Anyway so where do canker sores come from?

The exact cause of canker sores (also known as aphthous ulcers) is unknown, but the following may contribute to their development:

• Acidic fruits, citrus fruits
• Not getting enough sleep
• Illness
• Stress
• Hormone changes
• Losing weight too quickly
• Food allergies
• Vitamin Deficiencies
• The foaming agent Sodium Loreth Sulfate, often found in toothpaste.
• Rubbing of teeth against gums
• Accidental biting of lip

So as a canker sore sufferer, you may have to do a bit of experimentation to see what has a positive effect.

Using a non SLS toothpaste, taking vitamin supplements and getting more sleep are no-brainer things that you can do which will probably benefit you in other ways. Sometimes these things are easier said than done as it takes habit and discipline to decide to have more sleep and do less work / socialising / watch TV etc. or whatever else is distracting you.

Unfortunately there is not much known about the exact causes of these sores or why some people get the more than others. Doing your own experimentation may help you to find what works for you, applying common sense. Be careful if you are thinking of changing your diet to help, it would be worth seeing a dietitian before embarking on such a venture. Radically changing what you eat could cause other problems and your whole health should be looked at in regards to your diet, not just preventing canker sores.