Do People with Interstitial Cystitis Need to Avoid Vitamin B6?
In the last blog post, I discussed whether people with interstitial cystitis need to avoid vitamin C. Today’s post is going to focus on a very similar topic: do people with interstitial cystitis need to avoid vitamin B6?
To reuse my introduction from last time, I have noticed that there is a lot of confusion among interstitial cystitis sufferers about vitamin B6 and whether or not it should be avoided. I hope to clear up some of that confusion today!
The succinct answer is that people with IC do not need to avoid foods that are naturally high in vitamin B6. They might wish to avoid foods artificially fortified with vitamin B6. They should avoid supplements that use the pyridoxine form of vitamin B6. And they may or may not need to avoid supplements that use the P5P form of B6. If that’s all you wanted to know, you can stop reading now! If you’d like to know more, the more detailed explanation is below.
Most people with interstitial cystitis or painful bladder syndrome soon come across the advice that vitamin B6 can exacerbate symptoms. Within the community of bladder health patients, this is fairly mainstream information. However, people don’t always encounter the properly nuanced version of the advice, which is that supplemental B6 can exacerbate symptoms, but the B6 that occurs naturally in food does not. As a result, I sometimes get people mistakenly telling me in quite a matter of fact way that they have to avoid such and such a food because it contains B6 which will irritate their bladder. This means that as well as losing out on this important vitamin in supplement form, they’re also unnecessarily restricting their dietary access to it.
As with vitamin C, there are different forms of vitamin B6. Vitamin B6 is actually the umbrella name for a group of six pyridine compounds: pyridoxine; pyridoxal; pyridoxamine; pyridoxine 5’phosphate (PNP); pyridoxal-5’-phosphate (P5P, also known as PLP); and pyridoxamine-5’-phosphate (PMP). As I discussed in one of my very early blog posts, A Bladder Friendly Form of Vitamin B6?, the first three types of vitamin B6 cannot be used by the body without being converted into the active coenzyme P5P form. However, most dietary supplements and fortified foods use pyridoxine, which you might see listed on labels as pyridoxine hydrochloride or pyridoxine HCl.
The pyridoxine form of vitamin B6 is known to irritate the bladder in many people with interstitial cystitis. Nobody knows why it does this, but plenty of people report it happening. Supplemental pyridoxine has also been linked to toxicity symptoms, most famous of which is peripheral neuropathy. For this reason, people with interstitial cystitis and other painful bladder conditions should avoid supplements containing the pyridoxine form of vitamin B6. I would personally extend this warning to other genitourinary conditions, including overactive bladder, urinary retention and persistent genital arousal disorder.
Whether or not you avoid foods fortified with vitamin B6 is up to you. It is likely to depend on how sensitive to pyridoxine you are and how many fortified foods you eat. To give you some idea of scale, I like to see 20 – 50mg of vitamin B6 in a good quality multivitamin product (although I most definitely don’t like to see it in pyridoxine form). The EU Nutrient Reference Value for vitamin B6 is 1.4mg. Thinking about some of the brands that people in the UK might choose when they first decide to take multivitamins:
- Boots A-Z Tablets for general support contain 1.4mg of vitamin B6 as pyridoxine.
- Centrum Advanced 50+ Multivitamin Multimineral Tablets contain 2.1mg of vitamin B6 as pyridoxine.
- Holland and Barret Multivitamins and Iron Tablets contain 1.4mg of vitamin B6 as pyridoxine.
- A single slice of Kingsmill 50/50 Vitamin Boost Bread contains 0.23mg of vitamin B6, form not specified.
- A serving of Ready Brek contains 0.36mg of vitamin B6, form not specified.
- A serving of Kellogg’s Rice Krispies contains 0.36mg of vitamin B6, form not specified.
You’d therefore need to eat almost four servings of Ready Brek or Rice Krispies, or six slices of Kingsmill 50/50 to get as much vitamin B6 as is present in the above Boots or Holland and Barrett multivitamins. Meanwhile, you’d need more than 55 servings of the two cereals or more than 86 slices of the bread to get as much vitamin B6 as provided by a multivitamin offering 20mg!
I imagine most people aren’t eating vast amounts of fortified bread and cereal each day, so whether or not you need to avoid them probably depends on how sensitive you personally are to B6. You might find that you can eat them without issue since the amounts of B6 involved are relatively small; however, if you do eat fortified foods on a regular basis or know you react to even low amounts of pyridoxine, it might be worth switching to non-fortified brands for a while and seeing if that helps. It is something to keep in mind and to always check food labels for in any case. Given the kinds of foods that tend to be fortified in the first place, it might also be worth reading this blog post about the dietary interventions I recommend for people with chronic health conditions and seeing if you can think of something else entirely to eat for a while!
Foods that contain naturally occurring vitamin B6 do not need to be avoided unless they themselves trigger your bladder symptoms. For example, 100g of chicken breast contains 0.9mg of vitamin B6, but chicken is, for most people with IC, a safe food. However, 100g of tinned tomatoes contains 0.15mg of vitamin B6 and tomatoes trigger flare ups of symptoms in many IC sufferers. Therefore, it is the food itself rather than its vitamin B6 content that determines whether avoidance is necessary for bladder pain patients. Regarding vitamin B6 toxicity in general, this article reassures us that “intake of food-based sources of pyridoxine will not cause toxicity. The only reported cases of vitamin B6 toxicity are from supratherapeutic dosing of supplements or iatrogenic”.
Foods high in vitamin B6 include beef and beef liver, chicken, turkey, pork, salmon, tuna, tofu, chickpeas, spinach, kale, avocados, bananas, papaya and oranges. As those of you familiar with the IC Diet will know, some of these are considered bladder-friendly foods and some of them are not. Their vitamin B6 status is seemingly irrelevant in determining whether they appear on the safe list or the triggers list.
Although most food supplements offer B6 in its pyridoxine form, several do use P5P instead. You can find P5P in some brands of multivitamins, in some brands of B complex, and also in single-nutrient products. Maddeningly, six years after writing my first vitamin B6 post, I still cannot find out conclusively whether a majority of IC sufferers find P5P triggering to their bladder or not. Understandably, many people, upon being told that general vitamin B6 might trigger flare ups, are unwilling to risk any form of vitamin B6 again. I might have been among them except for the fact that my own bladder does not react badly to small amounts of pyridoxine – I simply thought it might be an aggravating factor in my PGAD – and I experience bad PMS if I become low in B6. As detailed in that first B6 post, I therefore steered clear of all B6 for a while, then tried a P5P supplement, was absolutely fine with it, and now use both a multivitamin and a B complex that contain B6 in P5P form. I have thought about replacing these with Tiny Pioneer Multi Female and adding a separate P5P supplement to it, but I do pretty well on my current regime and can’t be bothered with an overhaul at the moment.
Most side effects from supplemental vitamin B6 seem to either relate to pyridoxine or not state which form was used. For example, this article at Frontiers links B6 to the onset of bladder problems in a patient with no history of interstitial cystitis, but does not specify whether pyridoxine, P5P, or some other form was used. Given pyridoxine’s status as the most commonly used supplemental form of B6, it seems reasonable to assume that a majority of articles linking B6 supplementation to side effects or toxicity will have used pyridoxine. Furthermore, given the relative scarcity of P5P in oral supplements, it is also reasonable to assume that in cases where it is used and has caused issues, that fact itself would be noteworthy enough to state explicitly. With that being said, there are some people with vitamin B6 toxicity who are unable to tolerate either pyridoxine or P5P. Others are eventually able to tolerate small amounts of P5P, but not pyridoxine. I have gleaned this through anecdotal comments left on blogs and forums rather than through published papers on the matter, of which there is a striking lack.
I absolutely do not purport to be an expert on vitamin B6 toxicity, so I have no opinion on the suitability of P5P for people who have developed neuropathies or other side effects subsequent to using pyridoxine. I am also unable to give a definitive answer about the suitability of P5P for those with interstitial cystitis, because there are simply no published case studies or official trials into the matter. All I can tell you is that my own bladder (and also my PGAD), which reacts so strongly to ascorbic acid, is fine with P5P in doses of up to 75mg a day, albeit split into two servings. I have also read individual anecdotes where people with IC have been able to tolerate or indeed have found helpful P5P. One such anecdote is at the bottom of this page on Ray Sahelian’s website.
As ever, interstitial cystitis is never a straightforward or one-size-fits-all condition. Although many, many sufferers find he pyridoxine form of vitamin B6 triggering and the jury is out on how many of those would be able to tolerate the P5P form, you will find several people who claim to find B6 helpful. Even more confusingly, you will find several who find other B vitamins triggering, even though many IC patients are fine with all except B6!
If you know you find vitamin B6 triggering to your bladder, but wish to take the other B vitamins, you can use a B Complex without B6 such as Tiny Pioneer No 6, Please!. If you find even B complexes without B6 triggering, then chances are one of more of the others is problematic. In this case, if you wished to supplement with some B vitamins, you would need to try taking them one at a time as single nutrient supplements to try to figure out which the offending ones are. If you have found pyridoxine triggering, but have some reason why you would still like to supplement with B6, I would recommend waiting until your bladder symptoms are well controlled and then adding very small amounts of a clean, single nutrient P5P product into your normal regime. If you are okay with a small amount, you could gradually increase the serving size until you are at whatever your preferred daily amount is. Only then should you change your daily regime to incorporate new products that contain P5P as part of a multivitamin complex.
I’m sorry that I can’t provide clear answers to all of the B6 confusion. To summarise, my thoughts are:
- Yes, avoid pyridoxine.
- Be aware of fortified vitamin B6 foods and consider avoiding them if they seem to flare your bladder symptoms.
- No need to avoid foods naturally high in vitamin B6 unless they are known IC triggers.
- Some IC patients are okay with P5P and even find it helpful; others might not be. There is no conclusive research on what is true for the majority of bladder pain patients. If for some reason you feel that in spite of your IC you want to supplement with B6, starting with small amounts of P5P and seeing how you get on is probably the best way to do it.
I hope this helps a bit!
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