Deciphering Canine Dental Health: What Works and What Doesn't - Natural Dog Supplements and Superfoods by Fetched

Deciphering Canine Dental Health: What Works and What Doesn't

by Tudor Nikolas on Jul 16, 2023.

We have done a lot of research of the current evidence base on Pubmed prior to formulating our proprietary dog teeth cleaning formula.  While doing our research, we have also come across numerous claims about the benefits of different “superfoods”, but with no scientific backing. Some of these articles on various popular canine health websites, don’t even have any references to support these claims.

Although there is currently some regulations with regards to pet supplements out there, the industry is nowhere as regulated as for humans. This means you have to be careful, do your own research, and judge everything with a pinch of salt.

I now wanted to share some of our comprehensive research with you, specifically on what ingredients have the most scientific evidence backing for working as plaque removers in dogs.

I will also share those that tend to be more of a gimmick and don’t actually help with anything other than sounding fancy! One of these ingredients, which is present in two of the common teeth cleaning products for dogs, could actually do more harm than good.


One emerging trend in general health foods and supplements for dogs is the use of natural remedies. Seaweed in particular is leading the charge in this area. Particularly noteworthy is its role in oral health and teeth cleaning.

Seaweed is not a newfound fad. In fact, it has been an essential part of the human diet for centuries. Due to ease of access, this was mostly the case in coastal communities, and it has become essential due to its rich nutritional content.

What's less known, is the substantial benefits it can offer our pets, especially when it comes to dental health.

Let's start off with the main player:

Ascophyllum nodosum

Most of the magic lies in a certain species of seaweed, known as Ascophyllum nodosum. When ingested, it has specific bioactive compounds that act in the dog's saliva to break down plaque and tartar naturally.

This interaction and breakdown of plaque and tartar is what  ca reduce bad breath, and promote healthier gums and teeth in dogs.

So what’s the evidence?

The latest study to look at the effects of Ascophyllum nodosum is from 2021. In this study, 60 dogs were randomised to either a control group, or treatment group with a powder containing Ascophyllum nodosum.

Mass spectrometry was used to measure the changes in saliva before, and after 30 days of daily supplementation with Ascophyllum. This study found that there were less plaque forming metabolites in the treatment group, than the group treated with a placebo.

This study supports the evidence that using this particular seaweed on a daily basis, could reduce the development of plaque and tartar on a dog’s teeth.

However, they do comment that the exact mechanism through which this is achieved, is unknown. (source)

In addition to the powder, this 2018 study was done on chewable treats containing Ascophyllum. This also showed efficiently decreased plaque and calculus accumulation in the dogs that were treats containing Ascophyllum nodosum, but in this case after 90 days.

Again, no mechanism of action was identified, but it was hypothesised that the effects are more likely to be occurring systemically, rather than through a direct and local effect on the teeth.

Both of these placebo controlled studies concluded that Ascophyllum nodosum supplementation may be an effective way to reduce bad breath and to maintain good oral health in dogs.


The term Spirulina encompasses two blue algae (Arthrospira platensis, and A. maxima) that have been consumed by humans for centuries.

A 2021 study conducted in U.S. showed that dogs whose diet is supplemented with Spirulina have shown an enhanced immune response and better gut health compared to dogs in the placebo group.

There were higher vaccine response rates after given their rabies vaccinations and also a significantly increased gut microbiota stability.

It is therefore likely that there could even be a synergistic effect between Spirulina and a dog probiotic supplement.

With regards to dental health, there are several studies that show the benefits of Spirulina, done on humans.

This study from 2013 shows promising anti-inflammatory effects which can help with the conservative management of periodontitis without any side effects. The beneficial effect is thought to be from its high levels of antioxidants.

Another study from 2017 showed that regular use of a mouthwash infused with Spirulina resulted in significant reduction of dental plaque and gingivitis. This study however was not placebo controlled.

Overall, the benefits of Spirulina in dogs seem to be described best in the first 2021 study I mentioned a few lines up. These benefits are related to a better immune response, improved gut health and its antioxidant effects.

The antioxidant benefits are especially important as several studies points towards their effects in restoring good cell metabolism and neutralizing excess free radicals, which may have a role in cancer prevention and overall longevity. (source)

Fucus Vesiculosus (Bladderwrack)

Fucus is one of the most prominent brown algae, found mostly in the Northern Atlantic and Arctic region.

Same as with Ascophyllum nodosum and Spirulina, it is very rich in minerals, vitamins (A, B1, B2, B9, B12, C, D, E, and K), protein, essential amino acids and essential minerals. Their rich content of polyunsaturated fatty acids and polyphenols means they exhibit anti-oxidant and anti-inflammatory properties, as hinted at before. (source

They are also thought to have anti-tumour activity and are currently being researched as potentials for anti cancer treatments. (source)

In fact, here is a comprehensive list of the benefits of Focus vesiculosus and other seaweeds, with the appropriate reference source.

Benefits of Fucus Vesiculosus References
Rich source of health-promoting compounds: Fucoidans, Polyphenols, Fucoxanthin, Essential minerals [123]
Contains Fucoidans, bioactive compounds unique to brown algae, contributing to various pharmacological effects [4, 5]
Has antioxidant properties [1, 6, 7]
Anti-obesity effects [8]
Antidiabetic effects [1]
Anti-aging effects
Antimicrobial properties
Antitumor properties
[2, 9]
Anticoagulant effects
Anti-inflammatory effects
High Phlorotannins content, which are compounds from brown algae, with antioxidant, antibacterial, and antidiabetic properties [1, 5, 7
High mineral content [10]


Cautions When Using Seaweed

Although seaweed is perfectly safe for dogs to have, as with everything, there are some points to be aware of:

  • Excessive intake: The secret to a good healthy life from a nutrition perspective, is balance. Too much seaweed at once is not going to be good. Moderation is key. While all seaweed contains iodine, the safer upper limit for this is 170 mcg/kgAdhering to the dosing instructions is vital as the dosage recommendations on seaweed products will depend on the size of the dog. Specifically, studies have shown that these doses are usually at around 19mcg/kg of iodine on average, way below the safe upper limit.
  • Choking hazard: Seaweed, especially the dried kind, can pose a choking risk if your dog tries to swallow large pieces without properly chewing. Finely grounded powder is the best because you can sprinkle it and mix it with food
  • Quality of seaweed matters: Not all seaweed is created equal. Organic, non-farmed seaweed, harvested straight from the sea is the best in order to minimise the contaminants.
  • Contraindications: If your dog has a pre-existing thyroid condition, talk to your vet before introducing seaweed into their diet. Seaweed's high iodine content can interfere with thyroid function and medication.
  • Allergic reactions: Although rare, as with any new food, there is a risk of an allergic reaction. Watch your dog closely for any signs of an allergic reaction the first couple of times you are giving him any seaweed powder or treats. The same advice applies with the introduction of any new food or supplement. If you have any concerns, contact your vet and they can advise you further.

What Doesn’t work

Here are some of the ingredients or “superfoods” often promoted as helping dogs dental health, when in fact there is no proven benefit and may even cause harm or at least adverse side effects.


In humans, peppermint is widely known for freshening up the mouth and leaving a fresh minty taste after using it. Its flavour is commonly used in toothpaste and mouthwashes. However, although it is frequently consumed by humans, peppermint is actually pretty bad for dogs and should be avoided! (source)

peppermint leaves

It should not be ingested or even applied topically as it can irritate their skin. On the other hand, ingesting even small amounts of peppermint can lead to gastrointestinal upset, a runny tummy or stomach cramps. In more severe situations, it can even lead to vomiting and diarrhoea.

Therefore, peppermint will not help to freshen up your dog’s breath, or prevent bacteria build-up. It is actually more likely to cause adverse effects and cause your dog to have an upset tummy.


Turmeric is widely promoted as a great addition to dog food due to its antioxidant benefits, and in some cases it is even claimed to help “rub off” the plaque. This could not be further from the truth.

turmeric powder and roots

Firstly, the physical properties including its natural roughness will have zero effect on your dog’s dental health. As we have already seen, the only reason natural seaweed works on removing plaque, is because of its systemic effects, not the local ones.

Turmeric has so far not been found to have any systemic effects that would benefit your dog’s dental and oral health.

Of course, its antioxidants benefits have been scientifically proven, but the amount of turmeric needed would be far too high to include in your dog’s food. This is because turmeric, as you know, can have quite a punchy taste. Adding too much of it would put off most dogs from eating it.

The general consensus from vets is that turmeric present in any powders or food supplement for dogs, is in too low concentrations to have any antioxidant benefits">Even Purina agrees. 


I hope that I have managed to answer some of your questions with regards to what works and what doesn’t, in terms of dog teeth cleaning products. Just to summarise, Ascophyllum nodosum, a type of seaweed is of the utmost importance and it’s what most of the canine dental health studies have concentrated on. We know it works. As we have seen, there are compelling results in reducing plaque and tartar in dogs, although the exact mechanisms remain unclear.

Another type, Spirulina, enhances immune response and gut health in dogs, and Fucus vesiculosus or bladderwrack is rich in nutrients and has potentially anti-cancer properties.

I have also hopefully debunked some of the claims of benefits from peppermint and turmeric for dog dental health. Of most importance is for you to avoid products with peppermint, as this can be dangerous and nearing toxic effects in dogs.

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