Kelp has become a bit of a buzzword in the dog nutrition community. Some swear by this nutrient-dense natural supplement. Others warn that it can have harmful effects on dogs.
So, which is true? Well, as with most things “supplement,” it comes down to how you use it.
In this article, we’ll take a look at what kelp is, the proven benefits of supplementing with it, the evidence-based drawbacks, and how you can safely use kelp for your dog.
What Is Kelp?
The word kelp refers specifically to Laminaria and Fucus species of brown algae. These types of algae are also commonly known as seaweed, though there are a lot more types of seaweed out there than just kelp. All of these unique sea vegetables aren't plants or fungi but belong to the greater organism group known as protists.
Kelp grows in large underwater forests in cold, nutrient-rich waters throughout the world. These prolific sea plants can grow up to a foot per day and are vital to the underwater ecosystem.
The most common type of kelp harvested for human and animal consumption is Ascophyllum nodosum, a type of Fucus brown algae. Thousands of tons of this sea plant are wild-harvested every year. Most harvesting occurs in the oceans around New England, Canada, Iceland, and Northern Europe.
Is Kelp Safe for Dogs?
With so much kelp being harvested each year, it should come as no surprise that this ingredient makes it into a lot of different products. Humans consume quite a bit of kelp in the form of alginate, a common thickening agent added to dairy products and other foods. Many Asian dishes use kelp in whole form to add to the flavor and texture of dishes.
Kelp is also often added to commercial dry and canned dog food as a thickening agent. High-quality dehydrated, raw, and freeze-dried foods often use kelp powder to introduce trace minerals into their recipes.
Given how often kelp is used in both human and dog diets, it is safe to say that kelp is safe for dogs. However, how safe it is depends on how much your dog consumes. Their general health and the quality of the kelp supplement also play a notable role in how safe kelp supplementation truly is.
Nutritional Value
Sea plants, like kelp, are celebrated for their nutritional value, and for good reason. Unlike terrestrial plants that only have access to nutrients in the soil directly around them and those they can synthesize themselves, kelp has access to all the nutrients present in circulating seawater. They use their extensive fronds to collect these nutrients and store them in their cells.
They are incredibly powerful collectors of vitamins, minerals, and phytonutrients found in the nutrient-rich seawater they thrive in. Interestingly, the essential nutrients in kelp exist in very similar ratios to those found in the bloodstream of mammals.
Kelp contains all essential minerals that dogs require, including iodine and over 60 other trace minerals and vitamins. This sea plant is also high in antioxidants, amino acids, fatty acids, protein, and fiber.
Benefits of Kelp
The array of nutrients in kelp makes it especially helpful for supporting health and vitality. Research has found it's effective in treating specific conditions while helping to promote general health when used properly.
Helps Maintain Healthy Thyroid Function
Kelp supplementation is most often associated with thyroid health. This small gland in the neck requires iodine to produce hormones effectively. Too little iodine and the thyroid stops functioning properly, resulting in hypothyroidism and symptoms including goiters, poor coat health, weight gain, low energy, and constipation.
Allergies, skin issues, seizures, and obesity are also common issues in dogs with poorly functioning thyroids.
Because kelp is naturally high in iodine, it can help reverse iodine deficiency so that the thyroid can function properly. A significant number of dogs suffer from low thyroid function due to poor diets and the harmful effects of environmental pollution. Kelp can be a simple solution to support thyroid health in dogs with low-functioning thyroid due to malnutrition.
It is worth noting that the use of kelp in dogs with full-blown hypothyroidism can have more negative effects than positive. Additionally, feeding too much iodine can actually cause hypothyroidism in dogs. We’ll look at these drawbacks in more detail in the next section.
Supports Healthy Skin and Coat
Some of the first signs of hypothyroidism are a dry, brittle coat, flaky skin, and cracked nails. Not surprisingly, supplementing with kelp often improves these skin and coat issues. This is due both to the high iodine content of kelp and to the array of other minerals, amino acids, fatty acids, and antioxidants found in this product.
Fights Plaque
After thyroid health, the most common use for kelp in dogs is to help fight plaque. That’s because this seaweed contains a bacterium that releases an enzyme known to destroy the biofilm surrounding plaque.
Multiple studies have shown that when kelp is added to dog and cat food it results in lower plaque buildup on teeth over time. Because plaque contributes to the development of periodontal disease, kelp can be very helpful in maintaining canine oral health.
Supports Healthy Digestion
Kelp has also been found to help normalize digestion, reduce constipation, and improve the health of the dog's gut biome. It does this in multiple ways.
First off, kelp is high in fiber, but not just any fiber. Up to 75% of the dry mass of kelp is made up of alginate, a polysaccharide that acts as a natural laxative to help empty and cleanse the bowl. Alginate and other fibers in kelp also help to feed beneficial bacteria in the gut, which supports a healthy gut biome. Lastly, since digestive issues are a symptom of thyroid disorder, the iodine in kelp can help normalize thyroid function and reduce digestive symptoms.
Reduces Joint Pain and Inflammation
Kelp is packed full of flavonoids, bioactive compounds with anti-inflammatory and antioxidant properties. These compounds help to reduce inflammation throughout the body, including in the joints of dogs suffering from osteoarthritis.
Multiple dog studies have found a notable reduction in pain scores for dogs given a kelp supplement. Human studies have also found a significant link between the reduction of osteoarthritis symptoms and kelp extract supplementation.
Fights Certain Types of Cancer
After iodine, one of the most abundant minerals found in kelp is selenium. This specific type of selenium is highly bioavailable and easily absorbed and used by the body. In animal studies, kelp supplementation has been found to reduce the mammary carcinogenic effect of certain compounds. Because of this, it is widely believed that the low levels of mammary cancer in Japanese women may be attributed to their high kelp intake.
Adding kelp to the diet of intact, older female dogs may help reduce their risk of mammary cancer. Many naturopath vets also recommend kelp for dogs with lymphoma, thanks to its anticancer effects.
Drawbacks to Consider
Excess Iodine
Kelp is rich in iodine, which can be beneficial for dogs with iodine deficiencies but can be harmful if consumed in excess. Iodine is essential in small amounts, but too much can lead to thyroid issues, such as hyperthyroidism, and eventually hypothyroidism.
To avoid these issues, ensure your dog doesn't consume too much iodine from diet, supplements, or synthetic sources. Signs of iodine toxicity include excessive tearing, nasal discharge, drooling, and dry, flaky skin. Gastrointestinal symptoms like nausea, vomiting, and diarrhea may occur if a dog consumes too much kelp at once, primarily due to its high fiber content.
Potential for Allergic Reactions
Dogs can develop allergies to kelp, although it's rare. Watch for signs like itchy skin, rashes, hives, or digestive issues when starting or using kelp supplements. If symptoms improve after stopping the supplement, your dog may be allergic to kelp.
Use Caution with Sick Dogs
Dogs with kidney or liver issues should avoid excessive kelp due to its high potassium content. Dogs with hypothyroidism should only use kelp after consulting a vet, as iodine supplementation can affect their medication and may not be beneficial if thyroid damage is irreversible.
When Should You Supplement with Kelp?
Kelp can be very beneficial for treating specific issues such as low thyroid function, osteoarthritis, and poor dental health. In otherwise healthy dogs, adding a little kelp to their food twice a week is generally safe and a good way to provide trace nutrients.
Dosing
The dosing for kelp very much depends on why you are using it.
If you're giving your dog kelp to help with their teeth, we recommend getting a supplement specific for that reason and following the product dosing instructions. For osteoarthritis and low thyroid function, we recommend talking to a naturopathic vet to find the correct dose for your dog’s size and needs.
For dogs on homemade diets, kelp should make up about 0.25% of the dry matter they consume each day (assuming no other iodine supplements or high-iodine foods are being fed). Given how tiny this amount is, it can be very difficult to calculate. Following quality, well-researched homemade dog food recipes can take the guesswork out of the process.
In general, small dogs should receive about 100 mcg of iodine per day. For medium dogs, the recommended dose is 300 mcg, and for large dogs, it’s 500 mcg. In order to determine how much kelp to give your dog, you first need to determine how much iodine is in each serving, then adjust the serving based on the recommendations above. If your dog gets commercial dog food, be sure to also take into account the amount of iodine they already get in their diet.[1]
Best Kelp Supplements for Dogs
When it comes to the best kelp supplement for dogs, we recommend looking for a high-quality product above all else.
High-quality kelp supplements are transparent about where and how their kelp is harvested. The USDA certifies kelp as organic as long as it is harvested from water that is not overly contaminated with pesticides or herbicides and so long as the kelp is collected sustainably. Kelp harvested from coasts around the US, Canada, Iceland, and the EU is generally considered safer than kelp harvested from the coasts of China and other highly industrial areas.
Another aspect to look at when searching for a quality supplement is the amount of iodine present. Our dosing guidelines above assume an iodine concentration of around 750 ppm. But this number naturally varies for kelp and can be as low as 50 ppm and as high as 7,500 ppm. Depending on how much iodine your kelp supplement contains, you may need more or much less than the average recommended amount.
Ascophyllum nodosum tends to have less iodine, but this amount can still vary greatly between 300 and 1,200 ppm. Laminaria Digitata, a deep-water kelp, can have up to 7,500 ppm of iodine. Which one is better for your dog will depend on their size and needs.[2]
Our CHIRP Superfood Topper contains high-quality, organic kelp powder that is harvested in protected waters of Iceland. The topping provides a safe daily dose of iodine of about 200 mcg/serving for medium sized dogs on homemade diets as well as those that already receive some iodine in their commercial feed.
The Final Word on Kelp for Dogs
When it comes to using kelp as a health supplement for your dog, there is no one-size-fits-all approach.
For dogs on a homemade diet, kelp is often a necessary supplement to ensure proper nutrition. It can also be very beneficial for dogs with low thyroid function, osteoarthritis, and plaque problems. However, kelp and other high-iodine foods should always be used with caution, especially in dogs that have already been diagnosed with thyroid problems.
We recommend using kelp as an occasional supplement to support overall health or as part of a daily supplement that includes small amounts of kelp along with other high-quality, health-supporting ingredients, such as what you’ll find in our CHIRP Superfood Topper.
Sources
5027: The use of kelp in organic livestock | Agricultural Marketing Service. (n.d.). USDA.
Algae – Organisms for Imminent biotechnology. (2016). In InTech eBooks.
Myers, S. P., O’Connor, J., Fitton, J. H., Brooks, L. O., Rolfe, M., Connellan, P. A., Wohlmuth, H., Cheras, P. A., & Morris, C. A. (2010). A combined phase I and II open label study on the effects of a seaweed extract nutrient complex on osteoarthritis. Biologics, 33.
User, S. (2018, November 25). Immune Nutritional Management – Alaskan Malamute Health.
Wof, B., & Lewter, M. (2017). Seaweeds for animal health. IVC.
Sara Seitz worked in the pet industry for over a decade. In addition to being a certified dog trainer, Sara gained experience working as the general manager of a dog daycare and boarding facility, as the creator and manager of a pet sitting company, as a groomer, and as a dog behavior evaluator. She also has a bachelors in animal behavior from CSU. Currently, Sara works as a freelance writer specializing in blog, article and content writing.
