Iodine levels in cat food – either too low or too high
In a study of client-owned hyperthyroid cats, feeding iodine-restricted food (0.32 ppm on a dry matter basis) decreased total T4 concentration and improved clinical signs after consuming the diet for 4 weeks. No adverse effects associated with feeding the iodine-restricted diet were observed. Although dietary iodine restriction appears to be a valid option in the management of hyperthyroidism in a subset of hyperthyroid cats in which strict dietary compliance can be achieved, there is concern that many cats do not achieve total T4 values in the lower half of the reference interval, indicating optimal control of hyperthyroidism may be difficult via modification of diet alone.
My cat has an over-active, swollen thyroid, causing him to constantly be hungry, and frequent vomiting. So, out of four options - radiation treatment, surgery, daily tablets, or a changed diet - we chose to give him a changed diet, with no iodine which the thyroid needs to function apparently. However, the batch of non-iodine foods were usually not eaten by our cat, so instead a family member decided to give him 100% natural (packaged) meat food instead (which predictably were met with favour from our cat).
After starting on e medication, he seems more picky with his dry food choice though he loves his Wellness Core chicken wet food. Have been changing his dry food for the third time now & would like to know whether should I feed him high or low protein food? He has an elevated liver & kidney values since the last blood test on Friday before starting on the medication. Most commercial food contains higher Iodine (fish oil & kelp), phospohrous, sodium selenite, carrageenan and Iodize salt. Is it alright for his condition? Is there any recommendation on the food? Is Wellness, Natural Balance & Evo good enough?My 11-ish (don’t know for sure, she was a rescue) cat was just diagnosed with hyperthyroidism. It was amazing to me how radiative iodine therapy was pushed as the most favorable option, followed by the new Science Diet food (which I will not feed for a variety of reasons). At no point would my vet discuss with me anything I could do from a diet perspective to help the situation in addition to methamizole.With that being said, I'm still going to offer this choice to my clients with newly diagnosed hyperthyroid cats. I'll discuss all of their options and let them know that with pills or radio-iodine therapy I'm really comfortable with advising owners how to treat. While I recognize that feeding a special food is way more convenient than giving medication, I need to advise my clients that if they choose the food they're venturing into "experimental" territory.Dietary Treatment:
An iodine-restricted diet (Hill's Prescription Diet Y/D) is available commercially. Consumption of this diet by a hyperthyroid cat decreases production of thyroxine by the thyroid gland by limiting the amount of iodine necessary for thyroid hormone production. Cats must eat only this diet lifelong with no supplementation with other foods, treats, or hunting. Decreasing dietary iodine intake to 0.17 ppm (μg/kg) decreases serum total thyroxine (TT4) concentrations in cats with spontaneous hyperthyroidism. Restricting iodine content of the food to 0.28 ppm or less normalizes serum TT4 concentrations in a majority of hyperthyroid cats for up to 17 weeks. There are a limited number of studies assessing efficacy of an iodine‐restricted diet for treating spontaneous hyperthyroidism in cats. Veterinarians had recently begun managing feline hyperthyroidism with nutrition, using a pet food formally launched in October 2011, Hill’s Prescription Diet y/d Feline Thyroid Health. The food limits dietary iodine intake, and the staff was finding that in the majority of cats, thyroid levels returned to normal within three weeks of transitioning to the food.