Iodine for Dogs: Iodised Salt, Kelp vs Wakame, and the Bigger Question

How dogs get iodine, why many homemade diets use iodised salt, and why wakame is gaining popularity over kelp as a whole-food source of iodine.

If you’ve followed my work for any length of time, you’ll know that I’ve always favoured whole foods over processed, synthetic or fortified ingredients whenever possible.

So while it’s no surprise to see commercial dog foods contain added salt, something I recently saw caught my attention. I was watching a canine nutritionist demonstrate how to formulate a balanced fresh-food diet for dogs at home, and he specifically recommended using iodised salt instead of sea salt. That single recommendation sent me down a rabbit hole.

At first glance, that seems a little strange. After all, most of us don’t think of iodised salt as a health food. But the reason many nutritionists add iodised salt usually has very little to do with sodium and almost everything to do with providing dogs with iodine — which they absolutely need.

I found myself wondering why we were reaching for a fortified ingredient rather than a whole-food source of iodine in the first place. While most conversations focus on how much iodine a dog needs, very few people seem to ask a much bigger question:

Should iodine come from a fortified ingredient such as iodised salt, or from whole foods that naturally contain it?

Interestingly, those questions extend far beyond iodine. In many ways, they get to the heart of how we think about nutrition itself.

Why Dogs Need Iodine

Despite being required in only very small amounts, iodine plays an incredibly important role in the canine body. Without it, the thyroid cannot properly produce the hormones that help regulate metabolism, growth, body temperature, energy production and countless other processes that keep the body functioning as it should.

According to nutritional standards such as AAFCO and FEDIAF, which are informed by foundational research including the National Research Council (NRC) Nutrient Requirements of Dogs and Cats, a dog’s iodine requirement is relatively small, measured in milligrams rather than grams, yet its impact on health is profound.

Like so many nutrients, iodine deficiency and excess can both create problems, which is why balance matters.

A Nutrient Isn’t Necessarily a Food

One of the recurring themes you’ll notice throughout my writing is the idea that an isolated nutrient isn’t necessarily the same thing as a food. Modern nutrition has become incredibly good at identifying individual nutrients. We can measure them, isolate them, add them, remove them and formulate diets around them. Yet sometimes I wonder whether we become so focused on individual nutrients that we lose sight of the food itself.

After all, when we look at a blueberry, do we really see a blueberry anymore, or do we see anthocyanins? When we look at an egg, do we see an egg, or do we see protein and choline? When we look at fish, do we see a food, or do we see omega-3 fats? The more time I’ve spent learning about nutrition, the more I’ve realised how often we reduce foods into their individual components and then assume we’ve fully explained them.

The reality is that foods are often far more complex than the nutrients we can currently measure. A food isn’t just a collection of vitamins and minerals. It’s a complex structure containing thousands of naturally occurring compounds interacting with one another in ways we are still trying to understand. That’s one of the reasons I believe a healthy dose of humility is important in nutrition. We have learned an extraordinary amount, but there is still an extraordinary amount left to learn.

Identifying a nutrient is important. Understanding how that nutrient behaves within a food and within a living body is an entirely different challenge. That’s why I don’t think the conversation should end once we’ve identified a nutrient.

Why Iodised Salt Exists

What we commonly call table salt usually begins life as a naturally occurring salt harvested from the ocean, salt lakes or underground deposits. By the time it reaches our supermarket shelves, however, it has often been heavily refined until it consists almost entirely of sodium chloride, with many of the naturally occurring trace minerals removed.

To be clear, both natural sea salt and refined table salt are predominantly sodium chloride. The difference isn’t that one contains sodium chloride and the other doesn’t. The difference is that less refined salts typically retain a broader range of naturally occurring minerals and trace elements, whereas refined table salt is intentionally processed to become a much more purified product.

Iodised salt is simply refined table salt with iodine added back in. This process is known as fortification, which is really just a fancy way of saying that nutrients are added to a food, often to address a known deficiency or to replace nutrients that may have been lost during processing. In the case of iodised salt, the iodine is typically added in the form of compounds such as potassium iodide or potassium iodate.

Now to be completely fair, iodised salt helps to prevent iodine deficiency, and that’s precisely why it was developed. Another reason many nutritionists favour it is that it provides a relatively predictable and measurable source of iodine. Unlike seaweeds, where iodine levels can vary considerably depending on the species, harvest location and growing conditions, iodised salt allows formulators to estimate iodine intake with a much greater degree of precision. From a formulation perspective, that consistency can be extremely useful, particularly when trying to meet established nutritional targets.

There are also practical considerations that rarely get discussed. Cost, availability and convenience matter. Iodised salt is inexpensive, widely available and highly consistent, making it an attractive option for both commercial formulators and people preparing homemade diets. Sea vegetables such as kelp and wakame may offer different nutritional packages, but they are often considerably more expensive, can be harder to source, and may vary more from batch to batch. Depending on the source, certification and quantity purchased, seaweeds can cost tens or even hundreds of times more per kilogram than iodised salt. In the real world, nutritionists, formulators and manufacturers are often balancing practical constraints alongside nutritional ideals.

With all that in mind, I have always found it curious that we can remove nutrients from foods, add a single nutrient back in, and then sometimes behave as though we’ve recreated the original food. Maybe we’ve solved the deficiency problem, but have we solved the entire nutrition problem?

The Difference Between Nutrients and Foods

This is where I think the conversation becomes genuinely interesting. Whole foods do not just provide isolated nutrients. They provide minerals, trace minerals, phytonutrients, naturally occurring compounds and what scientists often refer to as a food matrix. We are still learning how these compounds interact with one another and how they influence biological processes within the body. In many respects, nutrition remains far more complex than simply ticking off nutrient requirements.

The Difference Between Intake and Absorption

One of the themes I’ve returned to repeatedly over the years is that the amount of a nutrient present in a food isn’t necessarily the same as the amount the body ultimately absorbs and utilises.

I was discussing this recently with Billy Hoekman who is the Senior Vice President of Nutrition & Formulation at Green Juju, and we found ourselves talking about sea vegetables. On paper, some seaweeds can appear to contain enormous amounts of iodine. But as Billy pointed out, nutrition is rarely that straightforward. The body doesn’t interact with isolated numbers on a spreadsheet. It interacts with foods. As Billy explained, it’s something he thinks about constantly when formulating diets and food products.

Whole-food sources of iodine exist within a complex food matrix alongside countless other minerals, trace minerals and naturally occurring compounds. How much iodine is ultimately available to the body may be influenced by the source itself, how it was processed, the foods surrounding it and the broader diet in which it is consumed.

Research in humans and animal models suggests iodine from seaweeds can be less bioavailable than iodine from potassium iodide, and the percentage absorbed appears to vary widely depending on the seaweed species, processing method and surrounding food matrix. That means it would be too simplistic to assume every milligram listed on a spreadsheet behaves the same way in the body.

This may help explain why some populations consume seaweed-rich diets that appear to provide very large amounts of iodine when analysed in a laboratory, yet don’t necessarily experience the outcomes that might be predicted by looking at iodine intake alone.

To me, it’s another reminder that nutrition isn’t simply about counting nutrients. Labels, spreadsheets and formulation software can tell us what is present in a food, but a diet that appears balanced on paper isn’t always the same thing as optimal nutrition. Understanding what the body actually does with that food is an entirely different challenge, and that’s one of the reasons I’ve always been more interested in foods than nutrients. You can learn more about those topics here:

How Nature Delivers Nutrients

One of the things I find fascinating is that nature rarely delivers nutrients in isolation. Apart from the occasional example of an animal seeking out a mineral lick, nutrients generally move through food chains, ecosystems and entire environments before eventually ending up in a animal's stomach.

Wild dogs and wolves weren’t wandering around carrying nutrient charts or sprinkling iodised salt on their dinner. They obtained nutrients through prey, organs, blood, glandular tissues and the animals they consumed. Those animals, in turn, obtained nutrients from plants, soils and the environments they lived in.

In some coastal ecosystems, wolves have even been observed eating salmon and other marine foods, effectively drawing nutrients directly from the ocean. Scientists have even described marine nutrients moving from the ocean into forest ecosystems through spawning salmon. As bears, wolves and other animals catch salmon and carry them into surrounding forests, those nutrients become incorporated into soils, plants and the wider food web.

One of my favourite examples of how animals seek nutrients in unexpected ways comes from moose. Most people picture them browsing leaves and shrubs along the forest edge, yet moose have been documented diving several metres underwater to feed on aquatic plants. In some observations, they have descended to depths of around 5–6 metres (16–20 feet), remaining submerged while foraging. While this behaviour is primarily documented in lakes and freshwater environments rather than the ocean itself, it serves as a fascinating reminder that animals will often go to remarkable lengths to obtain the foods, minerals and nutrients they need. Nature is often far more resourceful than we give it credit for.

The Benefits and Risks of Turning Food Into Pharmaceutical Medicines

The above isn't an argument against isolated nutrients, extracts or medicines. In fact, many modern pharmaceuticals trace their origins back to plants, fungi and other natural sources. But one of the reasons medicines can be so powerful is that we've often taken a naturally occurring compound, isolated it, purified it and concentrated it to levels that may never naturally occur within a normal diet.

And that's often where both the benefits and the side effects come from. A compound that exists in relatively small amounts within a whole food can behave very differently when it is extracted, concentrated and delivered in isolation. Sometimes that can be incredibly useful. Sometimes it can create unintended consequences. Often it can do both.

We've seen this principle play out repeatedly throughout nutrition and medicine. In recent years, for example, concerns have even emerged around certain highly concentrated herbal extracts that were being consumed in amounts far beyond what a person would typically obtain from the original food itself.

To me, that doesn't suggest whole foods are automatically good and isolated compounds are automatically bad. Nutrition is rarely that simple. What it does suggest is that foods possess a level of complexity that can be difficult to replicate once we start pulling them apart.

Perhaps that's why I keep coming back to the same idea: a nutrient isn't necessarily the same thing as a food.

The body doesn't just consume nutrients. It consumes foods, meals and dietary patterns. And I believe that reality deserves far more attention than it currently receives.

If you’re looking at whole-food sources of iodine, another question naturally follows:

Kelp vs Wakame: Which one is the better choice?

Some of the richest natural sources of iodine include seafood and seaweeds such as kelp, nori, dulse and wakame, but if I had to choose a favourite, it would be wakame.

Part of my enthusiasm for wakame comes from the fact that it isn’t simply an iodine source. Alongside iodine, it contains a broad spectrum of minerals and trace minerals, as well as naturally occurring compounds such as fucoxanthin and fucoidan. Fucoidan in particular has attracted considerable scientific interest and continues to be studied for its potential biological effects and possible applications in areas such as cancer research. Whether future research confirms all of that potential remains to be seen, but I find it intriguing that a humble sea vegetable can attract so much scientific attention.

What really surprised me when I first started looking into seaweeds in late 2010 was just how concentrated they can be. A dog’s iodine requirement is relatively small, yet depending on the source, a single teaspoon of wakame powder can contain a substantial amount of iodine.

At first glance, that might not sound like much. But when you consider how little iodine a dog actually requires, it starts to put the concentration of some seaweeds into perspective, especially when presented in powder form, and why it’s important to view seaweeds as foods first and iodine sources second. Concentration still matters, which is why thoughtful sourcing and appropriate feeding amounts remain important.

With that said, I generally prefer wakame over kelp because kelp’s greatest strength can also be one of its challenges.

Kelp is often regarded as the heavyweight champion of iodine, and it’s easy to see why. Some kelp species contain exceptionally high levels of it. Personally, however, I think wakame strikes a more appealing balance for regular feeding. It still provides meaningful amounts of iodine while also contributing a broad range of minerals, trace minerals and naturally occurring compounds.

If kelp is the heavyweight champion of iodine, I see wakame as the more balanced all-rounder.

It also highlights why testing matters. Two seaweed products can look almost identical and yet contain dramatically different amounts of iodine depending on where they were harvested, the species involved and the conditions under which they grew. This is one of the reasons I am cautious about people blindly adding large amounts of seaweed powders to homemade diets without understanding what they are actually providing. Even when bioavailability varies, the amount of iodine present can still be significant, particularly when seaweed is fed regularly or combined with other dietary sources of iodine.

The Overlooked Sources of Iodine

Over the past decade, seaweed-based dental powders, dental chews and plaque-control supplements have become increasingly popular. Some of these products may genuinely help reduce plaque and tartar accumulation, which is one of the reasons they have developed such a loyal following.

What many people don’t realise, however, is that if a product contains kelp or other seaweeds, it may also be contributing iodine to the diet every single day. Equally, iodine may be coming from other added sources within the diet, including fortified ingredients and vitamin and mineral premixes.

A person might be carefully calculating iodine in a homemade diet while overlooking a daily dental supplement. Another might be feeding a commercial food that already contains iodine while also adding a seaweed-based plaque product to their daily feeding regimen.

Another thing to consider is that virtually all "complete and balanced" commercial pet foods already contain added sources of iodine. But that iodine isn't always listed as "iodised salt." In other words, many dogs may already be receiving iodine before any additional supplements are added.

Sometimes it appears as either potassium iodide, potassium iodate or calcium iodate. Sometimes it's included within a vitamin and mineral premix. And sometimes it can come from ingredients such as kelp or other seaweed-derived ingredients.

Why We Use Wakame in Augustine’s SuperBoost

People have asked me over the years why I chose wakame as one of the ingredients in Augustine’s SuperBoost rather than kelp, and the answer is actually very simple. Apart from my younger ego wanting to be different for the sake of being original, I wasn’t looking for iodine alone. I was looking for a whole-food ingredient that contributed to the bigger nutritional picture.

When I first started developing Augustine’s SuperFood, the precursor to many of the ideas that would later find their way into Augustine’s SuperBoost, I wasn’t sitting around asking myself how many nutrients we could cram into a formula. I was asking a different question altogether. Which foods consistently stand out as being genuinely powerful from a nutritional perspective? Which foods have stood the test of time? Which foods seem to offer more than meets the eye?

The more I looked into wakame, the more boxes it seemed to tick. It wasn’t simply a source of iodine. It contained a broad spectrum of minerals, trace minerals and naturally occurring compounds. It had a long history of traditional use in parts of Asia. It was nutrient-dense, and aligned beautifully with the philosophy that has guided Augustine Approved from the very beginning.

That philosophy has always been fairly simple. Start with real foods. Respect the complexity of nature. Avoid reducing nutrition to a handful of isolated compounds whenever possible.

That same philosophy is also one of the reasons we make wakame powder available as a standalone ingredient, whether you’re purchasing it under our canine label or our human label for everyday cooking. The product itself is exactly the same in both instances — the only difference is the label and its intended use. In both cases, the wakame is ACO and USDA Certified Organic, providing a simple whole-food ingredient that can be incorporated according to individual preferences and requirements.

Over the years I’ve spoken with countless people, raw feeders, fresh-food advocates and canine nutritionists who prefer to formulate or customise their own diets rather than rely entirely on commercial foods or supplements. Those people aren’t necessarily looking for a finished product. Sometimes they’re simply looking for high-quality ingredients that allow them to build and balance recipes themselves.

Wakame has become one of those ingredients because it naturally contains iodine alongside a broad spectrum of minerals, trace minerals and naturally occurring compounds. For people formulating homemade dog food and looking to provide iodine from a whole-food source, it can be a useful ingredient when used thoughtfully. Of course, as with any nutrient-dense ingredient, balance still matters.

The Bigger Question

At the end of the day, this article isn’t really about iodised salt, kelp or wakame. It’s about how we think about nutrition. Iodised salt may help prevent iodine deficiency, and that is exactly why it was created.

But perhaps the better question isn’t:

“How do we add iodine back in?”

Perhaps the better question is:

“What did we lose when we took it out in the first place?”

That’s a question I’ve found myself returning to more and more over the years. The more I learn about nutrition, the less interested I become in finding magic nutrients and the more interested I become in understanding foods.

For me personally, if I can provide a nutrient through a thoughtfully selected whole food, that’s usually where I’ll start, because whole foods often bring far more to the table than the single nutrient we’re measuring. And perhaps that’s something worth thinking about the next time you’re filling your dog’s bowl.

Frequently Asked Questions

Why do dogs need iodine?

Dogs require iodine for normal thyroid function, metabolism, growth, energy production and the production of thyroid hormones that help regulate countless processes throughout the body.

Can dogs have too little or too much iodine?

Yes. While iodine is an essential nutrient, both deficiency and excess can create problems. Like many nutrients, balance matters.

Why do some canine nutritionists add iodised salt to homemade dog food?

In most cases, iodised salt is added as a source of iodine rather than sodium. It is a simple way to help ensure homemade diets meet a dog’s iodine requirements. It also provides a relatively predictable and measurable amount of iodine, which can make formulating homemade diets easier and more precise.

Is iodised salt an effective source of iodine?

Yes. Iodised salt was specifically developed to help prevent iodine deficiency and remains an effective source of iodine when used appropriately.

What are natural whole-food sources of iodine for dogs?

Natural sources of iodine include seafood and sea vegetables such as kelp, nori, dulse and wakame, as well as other foods that naturally contain iodine.

Which is better: kelp or wakame?

Both kelp and wakame can provide iodine. However, wakame typically contains lower iodine concentrations than many kelp species while still providing a broad range of minerals, trace minerals and naturally occurring compounds. For that reason, I personally view wakame as a more practical option for long-term daily use.

Can seaweed-based dental supplements contribute iodine to a dog’s diet?

Yes. Many dental powders and plaque-control products contain kelp or other seaweeds, which means they may also contribute iodine to the diet. This is one reason it can be helpful to consider all sources of iodine, not just the main diet.

Do all seaweed products contain the same amount of iodine?

No. Iodine levels can vary dramatically between species of seaweed, harvesting locations and growing conditions. Testing and appropriate feeding amounts are important.

Does the amount of iodine in a food equal the amount the body absorbs?

Not necessarily. The amount of iodine present in a food is not always the same as the amount ultimately absorbed and utilised by the body. Factors such as the source of the iodine, the food matrix it is contained within, how the food was processed and the presence of other nutrients within the diet may all influence bioavailability. This is one reason nutrition is often more complex than simply looking at a number on a label or spreadsheet.

Is nutrition simply about preventing nutrient deficiencies?

In my view, no. Preventing deficiencies is important, but nutrition is also about understanding the foods that deliver those nutrients. Whole foods contain complex combinations of minerals, phytonutrients and naturally occurring compounds that may offer far more than any single isolated nutrient alone.

How did wild dogs and wolves obtain iodine before fortified foods existed?

Wild dogs and wolves likely obtained iodine and other minerals through prey animals, organs, blood, glandular tissues and the broader ecosystems in which they lived. In coastal environments, nutrients could also enter the food chain through marine foods such as fish and other seafood.

Scientific References

• AAFCO – Reading Pet Food Labels and Nutritional Adequacy Claims
• FEDIAF Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs
• National Research Council (NRC) – Nutrient Requirements of Dogs and Cats
• Seaweeds in the Oncology Arena: Anti-Cancer Potential of Fucoidan as a Drug—A Review
• Bioavailability of Iodine from a Meal Consisting of Sushi and Wakame Seaweed Salad
• Iodine Bioavailability and Accumulation of Arsenic and Cadmium in Rats Fed Sugar Kelp