Everything we assume we know about iodine in dogs is based on studies of conical flask iodine (iodide) and kibble-fed dogs. Like every other mineral (calcium, phosphorus, zinc, iron, magnesium, manganese, copper) the artificial, conical flask version is handled very differently by the body. For the aforementioned minerals, it’s because they are not chelated to a carbon molecule. This the body hates. Eg dogs absorb about 10% of the zinc or iron oxide fed to them, so they have to include LOTS in their mixes (and the AAFCO guidelines thus say to give LOTs, incorrectly – when you are using real food their “minimum” figures are excessive).
Iodine is different. Both conical flask iodine and food-sourced iodine is actually iodide (bound to something like potassium) as iodine on its own would actually kill you. But it turns out it’s the conical flask iodide that has the dramatic effect on the body because it’s not bound up with fibre which slows its delivery to the bloodstream.
Hence studies of dogs fed either kibble OR real food, when supplemented with conical flask iodide, develop thyroid issues.
However, in a “real” iodide study where dogs were fed a whopping 15g of Ascophyllum per 1kg of food fed to dogs (this is more than double the dose of our Canident where we say a 35kg dog eating 1kg a day would be eating 6-7g max). The authors fed this for a month and found the “dogs showed good health conditions throughout the study“.
We shouldn’t be too surprised at this. We know Japanese folk are happily ingesting up to 8-20 times their RDA of iodide from seaweed and fish each day, with no problems (and those RDAs are not based on conical flask data, we wouldn’t be so foolish in human nutrition…but then, Ronald Mc Donald doesn’t write our nutritional manuals, for the large part). If anything, the Japanese derive great benefit from the practice, being among the healthiest and longest-living people on the planet.
The most recent test of our beloved tooth-cleaning, brown seaweed-based product Canident during summer (when it is expected to have its highest iodine content) reveals it contains 340mg/kg or 0.34g of iodine per kg of product (dry weight). This means, at its height, Canident is providing around 25 times (and up to 50 times in summer at the max dose) of the dog’s RDA for iodide, according to the conical-flask data AAFCO enthuses (a group most of us know to ignore for nearly every other nutritional statement…).
So just to let our customers know, on the basis of the above and the fact we have never, ever heard of ill harm from consuming our products over the last decade, we will not be dropping the recommended feed amount on our label, until we know more.
On knowing more, we badly want to look into this – the thyroid impact on dogs fed a daily feed dose of seaweed. I’m chatting about this with a group. There is an issue here. You need to take bloods and that you are not allowed to do (outside of illness in the vets) as it falls under “experimentation”. The paperwork there is enormous, rightly (mind you, they can test dry food on 6 caged dogs for 6mths, is there anything crueler?!!).
So that’s where we are with the nutrient. It’s a tricky one and folk are very confused but I’m not going to shy away from the discussion. I see some manufacturers stating their iodine contents as incredibly low, I suspect to avoid having this discussion with their clients online. In many instances, including when looking at the figures stated by an industry leader, I’m not aware of any brown seaweeds that clean teeth have so little iodine, even in winter (unless it’s near a leaking nuclear power plant…I’m joking, of course…sort of).
I’m very open to discussion about this. If you have any ideas, I’m all ears. I want this answered as much as everyone else. Howeer, like most other conversations about correct or optimal nutrient inclusions for dogs, we are at sea (pardon the pun), lost in a melee of non-sensical dry food, George-Jetson-style nonsense.
For now, I’m going to see what info I can find on farm animals (pigs, chickens, cows, all get seaweed in great abundance…). I will keep you all posted what I find.