The number one food that causes most canker sores and how simple avoidance is all that is needed for most people to banish them for good! 
Chances are, you’ve suffered from a canker sore or two in your life. These painful, open ulcers on the inside of your lips, cheeks, or even your tongue seem to take forever to heal and can really cause some grief!
One young man I know in our community suffers excessively from canker sores. His frequent outbreaks are so bad that ulcers often occur not only in his mouth but also down into his throat. This causes severe pain even when swallowing sips of water.
Canker sores should not be confused with cold sores on your lips or nose that are caused by a virus and are contagious. This cold sore remedy works great for that type of skin issue.
Unlike cold sores, canker sores are not contagious. In most cases, they are the direct result of what you eat.
Even if a canker sore seems to be triggered by something else, like a scrape from a dental appliance like braces or accidentally biting your tongue, the underlying cause is still diet. In other words, the mouth inflammation was already present such that the wound that occurred in the mouth resulted in a canker sore!
That’s right! What you eat GREATLY affects whether or not you suffer from mouth ulcers on a regular or infrequent basis.
The Number One Food That Causes Canker Sores
Guess what frankenfood is the primary cause of canker sores in the Western diet?
That culprit would be high fructose corn syrup or HFCS. Manufacturers sometimes list it as corn sugar on some food labels.
High fructose corn syrup promotes inflammation in the body, which in turn impairs the immune system. An impaired immune system is thought to be the underlying cause of canker sores.
A person on a typical diet of supermarket foods is a prime candidate for frequent mouth ulcers. This is because this stuff is in everything. Plain corn syrup is problematic as well.
This is why eating too much fruit or fruit juice can cause canker sores as well. The sugar in fruit is primarily fructose. Surprisingly, it isn’t the acid in most cases that is causing the problem. Although, acidity may be a contributing factor.
If acid were the primary problem, drinking kombucha tea would also cause canker sores. Most people I know prone to mouth ulcers can drink kombucha regularly without issue.
TOO MUCH FRUCTOSE = CANKER SORES
Even agave nectar, which many consider a health food, contributes to canker sores. The truth is that agave nectar is best avoided. It is highly processed in a manner very similar to HFCS. It is neither healthy nor helpful in any way to the person consuming it. Stay away from it if you want to avoid canker sores!
I used to suffer from canker sores all the time to the point where I had at least one bothering me much of the time.
I haven’t had a canker sore now in over 25 years. Simply cutting out all HFCS from my diet easily accomplished this huge improvement in quality of life! In addition, I watch my intake of regular fructose from other sources like fruit.
If you start checking food labels, you will be shocked. Even commercial peanut butter and ketchup contain it. Simply switching to health food store brands will quickly rid it from your life in most cases.
How Much Fructose is Too Much?
A good idea is to limit your intake of fructose from all sources to no more than 15 grams per day. This is about half the amount of total sugar intake per day that can be tolerated without ill effects.
Dr. Richard Johnson MD in The Sugar Fix describes how important it is to limit your fructose intake for health and weight control.
To give you some idea, in a big, ripe banana, you’d get maybe 10 grams of fructose.
So, if you eliminate HFCS in your diet completely and eat no more than 1-2 pieces of fruit a day, that would be a good way to go.
Be aware also that going over the fructose limit of 15 g per day (25 g at the absolute most) can cause a canker sore very quickly. Sometimes, within a few hours, one or more can appear.
When my kids were younger and attended birthday parties, if they had even ONE Capri Sun juice or a half a can of soda they would invariably have a canker sore within a day or two. I trained them very early to only drink water.
Bottom line is that even if you control your fructose intake 99% of the time, consuming a single food loaded with HFCS can cause one of these baddies very fast.
Imagine what incredible damage a high fructose diet is doing to a person’s insides if it can cause an ulcer in the mouth so quickly!
I don’t understand. We’ve been told we should eat 5 servings of fruits and veggies every day. I try to have a fruit and veggie smoothie every morning, filled with fresh fruit, Greek yogurt, kale, avocado etc. I have to stop these when I get a sore and it’s difficult to fit in my healthy foods. How am I supposed to balance eating well and not eating fruit? I have molar reactions to dressings on salads, etc.
Just do more veggies and less fruit or at least less fruit that is acidic like strawberries, pineapple and citrus fruits (those are the worst for those prone to canker sores).
I never eat HFCS and avoid most all Gmos. I don’t think just HFCS is the cause for me. I also know plenty of people that guzzle a 2 liter of soda a day and don’t get canker. They get fat or may have other health issues, but there are sooooo many things can cause canker as a side effect. This is why it’s so hard to pinpoint each person’s root cause. Hopefully I will find my cure soon. 15 year sufferer. Convinced diet is the cure too, but maybe it’s not just the sugar for me. I hardly eat any, purposefully.
I appreciate this approach. We are too concerned with knowing every single scientific detail of everything before we can trust it. That’s a problem. Good old fashioned advice is great to hear sometimes. Just use common sense and judgment.
I seriously question if this information in this article is true. This sounds more like a biased piece than anything with factual information. And your response to the comment asking for facts was “observe what happens.” Now I completely agree that HFCS is awful for you, and it may cause canker sores for some, but to base this entire article on that it’s mainly HFCS is false. I rarely eat anything with HFCS in my foods and I get them all the time. I believe mine are caused by tomatos, which is apparently common because it’s an acidic food.
Yes, acidic foods cause canker sores as well. The article isn’t meant to suggest that HFCS or eating too much fructose from any source (including fruit) is the ONLY source of canker sores.
Drink unsweetened black tea. I used to suffer miserably for about 25 years. Then I discovered a “cure” or treatment that worked wonders. If I fell a sore starting or if I have an abrasion in my mouth that I fear will ulcer out or become a canker sore I immediately do the following for almost instant relief or a preventative. Stop all soda consumption. Stop juices. Do not consume any chips especially sharp corn chips or tortillas. Eat bland plain foods without salt or spice and avoid any foods that make the spot burn. Avoid getting toothpaste on the sore. Now here is the most important thing consume unsweetened black iced tea with every meal and keep a glass handy to sip on every 5-10 minutes in between meals. You will find that the pain and swelling stops almost immediately and that the door starts to heal. Do not put any salves creams gels or other over the counter preparation on it. Such may provide momentary pain relief but actually delays the healing. Following the above stops my suffering immediately and heals a sore in a day or two. Good luck
Try unsweetened black iced tea as a pain reliever and aid to fast healing. I used to suffer miserably but no more. If I start to get a sore or if I get a small abrasion in my mouth I immediately cease drinking all forms of soda, eliminate all chips, fruits and juices. Eat bland simple food with black iced tea unsweetened. Also in between meals sip on the tea and you may find quick relief. It has never failed for me after suffering over 20 years
Do you know of any independent peer-reviewed scientific studies that has confirmed this link?
Observe what happens. You eat too much fructose (fruit, fruit juice or candy/sweets loaded with HFCS), bang you get a canker sore very quickly. If I eat pretty much anything with HFCS in it, I get a canker sore almost within an hour. If a person is predisposed to them, excessive fructose brings them on quickly.
I also get canker sores easily and avoid almost anything with sugar. This does keep me slim, but I do miss eating some desserts. One thing that has helped prevent them is taking Agrisept-L, “the original grapefruit extract”. Just 3 drops in my water at night prevent these most of the time. Prior to taking Agrisept-L, it was rare that I wouldn’t have a canker sore, now it is rare that I have one. I have been using Agrisept-L for about 10 years.
I have had these sores in my mouth all my life. I found acidophilus milk helps a lot. The acidophilus pills do not help at all. The L-Lysine pills only work if you take them at the very beginning of a sore. I have had up to 30 of these sores in my mouth at a time when I was child. The pain is unbearable. Sometimes I will run a fever when they are at their worst. I have very little sugar in my diet and eat heathy, yet I still get them. I did find if I drink any kind of soda, diet or regular, I get numerous painful sores in my mouth by the very next day. This is when only drinking about a fourth of a can of soda. I stay away from soda totally now. I have a sore on my tongue right now that has been their for 2 weeks. I can hardly speak because of the pain. I have been to numerous physicians all my life. No one has a real cure. I wish everyone the best!
I wish there was really a cure for this awful condition. Everything you read says something different. I have been suffering with canker sores for years and it just seems to be getting worse. My breakouts can last up to 7-10 days with 7 to 10 sores at one time. It’s painful to eat, drink, and talk. These things are the worst. I’ve tried the B12 supplements, the toothpaste without the sulphate blah blah. I’m just so frustrated. I will try the Lysine and cut down on the fructose and see if that works. I really hope it does.