it is 1-2 mg/day and the Tolerable Upper Intake Level (UL) is 100 mg/day for adults. If you are eating supplements which are rich in Vitamin B6 you could be over the UL.

There is more information about this here; http://lpi.oregonstate.edu/mic/vitamins/vitamin-B6.

Last February, about six months ago, I starting have strange symptoms. Zapping in my toes, pain in my fingers, and a sore tongue. I googled and I'm sure you can all relate to this. I saw B6 toxicity all over the web. It perfectly matched my symptoms. I quickly took a look at my supplements. The b-complex I'd just started had 50mg of B6. I immediately stopped it, and then basically bought the other b-vitamins all separately so I could control what I was taking.

Over the next few weeks, the zapping didn't go away, but it didn't get any worse. My tongue did feel better. A few months went by, and I started having new symptoms, hormonal changes, problems sleeping and depression. And then, my sore tongue came back. This time, I started doubting the B6 toxicity thing. B6 deficiency has the exact same neuropathy symptoms as B6 toxicity. I decided to take 25mg of B6 for a few days and see what happened.

Well, here's what happened. I felt much happier. It was almost immediate. My period issues improved. BUT...my neuropathy got worse. So then I read about Alpha Lipoic Acid, which is a treatment for B6 toxicity and diabetic neuropathy. The ALA helped at first, but then it seemed to make me feel awful... fatigue, irritability and heart palpitations.

Long story short, I finally found something saying ALA can deplete thiamine in people who are low. Thiamine deficiency accounted for ALL of my symptoms, including neuropathy!!! And then I kept reading. B6 supplementation can increase the requirements for thiamine. Once I stopped the ALA, and really really upped my thiamine supplementation, my neuropathy went away completely! So has the sore tongue.

So now I don't believe any of my symptoms were B6 toxicity. The sore tongue, the zapping in my toes, the finger pain, all of this was deficiency of probably both B6 and thiamine.

Many things deplete thiamine, it turns out. I'll give you the quick list here: tea, coffee (even decaf), raw fish, ALA, alcohol, and illnesses involving diarrhea. Some intestinal bacterias can steal thiamine and you'd never even know it. Thiamine requires a lot of acid to be absorbed so if you take acid reducers, or if you have a thyroid issue you can be deficient in thiamine.

I never had my blood levels of B6 tested, and this is because I have read all the studies and I don't think we ever really proved that high blood levels of P5P are indicative of toxicity. Serum levels are a very poor indicator of what's happening inside cells, where it really matters. We don't really know what high P5P in blood means. High P5P in blood could mean that B6 isn't being taken up by the cells. A deficiency state could still exist even with high blood levels of B6. I think it's dangerous to assume too much information from serum blood tests of vitamins.

I eventually worked up to taking almost 300mg of B6 a day, along with very high doses of thiamine and other b-vitamins. And after two months of this, a miracle happened. I had three breast lumps for the past four years in my right breast. I've had four mammograms and a biopsy (fibroadenoma). I was told I'd likely need to be biopsied and checked every six months. Well, one night, during the second month of the high dose of B6, my right breast suddenly got a giant swollen lump, right where my biopsied lump was. I freaked out of course. But in three days, it went away, and so did my lump! Now I have ZERO lumps!!! It's really amazing. I can't shut up about it. I guess I didn't know how stressed out I was about having these breast lumps. Later, I read that women with the highest levels of P5P in serum have been found to have the lowest incidence of breast cancer. (Note that I also take iodine as a supplement, and B6 and iodine work together.)

Derrick Lonsdale is a nutritionist who has written a lot of articles, many about thiamine. He's an amazing researcher. I highly recommend searching him, and reading up on thiamine.

Best,
Amy

Where did you see that b6 depletes thiamine? I know b1 can deplete b6, but where did you see that? I find this post intriguing and want to talk to you.