Pernicious Anaemia Society
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Does Nitrous Oxide Negate B12?

I was diagnosed with PA 12 years ago, but had the terrible fatigue and other symptoms for 10 years before that. I get B12 injections every two weeks, and that mostly works OK, although some symptoms will never go away.

Then two years ago I had another frightening downturn in health. I steadily lost my ability to keep my balance and to walk normally. After two months, I had to use a cane and moved very slowly. The fatigue was horrible, headaches were a constant, and I developed double vision. I could only lift my left leg to get out of a car by lifting it up with my hands and moving it out. I had trouble thinking clearly. This downward spiral continued for 9 months, and then, all at once it reversed, as quickly as it had arrived.

The only thing that had been different in my life 9 months before was a root canal with the use of novacaine and nitrous oxide. The root canal took 2.5 hours because of an emergency patient arriving. Two weeks after this root canal, I awoke with a splitting headache and double vision, and everything went downhill. My doctor ordered tests, there were two MRIs, a neuro consult, and neuro testing, but no cause was determined. Could all that Nitrous have depleted B12 to the point that it took months to catch back up?

Sorry to be so long winded. If you stuck with me...Thanks!

24 Replies

Hi lindajanes. Nitrous oxide oxidises B12 making it inactive, although it seems it may still show up on a serum B12 test:

Healthy people have 2 - 4 years supply of B12 stored their livers. An anaesthetist colleague told me that an 8 - 12 hour anaesthetic in which nitrous oxide is used can oxidise all that stored B12. I imagine if your stored B12 is low, 2.5 hours of nitrous oxide could easily inactivate it all. You would then need loading doses again to get you back to where you were before the nitrous insult. Your 2 weekly injections probably took a long time to replenish your B12 store. I will never let anyone use nitrous oxide on me, ever.


Thank you! This makes sense now....a ton of health issues that then disappeared months later was a mystery to my doctor, too, even though some tests of balance and coordination during and after convinced us both that our assessment was accurate. In the US, nitrous oxide is generally regarded as benign.. the dentist/patient friendly option. I appreciate the link, too. No more nitrous for me, either.

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Oh my! I left my career as a midwife in 2015. At the Trust where i worked the birth rooms had NO gas scavenging units nor were midwives provided with personal monitoring badges. Entonox is a heavy gas and sits like water in rooms. As midwives we spend a lot of time on the floor with women nearly all of those women woulsd huff on entonox for hours on end. Windows werent open unless it was hot weather. I believe this has cost me my career ...i am hypothyroid as well but despite normal thyroid blood levels now I remain as symptomatic as ever.


This article suggests scavenging should be used to protect staff when nitrous oxide is used, and has a few references:

My anaesthetist colleague (actually my boss when I was working as a biomedical engineer in an anaesthetic department in a big public hospital) also told me of a woman who successfully sued the hospital when she developed peripheral neuropathy after being given nitrous oxide repeatedly over several days for pain relief. It was he who alerted me to the possibility of B12 deficiency when the several neurologists I saw couldn't find a cause for my peripheral neuropathy.

The effect of nitrous oxide on B12 has been known for a long time so there is no excuse.


Hi lindajanes I guess it's "water under the bridge" (or down the canal?) now but another useful link is:

Nitrous oxide is a super-oxidiser when it comes to B12 and converts it to a form that the body cannot use, so if you had had an absorption problem and couldn't replace your the oxidised B12 with new B12 then it would have been a permanent problem.

I am not a medically trained person but I've had P.A. (a form of B12 deficiency) for more than 45 years.

I wish you well



Ha! Good pun. It's a relief to have an explanation and not wonder if another long downhill slide was in my future. I really appreciate the reply, clivealive. New question, if you feel like answering: As someone with decades of PA experience, have you noticed that your injections are somewhat less effective as you get older? I am in my early 70's, and it seems to be so, but it is hard to be sure it is just not aging in general.


To be honest I lived the first 40 years in complete ignorance of what P.A. was all about as during that time I didn't know anyone else with it and neither nurses who gave me my four weekly injections of cyanocobamalin B12 nor a succession of doctors I saw for other ailments ever asked me how I was coping.

I did however notice on occasion some neurological symptoms in the run up to my next injection so every few months or so I used to "slip in" the odd three week appointment.

One day 2011 I made the mistake of saying to my nurse "see you in three weeks" having already booked the appointment at reception and she said I won't do that as your prescription says "every four weeks" and she reported me to my G.P.

I was called in to see him and he categorically refused to change my prescription saying that my "pains" couldn't possibly be due to P.A. because I was having the injections.

I then joined the P.A. Society and asked the question on their then forum "Am I the only person in the world to experience a return of neuropathy in the run up to my next injection.....?" and I was absolutely amazed at the response. NO! I was not alone...

I learned all I could from the P.A.S website and went back to my "one size fits all" doctor taking my wife with me who could validate some of the physical manifestations such as pallor, unsteady gait, poor breathing, exhaustion, mood changes etc., which were more noticeable during the fourth week and after much persuasion my prescription now reads "as instructed" and I have the injections every three weeks.

As I'm not medically trained I cannot answer whether increased age renders B12 less effective. It is true that with people over 60 their stomach acid depletes which makes their take up of B12 from their food less efficient. However as so many on here also "feel the need" for more frequent injections I think it comes down to the individual.

My original doctor when she told me I had P.A. gave me two years to live - unless I ate raw liver three times a day or had B12 injections for the rest of my life. I chose the injections :) I was 30 then and I'm still "clivealive" at 76.



UK link about nitrous oxide and B12 deficiency

Link to b12 Deficiency Info website, mentions Nitrous Oxide

The effects of Nitrous Oxide on B12 are also mentioned in following two books...

"What You Need to Know About Pernicious Anaemia and B12 Deficiency" by Martyn Hooper

Martyn Hooper is the chair of PAS (Pernicious Anaemia Society). Book is up to date with UK b12 guidelines.

"Could it Be B12?: An Epidemic of Misdiagnoses" by Sally Pacholok and JJ. Stuart (USA authors)

Very comprehensive with lots of case studies.

Post from Martyn Hooper's blog about PA and B12 issues, mentions Nitrous Oxide

I am not medically trained.

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Thank you so much! I really appreciate the links to the original info sources, Sleepybunny. I can share them with my doc. Many thanks for the time it took to do this!


Thanks for links Sleepy Bunny. I was previously unaware. Such information is invaluable :)


If I was you I would google holistic dentistry. Because I had my amalgam/mercury fillings out re having an autoimmune disease so had to do a lot of research. And came across info re Root Canals and negative health outcomes and determined never to have one. I will post an expert interview. I have not listened to this so have no idea what the dental expert is saying. But I trust Dr Mercola's site. Dr Mercola walks what he talks so he has my respect.


What a shame that the FDA and the Better Business Bureau don't think too much of him.


Just trying to help here. It is not Mercola who is the Dental Expert - just his guest so what he has to say will be relevant.

Sorry, I follow Functional Nutritional Medicine, The docs who find out the root cause of a health issue and seek to resolve it. I see this as the future of medicine because mainstream especially the NHS appear to give a patient 5 mins and reach for the prescription pad.

I personally don't like quackwatch. Probably funded by the pharmaceutical industry.

However this is not relevant.

What is relevant is that Lindajames gets as much info re Root Canals as possible - even if in your opinion it is 'outside the box' A wide view of possibilities, a 360 degree view is always the best view. A narrow viewpoint leads to no specialist seeing the elephant in the room


Even if Quackwatch were funded by the pharmaceutical industry (and it wouldn't have such a crappy website if it were) you'd still have to explain why large government organisations like the FDA, BBB and FTC all found evidence of dodgy practices.

Now one assumption is that the whole of the US government is paid by the pharmaceutical industry to harass anybody that says anything they don't like. And that they've managed to keep this information totally secret, despite about a million people having to be in on it.

Another assumption is that people like him are money-grabbing heartless scam artists who make millions by spreading fear, uncertainty and doubt.


I'd go with the FDA, BBB and FTC being subject to influential pressure - The US Govt has huge lobbyist input from giant corporations including the Pharmaceutical Industry Giants and Agricultural Industry. Look at Monsanto, huge US, now multinational conglomerate and their practice /products happily accepted by the US government being taken to European Tribunal in Paris 2017 for Crimes Against Humanity. You can't get much worse than that.

Niavely we could say, imagine, that these agencies exist to protect the individual and the planet, this is far from the truth when profit is involved.

You have your stance hopefully informed. I have mine, also informed.

However I do not see what our differences have to do with helping Lindajames and her question.

The dental expert in interview gives an opinion on the subject of Root Canals and brings to the debate experience in practice. This again is his experience and his opinion. Would you deny anyone suffering to have access to relevant information that they can then make their own minds about, could prompt further learning/enquiry/research with the result of accepting or disregarding information.

If someone is not even aware of information they will then be unable to form an opinion on such.

I was trying to help make her aware that there is such debate. I personally would appreciate someone advising me of, enabling me therefore to persue further enquiry if wished.

You and I and others can agree to disagree, even look a little deeper and seek to research a little further and challenge our opinions. We never learn from every one agreeing with ourselves. We learn from being challenged. Progress comes about from failure, not from always being right.

I look at the medical heart attack debacle as an analogy of how fixed ideas without challenge can send us awry. When the heart attack was first definitively recognised as a condition in 1911 The doctor who defined was then looked towards for an answer for what treatment should be applied. The unfortunate doctor came up with: the heart is a muscle therefore a muscle if injured should be rested. And so treatment advised was complete bedrest with absolutely no exertion for a short period. This advice became misinterpreted and became more draconion with 6 weeks bestrest being the norm in treatment following heart attack. This approach continued for 50years - 50 years! Even though so many deaths occurred this made up treatment was never challenged until the 1960's. When NASA conducting their space programme studies and found that their fit 20yr old study participants heart function deteriorated within 2 weeks of bedrest.

This treatment approach that had continued for 50yrs and killed billions of people across the globe was quietly dropped, no recognition of or apologies and a chair suddenly appeared at the side of each hospital bed with nursing staff demanding, out of bed and brisk walk across the ward.

We can learn and keep an open mind and others should not be denied info that they can make their own mind up as to whether such info may help them.


I have just received an email today from Dr Mark Hyman - who practices at the prestigious Cleveland Clinic Ohio US. He was asked to establish a Functional Medicine Dept/influence at the hospital by the Directors of this mainstream hospital.

Just a clip

mentioning the FDA

" one of the best ways to heal head injuries is to lower inflammation in the diet. To do that, he says, you “decrease fried foods, breaded foods, and eliminate all trans fats in the diet.”

In my new book Food: What the Heck Should I Eat?, I reveal how the $1-trillion food industry contributes to nutrition confusion and sabotages your health with bogus marketing claims and misleading labels. They actually contribute to problems like inflammation that wreck our bodies and our brains.

Take trans fats, which research shows contributes to inflammation and disease like diabesity. In 2003, the food lobby coerced the Food and Drug Administration (FDA) into allowing food companies to label their products as trans-fat-free if the product had less than 1⁄2 gram of trans fats per serving.

So, the makers of Cool Whip can state that it is a trans-fat-free “food” because there is less than 1⁄2 gram of trans fat in a 2-tablespoon serving, despite the fact that Cool Whip is mostly made up of trans fats.

They can legally lie.

Finally, in 2015, the FDA ruled that trans fats are not safe to eat, or non-GRAS (GRAS is an acronym for generally recognized as safe). But they’ve given the food industry a long time to get trans fats out of products.

It isn’t just Big Food and the government that create this confusion that hijacks our health.

Says it all

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I also always go to Greenmedinfo. The site that researches all the current research so you don't have to. Everything said on this site is referenced to studies.


What a shame it doesn't actually research any scientific publications.


I believed it searches any scientific studies carried out


Obviously they didn't find any real scientific studies on the page you linked.

Proper scientific studies are those with results published in a peer-reviewed journal. Books, websites and TV adverts don't count.


I think we all know what defines a 'proper' scientific study


Lynne, thank you for responding. I know there is research about inflammation, as you said. Like fbirder, I tend to be conservative in the sources I am comfortable with, but your willingness to take time and explain other information to consider is much appreciated.


I hope you find a solution to your problems and wish you good health in the future. Thank you for raising the issue of Nitrous Oxide and the effect of on B12 which I was not previously aware of. I have now filed this info, thanks to you :)

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Thank you for this interesting debate. Like you, I tend to be quite conservative in the sources I am willing to acknowledge. I appreciate that you took the trouble to respond.


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