Dried Kelp

Kelp is a large brown seaweed that is dried and ground for use in pet food. It contains natural iodine and many trace minerals. Cornell's Feline Health Center notes that the cause of feline hyperthyroidism is not known and lists dietary factors among possible contributors. If your cat has a thyroid or other medical condition, ask your veterinarian about iodine sources in its food.

Source: vet.cornell.edu

Kelp is added as a natural source of iodine and trace minerals. Iodine is needed to make thyroid hormones, as Cornell's Feline Health Center explains. Most cat foods also add iodine in a measured mineral form, so kelp is not the only source. The iodine level in seaweed can vary by species and harvest.

Source: vet.cornell.edu

No study has proven that kelp causes hyperthyroidism in cats. Cornell's Feline Health Center says the cause is not known and lists both deficiencies and excesses of certain dietary compounds as possible factors. A 2010 review in cats discussed how the wide range of iodine levels in commercial cat foods might relate to the disease, but it did not settle the question.

Source: pubmed.ncbi.nlm.nih.gov

Kelp names a specific group of large brown seaweeds, while seaweed meal is a broader term for dried, ground seaweed that may come from one or more species. Both are used for iodine and trace minerals. Pettings lists dried kelp and seaweed meal as separate ingredients and scores them the same way.

Pettings gives dried kelp 2 out of 5 and lists it as an herb or plant extract. It appears on 25 of the 149 dry cat foods we list. The page notes that iodine in seaweed varies and that a link to thyroid disease in older cats has not been proven. Each food's page shows how it scores overall.