Kelp for Dogs- the Good, the Bad, and the Mumbo Jumbo

January 5, 2017 at 1:12 am

Happy New Year to my friends and readers, I am looking forward to a great year ahead, after what many described as an Annus Horribilus  — 2016!  One of the comments I’ve received a lot, about this blog, in email and on my Facebook group, is that my entries are “amazingly informative” (blush) but sometimes a lot to take in, and that shorter, more frequent offerings would be appreciated. Ok, then – I can do that! Something that comes up a lot on my radar is this idea of “Superfoods” – and like many trendy, popular-nutrition concepts, Superfoods have both merit and drawbacks. Most of the popular trends you will read about, from turmeric to coconut oil to goat’s milk, are based on some really good, factual ideas – but then become sensationalized, in order to be more widely marketed, and sometimes to the point of nonsense.  This happens within the herbal world – as a clinical herbalist, of course I know that all the “Herbs of Commerce” are  wonderful, useful and important to know and work with – but they can all be misused – underdosed, used as panaceas when other herbs would have been preferable, given in a form that is not well absorbed, or a formulation that is not energetically balanced…they are great allies, but not panaceas. Most Herbs of Commerce – think Milk thistle, Slippery elm, Chamomile, Echinacea – offer applications well beyond that one condition they’re marketed for – and all have limitations when used in an allopathic fashion, in other words as a more natural replacement for a veterinary drug. My hope is that by taking a  well-rounded look at all of these foods and supplements, as well as my ongoing herbal monographs and articles, readers will grow more aware of the true range of options available to them,  and think of  both so-called Superfoods and Herbs of Commerce as  having pros and cons – thus offering a much wider spectrum of possibility when looking at support for all kinds of health challenges.

I’m going to be posting, over the winter, about bone broth, goat’s milk/kefir, coconut oil, turmeric, cinnamon, apple cider vinegar and more. I feel I can offer a little more insight and balance to the material already posted everywhere, about these helpful, but not panacaea, foods, herbs and supplements.


Today, after reading a recent post recommending that people give kelp to dogs just… across the board, claiming benefits for it that vastly exceed what  it actually offers, and omitting information about iodine content, thyroid health and more – I decided to start with kelp.

Adding kelp to the canine diet has been around for a while now. When I started my research in this work, back in the 90s, it was common to see kelp (along with flaxseed, Vitamin C and assorted other goodies not quite so popular these days) added to all home made diets, irrespective of the content of the recipes. More recently, astute home feeders have come to realize this is not the best practise, and I hear about adding kelp to kibble (a big no-no) much less frequently. But the idea still pops up here and there…so let’s take a look at the facts about adding kelp to a canine diet.
First;  please bear in mind, sites that list great litanies of amazing claims about ANY supplement really are questionable. Kelp doesn’t work as a panacea for a million health issues and it can actually create some, if unthinkingly added. What kelp will do, and yes I make use of it in many home made diets, is contribute iodine to the diet.
(Note that if you feed a quality commercial food, the iodine will be factored in already, so to add more can lead to hypothyroidism, which we will get to in a moment).

Now, what does iodine do, and what foods is it found in?
Iodine is a non-metallic trace element , which is essential in the diet for the health and correct function of the thyroid gland. Commercial foods will have added adequate levels to meet requirements, I’m saying it again – more is not better! Seafood is the best dietary source, and many foods we humans consume are supplemented with iodine, but these (milk, bread) are not regularly fed to dogs as part of their home made diet and basing a whole canine diet around seafood is not a good idea either.. So, home made diets can be quite low in iodine, and over time, this can contribute to the development of thyroid dysfunction.  HOWEVER – adding too much kelp can also  backfire badly and contribute to the development of hypothyroidism in dogs – yep, this is one of those nutrients we want to do our best to get just right, in the diet.  Here’s Dr. Jean Dodds, world renowned thyroid specialist, on the importance of correct iodine intake:

“….excessive iodine supplementation can result in the overproduction of the T4 and T3 in dogs and cats, which triggers unintended cascading effects: in dogs, the immune system may wind up attacking the thyroid gland (producing excessive amounts of thyroglobulin autoantibody) which end up suppressing thyroid levels and causing the very hypothyroidism it was meant to prevent; whereas in cats, the overdosing can result in overt hyperthyroidism.”


So, when home feeding a dog, how do we get it right? A dogs’ requirement for iodine is easy to calculate; by using the method described elsewhere on this blog, take the dog’s weight in kilograms to the power 0.75 and you will have what we think of as the Metabolic Weight. To find your dog’s iodine requirement, or more correctly his recommended Allowance, you multiply the Metabolic Weight by 29.6.

So, a quick example. My dog Danny weighs 85 pounds.
That’s 38.55 kgs.

Taken then to the power of 0.75, we get the number 15.47, which is his metabolic weight, or MW.
Multiply 15.47 by 29.6, we get 458 mcgs, which can be rounded up to between 460 and 500 mcgs – daily. That’s our goal, and we need to meet it on a consistent basis. The next step is to assess what’s actually in the food, so we don’t oversupplement.
Now, it’s not the easiest thing, to calculate the actual amount of iodine in the diet, mostly because most software/the USDA database don’t actually provide levels in foods. We have to use  a general idea of which foods contain how much (there’s a link at the bottom of this entry) and make a calculation. I’m going into this much more deeply in the E-booklet, but trust me when I say that most recipes come up low. Simply put, they need some iodine. And while not the only way to provide it – some sensitive dogs do better with non-kelp sources – many dogs do well with kelp added to bring the iodine up to desired levels. But – and here’s the rub – it’s not as simple as adding a “teaspoon of kelp for a medium dog and two teaspoons for larger ones” etc. There are a couple of things to take into consideration, and they are super important….you’ve stuck with me this far, so here’s the takeaway message.


If you use kelp to supplement iodine in the diet, which in my opinion is the ONLY reason to use it, make good and sure that the product you add identifies the actual iodine content of the capsules or loose powder, on the label. In putting this entry together I evaluated 16 products, and found a huge range of iodine content – from as low as 225 mcgs per capsule to as high as 780 (!) and many that were completely lacking in  nutritional information of any kind. If you are going to add kelp, you need to know the iodine content! This is foundational – and then, we have to consider the potential for seaweed in this day and age to be contaminated. Heavy metals in particular, can accumulate in sea weeds, so you need a pure source, or you are better off using iodine drops. I’ll be going into this in more detail in the Supplements E-booklet later this year.

Iodine must be supplied in the diet, whether cooked or raw, if you are making your own food. While kelp contains very, very small amounts of other vitamins and minerals, none are present in amounts high enough to make a meaningful contribution to a  diet (and it certainly doesn’t provide VitaminD3, as one site actually claimed)  And some, such as iron, are in a very poorly absorbed form (non-heme). Don’t rely on kelp for significant nutrient value outside of iodine, and make sure you get that one right. Note that kelp itself can promote itching in some dogs and you may need to work with a pure source of iodine, too.
Any questions? I’ll be happy to clarify. 🙂

Iodine content of some foods:



2 thoughts on “Kelp for Dogs- the Good, the Bad, and the Mumbo Jumbo

  1. This makes the assumption that all dogs regardless of breed, age or health have the nutritional requirements. Which they do not. I am curious of how you manage, measure and chart your “clinical” nutraceutical therapeutic advice? And if you ever share these clinical studies/results?

    • Hi Daryll – not sure how you came to the conclusion I’m saying all dogs have the same requirements – the actual requirements for all nutrients, Vitamin A to zinc, are based on MW (metabolic weight) and calculated individually. Macronutrient content can vary widely, whereas micronutrients – vitamins and minerals – are consistent according to metabolic weight. Growth requirements, of course are different. I work with the National Research Council’s Nutrient Requirements of Dogs, as my manual of information regarding the science of basic nutrition – and various other texts as well as clinical experience inform my therapeutic approach to nutritionally responsive illness.
      I hope that helps! Please don’t hesitate to ask anything that wasn’t clear. 🙂

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