Ultimate Guide: Hyperthyroidism

The main forms of thyroid diseases are auto immune Thyroiditis (Hashimoto’s), Hypothyroidism (Non autoimmune), and Hyperthyroidism (Graves’ Disease).

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Graves’ Disease is an autoimmune disorder that causes hyperthyroidism. As with us humans, your dog’s thyroid gland is located at the front of the neck. It is part of the endocrine system, butterfly-shaped and consists of two lobes located either side of the windpipe (trachea) that controls metabolism. Metabolic processes are activities that occur in cells, involving the release of energy from nutrients your dog eats. Microscopically, thyroid tissue is made up of two types of cells: follicular cells and parafollicular cells. Most of the thyroid tissue consists of follicular cells. The follicles store and secrete iodine –containing hormones called thyroxine. Thyroxine (T4) and tri-iodothyronine(T3).

Thyroid hormones are important in the maintenance of normal, healthy activity levels of many different organs in the body: the heart, brain, liver, kidney and skin. All of which are vital for normal body function.

The thyroid requires iodine to produce the hormones. Iodine is an essential trace element absorbed in the small intestine, it is an integral part of T3 and T4. Sources of iodine include iodised table salt, seafood, seaweed, and vegetables. However, too much iodine can actually activate thyroiditis, so if you supplement, (kelp being one of the most popular for dogs), please use with caution.

Hyperthyroidism in dogs is a condition caused by the thyroid over producing thyroxine, increasing your dog’s metabolic rate to dangerous levels. It is much more common in older cats but when it does effect dogs it is usually serious. In some cases tumour growths in dogs can be benign and therefore easier to manage and may respond well to treatment, but malignant tumours can often spread to vital organs in the neck and risk further complication.

‘Hyper’ thyroidism (overactive) is rarer in dogs than ‘hypo’ thyroidism (underactive) and is usually a result from aggressive thyroid tumour called carcinoma (malignant) it begins in the epithelial tissue or the tissue that lines the gland.

Thyroid tumours are commonly seen in middle aged to older larger breed dogs such as boxers, beagles, golden retrievers, and Siberian huskies.

Hyperthyroidism can also be caused by an error in medications, which usually includes a synthetic form of thyroxine. An over correction of low thyroxine levels can sometimes result in hyperthyroidism. Graves’ disease in humans is often hereditary and between 25 and 50 percent of people have eye abnormalities, which are known as Graves’ ophthalmopathy. A small percentage of people with Grave’ disease develop a skin abnormality called pretibial myxoedema or Graves’ dermopathy.

The primary cause of this disease is due to the increased metabolism, the body goes into overdrive that has an impact on the overall function of the body. Most commonly, the condition results in weight loss, despite an increase in appetite.

Other possible signs and symptoms

  • Hyperactivity
  • Increased heart rate
  • Swelling of the throat – goitre
  • Anxiety
  • Excessive panting, heat intolerance
  • Increased thirst
  • Increased urination
  • Vomiting
  • Diarrhoea
  • Increased volume in stool
  • Irritability or aggression
  • Skin lesions, dry, greasy, matted coat
  • Heart murmurs
  • Congestive heart failure
  • Cardiomegaly (enlarged heart)
  • Dyspnoea (shortness of breath)

Unfortunately, the majority of these aren’t necessarily specific to thyroid disease and signs and symptoms can vary from case to case. A visit to the vets as soon as you notice any signs is the best option.

The checklist for thyroid disease

  • A fresh and unadulterated fresh food diet
  • Adrenal, liver, digestive immune and thyroid support
  • Omega fats and antioxidants
  • Vitamin deficiency test

Diet for thyroid disease

Fresh real food is advised for dogs with hyperthyroidism, preferably lightly cooked or raw. This is the most natural diet for dogs. Highly processed food is not recommended for dogs who have thyroid disease as they contain a very high percentage of carbohydrates, imbalanced omega 6-3 ratios and inappropriate ingredients, all of which cause inflammation in the body. They put huge pressure on the digestive system, pancreas and liver. Feeding whole fresh foods that provide a wide variety of nutrients will ensure a better chance of living a longer and healthier life.

Hyperthyroidism has been linked to pet foods (raw commercially prepared) that include the thyroid glands of slaughtered animals. Exogenous hyperthyroidism, a result of excessive intake of thyroid hormones is rarely recognised but is the only other recognised cause. If you are concerned, contact your raw food supplier and ask them what parts they are using or home prepare your own food to be sure – for example chicken necks or trachea.

Findings here Foods containing iodine should be avoided, some are listed here
  • Processed food containing grains, cereal and soy
  • Seafood
  • Dairy products
  • High amounts of poultry or beef
  • Egg yolks
  • Supplements such as kelp
  • Seaweed

Cruciferous Vegetables

such as broccoli, cauliflower, kale and brussels sprouts may stop the thyroid from using iodine properly.

Findings here

Veterinary approach to thyroid disease

‘Outdated or incomplete information taught in veterinary schools perpetuates inaccurate screening for canine thyroid disorder, since many vets are still applying outdated diagnostic methods. Tests used to determine thyroid disease include T4, free T4, T3, free T3, TgAA, T4AA, T3AA, and TSH their usage and importance depend on the situation of the dog being tested. T4 alone is not a reliable method’ – Dr Jean Dodds, DVM – The Canine Thyroid Epidemic 2011

Treatment depends on the underlying cause. Hyperthyroidism is often treated with antithyroid drugs, which stop the overproduction of thyroid hormone. Depending on the severity, treatment may entail partial removal of the tumour or removal of the entire thyroid gland. Chemotherapy or radioactive iodine (I-131) treatment or medications to counteract the excess hormone levels in which case the dog will be on replacement therapy for the rest of his life.

If left untreated the condition can cause heart and kidney failure. Therefore, the best approach to hyperthyroidism is to help prevent it by providing a wholesome natural diet and avoiding unnecessary chemicals or environmental hazards which are all possibilities that contribute to the disease. Listed here

  • Over vaccinating
  • Flea and tick preventatives
  • Unnecessary Steroids, antibiotics and NASAID’s
  • Food preservatives especially red dye found in processed food and treats

Protecting our dog’s immune system

Is key to thyroid health. Take a look at the wide array of toxic household products that may occupy your cupboards. Pesticides that you may apply to your lawn and the chemical flea and tick preventatives applied onto their skin and the overuse of vaccines. Our pets’ bodies are bombarded by threats to their immune systems on a regular basis, all of which play havoc and put a huge amount of pressure on major organs. By reducing or eliminating their exposure to as many reactive substances as you can, will help enormously.


Our dogs deal with stressful situations on a daily basis that are so different from where they evolved from. Stress can have a big impact on thyroid dysfunction so trying to modulate the stress response is always helpful as stress is an inflammatory process that can trigger autoimmunity in hyperthyroidism.

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The Liver

plays a key role in the chemical process that develops thyroid hormones; (TH) is required for normal development as well as metabolism.

Findings here

Nutraceuticals and herbs for hyperthyroidism

L- Carnitine; Is a natural supplement that can help treat the effects of hyperthyroidism. It is an amino acid derivative that naturally occurs in the body. Carnitine prevents thyroid hormones from entering certain cells. L-carnitine can reverse and prevent the symptoms of hyperthyroidism in humans, including heart palpitations, tremors and fatigue. It may also help manage Graves’ Disease without the support of anti-thyroid drugs.

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Selenium; Can help balance thyroid function. It is a micronutrient that the bodyrequires for the metabolism of thyroid hormones. A study showed that takingselenium supplements along with medical therapy for Hyperthyroidism for 6months had a positive effect on the response to medication.

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Moreover, Selenium is found to play a role in preventing thyroid disease.

Findings here.

Vitamin B complex; If your dog has hyperthyroidism it is possible, he may have vitamin B-12 deficiency and has poor methylation due to genetics or poor diet. An adequate supply of certain B vitamins is necessary for a healthy methylation cycle to occur. Folate (vitamin B9) B2 and B6 along with B-12 work synergistically for hyperthyroidism.

Magnesium; plays a key role in maintaining thyroid health. If the body doesn’t have enough magnesium, it can affect the ability to adsorb calcium. The inclusion of magnesium rich foods such as green leafy vegetables, nuts and seeds in the diet can greatly help to compensate for the deficit in the body.

Vitamin D and calcium; Calcium and vitamin D deficiencies are worth checking if there are signs of hyperthyroidism. Vitamin D deficiency has been found in thyroid cancer patients. These vitamins need to be optimised due to detrimental effects it has on the bones. Optimal replacement is necessary if deficiency is found as decreased bone mineral density can also lead to osteoporosis.

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Probiotics; leaky gut syndrome is a response within the gut that can cause inflammation to the ‘one cell epithelial’. Beneficial bacteria in the gut plays a key role in healthy thyroid function. We recommend a good soil-based probiotic.

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Optimising gut health is essential in thyroid function, 20% of thyroid hormone conversion occurs in the gut. We like to use soil bacteria and a positive correlation between Lactobacillaceae and Bifidobacterium spp has been found with selenium and zinc. As these bacteria are often diminished in Hashimoto thyroiditis and Grave´s disease, it has been suggested that gut composition and mineral regulation may have an impact on these diseases.

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Omega 3 fatty acids help reduce inflammation and supports immune system. They promote the thyroid to function normally that have anti-inflammatory, antioxidant and anti – fibrotic effects.

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Bugleweed; is a traditional anti-thyroid herb that works by reducing the output of thyroxine (T4) hormone and slowing down the conversion of T4 to tri-iodothyronine (T3).

‘It Is considered a specific symptomatic remedy for hyperthyroidism because it is known to slow thyroid function by reducing production of TSH. Its use, however, should be monitored by a holistic veterinarian’ – HerbalistsGregory L. Tilford & Mary L. Wulff.

Hawthorn; Berries are tiny red fruit that grow on trees and shrubs. They are known in herbal medicine for its ability to alleviate cardiovascular symptoms occurring in hyperthyroidism conditions and helpful for moderating an erratic heartbeat. They are loaded with antioxidants and anti-inflammatory properties.

Lemon balm; extracts of Lemon balm works on GABA levels. Gamma-Aminobutyric acid is an amino acid produced naturally in the brain. GABA functions as a neurotransmitter, facilitating communication among brain cells. GABA’s big role to play in the body is to reduce activity of neurons in the brain and central nervous system which in turn has a broad range of effects on the body and mind,including reduced stress, a more calm and balanced mood, alleviation of pain and aids sleep. Along with this, Lemon Balm works at ground level by detoxifying the body and strengthening the immune system to aid in hyperthyroidism.

Lastly, supporting detoxification with supplements such as methyl-B9, methyl-B12, magnesium taurate, NAC (N-Acetyl-Cysteine), milk thistle, and curcumin can raise glutathione, that is directly correlated to a healthy functioning thyroid gland.

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Prevention of hyperthyroidism is the best approach through proper diet and supplementation. For more info take a look at our consultation services. Thank you for taking the time to read.

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MPN Team x ‍

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