4 of 10 aphthous stomatitis (canker sore) patients had raised levels of antibodies to alpha-gliadin, and in 3 of these 4 subjects, the ulceration remitted on a gluten-free diet and relapsed upon gluten challenge. http://www.ncbi.nlm.nih.gov/pubmed/1753350

with recurrent aphthous stomatitis, 25% showed a favorable response to gluten withdrawal and a positive gluten challenge. http://www.ncbi.nlm.nih.gov/pubmed/7261838

I used to get multiple canker sores about once a month, lasting for a week or so. Before going Paleo/Primal, my dentist suggested using a toothpaste without SLS (sodium laureth/lauryl sulfate), and that did definitely help a lot. Brands are Rembrandt Sensitive Teeth (not sure if this one is available, and I thought it was a bit expensive), Natural Dentist (this is my favorite, and cheap too), Tom's also I think. You can just Google SLS-free toothpaste to see some options. I suppose one could use baking soda.

I, too, did notice that they were related to the general state of my immune system. In the first several months of paleo, I did see a connection with eating sugar/wheat. I, too, thought that the over-the-counter aids did not help noticeably. I actually found that honey helped a lot, just dab a bit on a couple times a day (I suspect raw honey works better, but we only ever had raw honey, so I hadn't tried processed honey). Salt-water rinses too.

I've been paleo for almost two years, and have not had a canker sore in at least a year and a half. I suspect coconut oil would probably work too, but I haven't had any canker sores since discovering coconut oil.

I used to get cancer sores if I ate a lot of citrus fruit, but other than that I haven't noticed any correlation with diet. I certainly haven't had one since I started a low carb diet, even before it was also a paleo diet, but I haven't had significant citrus since then either.

growing up as a kid i would get them all the time. In college, too. I was on SAD the whole time of course. I did however used to think that they were stress-related as it seemed that especially in college around big exams etc i seemed to get more of them.

Anyhow, in the last two or three years of WAPliving-transitioning-to-paleo i don't think ive gotten one single one.

So, on strict paleo (no dairy except for butter) i have never had a canker sore (we always called them "cold sores" by the way).

I had a lot of issues with canker sores for a couple of years while I was in the Peace Corps and chronically malnourished. I'd get them every few weeks, and they were very painful. Typically they are supposed to go away in a few days, but for me, sometimes they lasted 2-3 WEEKS. Even after I got back, I had them 5-6 times in the first year.

After going Paleo, I'd say I've had one or two minor cases in the last 18 months. (Honestly, I can't remember the last time I had one.) They go away very quickly. Not sure what causes them, and I'm under the impression that the general medical community does not really know either.

I would speculate that a typical Standard American Diet will cause irritation of the gums, leaching/malabsorption of vitamins and minerals, and destruction of beneficial bacteria that are necessary for good oral health. Brushing your teeth with fluoride toothpaste or using antibacterial mouthwash may have a negative impact as well. Again, I'm speculating.

In any case, the most effective Paleo-ish solution for me was rinsing my mouth out with salt water. Most medical websites advise a weak salt solution of something like 1tsp salt to 1 cup water, but I would load up on the salt as much as I could tolerate, and rinse for 30-60 seconds. (Not sure if my method is advisable.) It stings initially, but after the first few seconds, it stops hurting, and it feels a lot afterward. It appears to accelerate the healing process, in my experience.

At one point, I sought medical treatment because the canker sores were making me so miserable, and I did not think it was normal for them to last 3 weeks at a time. The doctor gave me a prescription for Aphthasol (5% amlexanox in an adhesive oral paste), and it worked extremely well. If I recall correctly, it cut healing times down to a few days.

I was not impressed with the OTC pain-relief meds that I tried at the time -- they didn't provide any satisfactory relief for me.

i always get a cancer sore when i break the skin on my lip. i attribute it to whatever bacteria is living in my mouth overpowering white blood cells due to the wound being constantly open.

when i was younger i used to have them erupt spontaneously, but that doesn't happen to me anymore. i think it's because i suppliment with 1000mcg b12 3-4 times a week (i'd read somewhere the b12 deficiency was a cause) but yeah it could be my paleo diet, as well.

I used to get a canker sore literally EVERY time I bit my lip. When on Paleo, I NEVER get them.

I have attributed it to sugar actually touching the sore and getting inside it. I have had a gluten / dairy free dessert after biting my lip and gotten a canker sore quickly after the sugar touched it.

Interestingly, if I try to place the food away from the sore, I can eat sugar without it having a reaction (thus is why I think it has to do with actually getting sugar inside the sore)

I used to get a few cankers per year. This week I had the first one since going Paleo four months ago. It came and went pretty quickly compared to previous ones. I don't know if there's a correlation between the short life and my diet. I'll have to give it at least a year to really be able to come to a conclusion.

I get canker sores on my tongue when I eat too much sugar (i.e. white sugar and carby crap). It's my early warning signal to start downing vitamin C and knock off eating the crap so I don't get a cold. On paleo, no canker sores. FWIW, one of the side effects of taking Adderall for my AD/HD was nasty canker sores. Not sure what the connection is, but for me sugar consumption is definitely tied to my immune system. YMMV

I might be the first dissenter here. I have suffered from canker sores for my entire life - if I ever get a cut inside my mouth I have a >95% chance of getting a canker sore. This has not changed since going paleo, in any of the versions I have tried.

I'll add another anecdote, since after all, the plural of anecdote is data. It had not occured to me until reading the original question, but I don't think I have had a canker sore since going Paleo. Admittedly, it's only been 4 months for me, but I used to get them every time I bit my lip, and I know I have bitten my lip in the last 4 months and not gotten a canker sore as a result. Interesting!

I know it's really late but I wanted to mention this for other people looking for possible help. I get canker sores that last 2+ weeks often (couple of times a month). Any sort of mouth trauma is a trigger (biting/scraping whether accidental during the day or even when sleeping). I'm not strict paleo so I can't speak for it helping but when I drink these stupid energy drinks daily I don't get the canker sores. If I stop drinking them they come back within a week. The energy drinks contain 100%+ RDA of Vitamins B3, B5, B6, and B12. I'm not sure which Vitamin is helping although xjhues (another commenter) and Science Daily point to the B12. In all likely hood there could be many reasons.

I've taken Vitamin B Complex (containing all of the above B's and more) pill supplements with no luck. I just got a sub-lingual version of the supplement to see if that makes any difference (not sure yet). Possible reason for the pill form not working is: Pernicious Anemia

That may explain some of the success with gut healing diets (e.g. paleo) reducing occurrences of canker sores.

Also, Sodium Lauryl Sulfate (a.k.a. SLS from toothpaste and mouthwash), sugar and citrus don't help either.