Toothpaste with honey can be purchased in stores: “Very interesting that this is actually allowed,” says researcher

“Throughout my working career, there have always been professionals who have claimed that honey is good for teeth. They have, of course, been overruled,” says Elin Giertsen.

At the University of Oslo's Faculty of Dentistry, Giertsen is scrolling through Google results.

Alternative toothpastes are sold in health food stores, among other places – both over the counter and online.

Giertsen is now a retired professor who still works. During her 44-year career, Giertsen has been part of a dramatic development in Norwegian dental health.

Fluoride has gained a foothold in Norway and reduced dental problems in young people to a fraction of what they once were. The public has also become more aware of what sugar does to teeth. Norwegians generally have good teeth despite a high sugar intake.

That's why she is concerned when she sees that part of the population does not listen to advice from professionals.

No documented effect

When Giertsen first discovered that health food stores were marketing toothpaste with manuka honey, she thought it must be an extract and that the sugar had been removed.

That was before she realised that the products state that they contain manuka honey in its pure form. Sugar, in other words. Some of these toothpastes are also fluoride-free. They are often marketed towards people who are sceptical of fluoride.

An argument that is common among manufacturers is that manuka honey is antibacterial. This is true in and of itself. Manuka honey contains methylglyoxal (MGO), which is known to kill bacteria.

Toothpastes with manuka honey are simply one variant of what Giertsen refers to as natural toothpastes.

Aloe vera, coconut oil, and more

Giertsen has written about this issue in an article in the Norwegian Dental Journal (link in Norwegian). Some of these natural toothpastes contain fluoride, others do not.

Giertsen's review shows that some of these toothpastes have added fluoride. But they often contain smaller amounts of fluoride than recommended. This also means that they provide less protection against the development of caries than regular fluoride toothpastes. Caries is better known as cavities.

Natural toothpastes contain extracts and oils from various plants as additives, including aloe vera gel or coconut oil.

There is still no scientific documentation that these additives promote oral health, Giertsen wrote in the article.

"Leads to tooth decay"

Giertsen is particularly concerned about the use of manuka honey. She describes it as gross misinformation when manufacturers write that manuka honey protects teeth from caries. Honey has no place in a toothpaste, Giertsen says.

“Honey contains many protective components, by all means – but in very small amounts. So it’s not true that the sugar in honey is healthier than other types of sugar,” she says.

“Honey leads to tooth decay just like regular table sugar,” she says.

Giertsen adds that many of the substances used in regular fluoride toothpaste also have antibacterial effects.

Fluoride has an effect, but not other ingredients

Both regular fluoride toothpaste and natural toothpaste contain essential oils and soap substances, Giertsen points out. They are designed to provide the desired taste and foaming effect. The substances can be antibacterial. But they do not affect oral health, according to Giertsen.

“Fluoride is what has an effect against the development of caries,” she says. “There's absolutely no reason to use toothpaste with sugar in the morning and evening.”

She believes this can be especially bad for children whose teeth are still developing, or for older people who have little saliva in their mouths.

“It’s simply worrying that this product even exists,” says Giertsen.

Tested on skin – but not on teeth

Sunkost is Norway's largest health food chain. They sell a manuka toothpaste with fluoride.

Giertsen can’t believe that Norwegian authorities have not done anything about this.

“It's very interesting that this is actually allowed. That's why I wrote about it. But why is there no reaction when this toothpaste is being sold over the counter at large retail chains?” she says.

Sunkost, for its part, believes they have solid research documentation for the toothpaste they sell. You can see Sunkost's response further down in the article.

The Directorate of Health is concerned

The Norwegian Directorate of Health is not specifically familiar with the toothpastes that contain manuka honey. Nevertheless, they are not positive about consumers being able to buy toothpaste with honey.

“No, honey is a type of sugar that can cause caries,” says division director Helen Brandstorp.

"Can consumers be misled by such products in stores?"

“Yes, and the Directorate of Health agrees with the concerns raised by Professor Elin Giertsen at the University of Oslo,” says Brandstorp.

The same is true of the Norwegian Dental Association.

Not enough antibacterial properties

“We share Professor Elin Giertsen's concern. Toothpastes that contain honey – and therefore sugar – can pose a risk of caries,” says Camilla Hansen Steinum, head of the Norwegian Dental Association.

She also points out that manuka honey can have an antibacterial effect, but:

“It also contains sugars that cause bacteria in the mouth to increase acid production. This increases the risk of caries, and the effect is not canceled out by the antibacterial substances in the toothpaste,” she says.

“Even if the product contains fluoride, which is positive and preventive, sugar in a toothpaste will still be inappropriate and professionally difficult to defend,” says adds.

Only tested for skin irritation

“It says that the toothpaste at Sunkost is dermatologically tested. What does that tell us?”

“The fact that a product is dermatologically tested only means that it has been assessed for whether or not it causes skin irritation or allergic reactions,” says Steinum.

“It says nothing about the product's effect on oral health. It's not relevant as documentation for preventing caries. Many cosmetic products use dermatological testing as marketing. It has limited relevance when it comes to dental health,” she explains.

Steinum sees that there is greater interest than before in products that are marketed as ‘natural’ and ‘pure.’ She supports Giertsen in that fluoride is the most important thing when choosing which toothpaste to brush your teeth with morning and evening.

No requirements for demonstrating a clinical effect

Steinum finds it problematic that toothpaste is regulated as cosmetics. This is true not only in Norway, but throughout the EU.

“That means there are no requirements to document a clinical effect – only safety requirements. From a professional standpoint, we believe this is a weakness,” says Steinum.

She points out that toothpaste is used daily and has a direct impact on people's dental and oral health.

“There's a solid knowledge base for what actually prevents caries. We would like to see regulations that place greater emphasis on documented health effects,” she says.

She believes that the regulations as they stand today allow retailers to sell products that do not have an effect, or even products that are harmful.

Must be documented

The regulations require that toothpastes must be safe under normal use, according to Charlotte Holkov at the Norwegian Food Safety Authority. She is a senior adviser in the section for chemical food safety.

The Norwegian Food Safety Authority does not wish to comment on individual products. They respond on a general basis.

“Claims on cosmetic products must be truthful, documentable, and not misleading, in line with the EU's cosmetics regulations,” Holkov writes in an email to Science Norway.

“The manufacturer must be able to substantiate all claims, including general expressions such as ‘dermatologically tested’ with relevant documentation,” she writes.

Sunkost responds

Sunkost has been informed of Elin Giertsen’s concerns about their product.

“We take all professional claims and warnings seriously, but there are good reasons for using manuka honey in this product,” Live Kjenner, Sunkost AS marketing director, writes in an email to Science Norway.

She maintains that manuka honey differs significantly from other honey.

She refers to several studies on the effect of manuka honey on bacteria in the mouth. You can find them in the fact box at the bottom of the article.

The studies show that manuka honey differs significantly from other honey. They contain substances with documented antibacterial effects, writes Kjenner.

Giertsen agrees with this, but points out that all honey is antibacterial.

Kjenner further writes that several studies show that manuka honey behaves differently in the mouth than other sugars.

Giertsen believes this is wrong.

Not without reservations

“It's not true that manuka honey behaves differently in the oral cavity than other free sugars. Animal studies on rats have shown that a solution with ten per cent honey leads to tooth decay, just like a ten per cent sugar solution,” Giertsen says.

Kjenner at Sunkost further writes that manuka honey does not appear to promote the growth of bacteria that cause caries. On the contrary, manuka honey appears to inhibit them and reduce the amount of plaque.

“This is specifically linked to the honey's unique methylglyoxal MGO content,” writes Kjenner.

“Yes, it's true that manuka honey and other types of honey inhibit oral bacteria in experiments performed on a lab bench. This has been shown in countless lab studies. It's also well known that the powerful antibacterial effect of manuka honey is linked to its high content of MGO,” is Giertsen's response.

“It's important to note that one cannot draw conclusions about clinical efficacy based on results from lab studies,” she adds.

May contain half as much sugar as soft drinks

Sunkost further writes that very small amounts of manuka honey are used: one to five per cent. The amount of toothpaste actually used per brushing is low:

“The total sugar content that the teeth are exposed to therefore becomes marginal,” according to Kjenner at Sunkost.

“This is incorrect,” says Giertsen. 

She compared it to soft drinks, which often contains ten per cent sugar.

“Rinsing your mouth with a one to ten per cent sugar solution leads to strong acid production by bacteria on the teeth. This leads to dissolution of the tooth surface. Very small amounts of sugar are enough for plaque bacteria to convert the sugar into acids,” says Giertsen.

———

Translated by Nancy Bazilchuk

Read the Norwegian version of this article on forskning.no

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