Kelp
Also known as: seaweed, ascophyllum nodosum
A brown seaweed that's the most bioavailable natural source of iodine — plus 60+ trace minerals.
What it actually is
Dried and ground seaweed, usually Ascophyllum nodosum harvested from the North Atlantic. Also studied for reducing plaque and tartar on teeth.
Why it's used in dog food
Provides iodine (needed for thyroid function), plus trace minerals hard to get from land-based food. Some formulations are specifically studied for reducing dental plaque.
A bit of history
Coastal peoples in Ireland, Scotland, Japan, and coastal First Nations have fed seaweed to livestock and dogs for centuries. The dental-plaque research came out of Europe in the 2010s.
Pros
- •Most bioavailable natural iodine source
- •60+ trace minerals in whole-food form
- •Specific kelp strains (Ascophyllum nodosum) reduce dental plaque with daily feeding
- •Tiny dose needed — a pinch per meal
Cons
- •Iodine overdose is possible — do not stack multiple kelp-containing products
- •Some kelp is contaminated with heavy metals depending on harvest waters
- •The dental benefit only works with the specific studied strain, not generic kelp
Safety notes
Do not exceed labelled dose. Dogs with diagnosed thyroid conditions should consult a vet before adding.
Sourcing & quality
Icelandic and Canadian Atlantic kelp are the cleanest. Look for third-party tested products.
Commonly found in
Skip this if…
Your dog has hyperthyroidism or is on thyroid medication.
The verdict
A legitimately useful whole-food supplement in small amounts.