What is Iodine Deficiency?
Iodine is a chemical needed by all living things for survival. It’s most important function is to provide a necessary component for thyroid hormones. Animals (and humans) have a gland in the base of the neck, the thyroid gland. This gland uses thyroid hormones to help regulate metabolic processes such as growth and energy expenditure. When thyroid hormones are imbalanced, certain disorders result.
Hypothyroidism is the most common hormonal disorder in dogs. It most commonly affects castrated male and spayed female dogs between the ages of 4 and 10 years across a variety of breeds. It develops when there is a deficiency of hormones thyroxine (T4) and tri-iodothyronine (T3).
Hyperthyroidism occurs when there is an excess of hormones produced by the thyroid gland. This is a very common endocrine disorder in middle age-older cats but is rarely seen in dogs.
Symptoms of hypothyroidism in dogs associated with low iodine levels include:
- Poor growth
- Hair loss
- Weight gain in older animals
- Behavioral changes such as irritability
- Lethargy, lack of interest in play, increased amounts of sleeping
- Weight gain (without an apparent increase in appetite) and obesity
- Cold intolerance – seeks out warm places to lie down, low body temperature
- Slow heart rate (bradycardia)
- Chronic skin disorders, such as dry skin, thinning of the hair coat
Symptoms of hypothyroidism in cats associated with low iodine levels include:
- Polydipsia (Excessive drinking)
- Polyuria (Excessive urination)
- Polyphagia (Excessive appetite)
- Weight loss
- Voluminous fatty feces
- Heat intolerance
- Skin lesions, dry, greasy, matted coat, alopecia
What Causes Iodine Deficiency?
The main cause of iodine deficiency is lack of iodine in the diet. Most commercial dog foods contain adequate levels of iodine, however, supplementation with green leafy vegetables is recommended.
At the North American Veterinary Conference 2005 Dr. P. Schenck showed studies which suggested that cats fed on a canned food were more at risk from hyperthyroidism (this may because of substances in the lining of the can or because of iodine levels). Switching brands of canned foods (including flavors in the same brand) can overwhelm the system and induce hyperthyroidism.
Diagnosing Iodine Deficiency
Proper diagnosis includes a thorough history, documentation of clinical signs, a thorough physical examination, and diagnostic tests to assess various organ functions, including:
- Complete blood count (CBC)
- Biochemical profile
- Thyroxine (T4) level, free-T4 level
- Canine TSH test
- Thoracic (chest) and abdominal radiographs (X-rays) in certain cases
Many other diseases of older cats can mimic the symptoms of hyperthyroidism (Diabetes mellitus and IBD).
Help for Iodine Deficiency
Fortunately, hypothyroidism is easily treated and involves the administration of daily doses of synthetic thyroxine. It is usually required for the rest of the dog’s life.
For cats, a Thyroidectomy may be required in more serious cases, and involves removal of the thyroid glands. This is a very effective procedure; however the operation itself may be risky because of the use of anesthetic with cardiac, renal, hepatic and gastrointestinal problems.
There are a number of natural ingredients – used in herbal and homeopathic remedies that have been shown to help balance thyroid hormones naturally. Fucus vesiculosisis is a prime source of iodine – crucial in supporting thyroid health.
Astragalus membranaceous is an herb that has been used as a revitalizing tonic for the endocrine system, while Eleutherococcus senticosis can be used to support healthy energy levels and endurance. Finally, Urtica urens is used to support healthy metabolism, thyroid and adrenal function. This herb is also a good source of minerals, as well as Vitamins A, B and C.
Tips related to Iodine Deficiency
- Dogs should receive 0.7 mg of iodine daily for every pound of dog food they eat (dry food).
- Don’t switch brands of cat food too regularly.
- Avoid food supplied in tins or cans.
- Cats should be given oily fish (sardines, pilchards) once in a while – to help boost iodine levels.
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