The People's Perspective on Medicine

Can Kiwi Fruit Overcome Horrible Canker Sores?

Many readers report that eating kiwi fruit can help horrible canker sores heal quickly. Perhaps the anti-inflammatory compound actinidin is responsible.

Canker sores (aka aphthous ulcers) are painful spots that appear on the tongue, inner lip or lining of the cheeks. Unlike cold sores, which are caused by herpes virus, canker sores are not associated with any bacteria, virus or fungus so far as we know. Sometimes they just appear mysteriously. At other times, they are the result of an injury to the mouth or tongue, such as when you bite your cheek or eat some sharp chips that abrade the tongue. What can you do about horrible canker sores?

Overcoming Horrible Canker Sores:

Q. For as long as I can remember, my family and I have suffered off and on with horrible canker sores. We finally realized that eating nuts or peanut butter appeared to trigger this problem.

Often, L-lysine didn’t work. I read in your column that eating kiwi fruits helped prevent canker sores. I love kiwis so I decided to try it.

Lo and behold, I can now eat peanut butter, pistachios, pecans and peanuts as long as I eat a kiwi within a day of consuming the nuts. I haven’t had a canker sore in four years.

Kiwi Fruit to Heal Horrible Canker Sores:

A. You are not the only reader who has reported success eating kiwi fruit to prevent or speed healing of canker sores. Scientists have not specifically studied this activity of the green fruit with the fuzzy brown skin (Actinidia deliciosa). However, they have found that an extract from a related fruit, Actinidia arguta, can alleviate skin inflammation through its impact on immune system compounds and cells (Nutrients, Oct. 2, 2018). Perhaps similar activity helps heal canker sores.

Other research has shown that people eating SunGold variety kiwi fruit increase their levels of vitamin C and experience changes in their gut microbes (Nutrients, July 12, 2018).  We don’t know if the balance of microbes in the mouth is also altered. If it were, the change might potentially contribute to the healing properties of kiwi fruit for canker sores.

Other Readers Report Success Eating Kiwi Fruit for Canker Sores:

Q. Thanks to the People’s Pharmacy, I have had wonderful luck with kiwi fruit to treat canker sores. I peel and slice a ripe kiwi, then hold each slice against the sore(s) with my tongue for a minute or so before chewing and swallowing it. Usually, I feel relief within an hour.

In the uncommon event that the canker sore persists, I eat another kiwi the same way, the next day. It has never taken more than two kiwis for me to banish a canker sore, and I must say, I find it much more pleasant than another remedy you write about: sauerkraut juice.

How Might Kiwi Fruit Be Working?

A. Over the years we have heard from numerous readers that eating kiwi fruit as you describe can heal horrible canker sores quickly. We’ve never had an explanation for this terrific remedy.

Kiwi for Bedsores:

We still don’t, but we may be getting a bit closer. We were fascinated to see a randomized clinical trial comparing kiwi fruit extract to normal saline solution for the healing of bedsores (Mohajeri et al, Indian Journal of Surgery, Dec. 2015, Supplement 2).  The study was small, with only 40 patients, but the differences between the two groups were significant. Although the skin and the surface of the tongue or cheek are different, both are epithelial tissues.

Kiwi for Burns:

Apparently the protein-dissolving enzyme in kiwi fruit, actinidin, can help speed healing. Kiwi extract has also been found helpful in healing burns (Mohajeri et al, Surgery, Nov. 2010).

Josh, a dentist, has a suggestion for preventing canker sores:

“Exciting to think that the little old kiwi fruit could treat the symptoms and longevity of a canker sore. But, what might have caused the canker sore?

“I am a practicing general dentist and I’d like to advise all of the readers that DO get canker sores to immediately change their toothpaste. Nearly every name brand toothpaste contains sodium laurel sulfate (SLS) – a common detergent. Turn over your bottle of hair shampoo. One of the first three ingredients will be SLS. This ingredient throws off the balance of your mouth and your body then needs to repopulate certain bacteria and neutralize your mouth. For some people, the temporary imbalance can yield canker sores.

Weleda, JASON, Burt’s Bees and Dr. Ken’s are a few of the companies whom manufacture SLS-free toothpaste. Switch your toothpaste and you will notice a serious drop in canker sores.”

Karen offers another explanation for some horrible canker sores:

“I am gluten intolerant and end up with a canker sore in my mouth when I have eaten gluten by mistake.”

Art had a similar experience:

“I had continuous canker sores my whole life until at age 80 I discovered I had Celiac disease (another story).

“Since going to a gluten-free diet I have not had even one canker sore. A gluten-free diet also almost totally eliminated acid reflux for me.”

Jim suggests a completely different canker sore remedy:

“I’ve always used powdered alum (a spice used in pickling) for canker sores – wet finger slightly, dip in powder and press on sore. Let spittle drain into sink for about a minute. Rinse. I think it puffs up the sore allowing it to heal but probably has some analgesic properties as well. I seem to get canker sores when traveling so keep a little container of powder with me.”

Keep in mind that alum contains aluminum. Consequently, you might not want to use it frequently, as we fear that excessive exposure to aluminum is not good for your health.

Another reader offered this simple approach:

“For canker sores, I have used table salt on a dampened finger and held it on the sore a minute. If the sore is where I can dry it first, it works better. This helps mine heal very quickly. It has been years since I have had one.”

Sauerkraut for Canker Sores:

Q. My husband has horrible canker sores in his mouth all the time. The doctors he has seen say there’s no cure, so he has to live with it. What can you recommend? He has tried many topical remedies, plus some prescription drugs, but he is not sleeping well due to the pain. How can he get relief?

A. While eating kiwi fruit is one popular remedy, other readers may prefer a different approach.

Here’s another testimonial:

“Sauerkraut juice has worked like a miracle for me! It starts clearing up a canker sore within hours, and the sore usually healed by the next day. One caveat, though: juice from canned sauerkraut doesn’t work nearly as well as the fresh stuff (in the refrigerated deli section).

“It’s such a weird remedy that I did some research on sauerkraut to see why it might work. Sauerkraut is fermented (like yogurt or sourdough) and is full of probiotics. I’ve discovered that if I sip a little sauerkraut juice every couple of days I don’t develop canker sores in the first place.”

You’ll find other options for treating canker sores (including sauerkraut juice) in our book, The People’s Pharmacy Quick & Handy Home Remedies.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
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I find that taking L-Lysine works wonders for canker sores. Also swishing with diluted hydrogen peroxide.

Extra thank you to Josh the dentist for explaining the dangers of Sodium Laurel Sulfate.
Been known danger for decades yet many people still do not know or understand/

I used to get a fair amount of canker sores years ago. But for several years I have been taking a Multi Vitamin, extra B-12, D-3, Natural Vitamin E, Lipsomal Vitamin C, K, B Complex. I take D- Mannose for preventing Urinary Tract Infections, Lots Of Probiotics, Turmeric. And since starting these several years ago I don’t get canker sores anymore.

I think they are caused by a vitamin or mineral deficiency. That is my educated guess. And if the Kiwi clears them up and/ or prevents them, maybe it’s a Vitamin C deficiency causing them? People like to think that their diet provides all the vitamins and minerals they need but the sad truth is that it doesn’t. The quality of our food supply has gone way downhill. Everything now is genetically modified. The soil has been seriously depleted of nutrients; prepared foods contain so much junk and chemicals, and it seems there is more junk and chemicals in prepared food than there is food.

Just those three things makes our foods very poor quality. Not everybody can afford to eat everything Organic. But even organic foods have to grow in that depleted soil. So take vitamins and supplements to make sure you are not deficient in vitamins and minerals. Some doctors tell patients they don’t need vitamins but don’t listen to them. Read and educate yourself. That will pay off big time in how healthy your body is.

I get mouthsores as a side effect of a medication. They were coming less frequently. Then I decided to see what pills I could cut out of my regular morning routine. I stopped my multivitamin, and a few days later the mouth sores came back. I read online that a vitamin B deficiency could be a cause of canker sores. I started back on the vitamins, and I haven’t had a sore since. Gargling with salt water and having the right toothpaste have provided relief, too.

I used to have a mouthful of canker sores all the time. Then I gave up eating wheat flour and was surprised to realize that my canker sores were gone. Small amounts of whole wheat flour don’t seem to bother me. It is mostly foods containing white flour.

I used to have very painful canker sores until I started taking red raspberry leaves for a once a day supplement. After about 6 months, I realized that I was not getting canker sores any more. It has been 20 years, and I still do not get them, and I am still taking a daily red raspberry supplement. It was also helpful for a dear friend of mine suffering mouth sores from chemo.

Like the comments from the dentist listed above, I highly recommend changing your toothpaste. I have had canker sores since I was a child. When I discovered that SLS (sodium laurel sulfate) was the cause of my canker sores, I changed toothpastes. Always look at the ingredients on the back of the box. I have found the right toothpaste and have been canker sore free for years. What a relief!

Most of the time, I take Lysine as I don’t seem to get enough in my diet, and it really helps with canker sores. I still get them occasionally from overly acid foods or when my stress levels are high. If they seem stubborn about going away I rinse and spit with a little bit of Peroxide. I re-rinse with water afterwards until the taste is gone, and they seem to go away almost immediately. Do this carefully, and don’t swallow!!!

I would get bad canker sores often as a child, and then periodically after that. Finally a pattern emerged: As a child I drank a LOT of OJ: (frozen concentrate from a can), then not so much later. Sure enough, I get a sore whenever I consume any kind of processed / canned citrus juice or fruit. Fresh juice doesn’t bother me, nor fresh oranges. Fresh grapefruit does. When I get a sore, applying a propolis mixture alleviates and speeds healing. Kiwi sounds like another pleasant alternative.

My mom treated our canker sores with sodium perborate, over 60 years ago. Just at bit on the sore at bedtime, and the sore was gone in the morning. I don’t know if drugstores still sell it or not; my bottle is ancient, non- prescription, but I still keep it on hand, and it still works.

Miracle cure? Dabbing the sore with a styptic pencil cured my canker sores within 24 hours and don’t have them any more.

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