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Hypothyroidism in dogs

Hypothyroidism in dogs

Cecilie Hemsen Berg

If your dog suddenly gains weight and lacks energy, it may be a sign of hypothyroidism. Hypothyroidism occurs when the thyroid gland does not produce enough thyroid hormones, which are important for metabolism, growth and development. If the thyroid malfunctions, nearly every system in the body can be affected. This condition is more common in medium to large breeds and is rare in toy breeds. The gland uses iodine from food to make thyroid hormones (T3 and T4).

Causes of hypothyroidism

Hypothyroidism is fairly common in dogs and the main cause is genetics. It affects all dogs, but Labrador retrievers, Doberman pinschers, Irish setters, Dachshunds, Boxers, and Cocker spaniels are more predisposed. In addition to this, spayed females tend to develop hypothyroidism more often than intact females. 

Hypothyroidism dog

Approximately 95% of cases of hypothyroidism in dogs are caused by either lymphocytic thyroiditis (the dog’s immune system attacks the thyroid) or idiopathic atrophy (thyroid tissue is replaced by fat). An unbalanced diet, environmental toxins (pesticides and herbicides), medication, liver or kidney disease and vaccinosis can also increase your dog’s risk of developing hypothyroidism. 

Symptoms of a slow thyroid

The symptoms are often diffuse and it shares symptoms with other conditions. The diagnostic testing may therefore be extensive in order to get a definitive diagnosis. If your dog is suffering from hypothyroidism you may notice one or more of the following symptoms:

Hypothyroidism dog
  • Abnormal behaviour (fear, anxiety, aggression, irritability)
  • Unexplained weight gain
  • Skin and coat issues (dry, scaly skin, thinning coat, dull-looking coat, hyperpigmentation, thickening of skin, recurring skin infections)
  • Lack of energy, lethargy, mental dullness
  • Lack of coordination
  • Eye disorders (dry eyes, corneal lipid deposits, corneal ulceration)
  • Slow heart rate, cardiomyopathy
  • Lameness
  • Reproductive issues
  • Cold intolerance

Treatment of hypothyroidism

Hypothyroidism is a chronic condition and treatment will therefore need to be lifelong. A dog with this condition will need a combination of a healthy diet and hormone replacement medication. It can take some time for your dog’s hormone levels to reach normal levels, and your vet will need to monitor how the treatment is progressing by taking regular blood samples.

Your dog has to be on medication for the rest of its life in order to manage the condition. In addition to this, dogs with hypothyroidism need to eat an appropriate diet that includes balanced levels of protein, iodine, vitamins, minerals, probiotics, antioxidants, fats and complex carbohydrates. 

Hypothyroidism dog

The gland utilises iodine from food to create thyroid hormones, hence why this mineral is so important. Iodine supplementation can be tricky as you can easily give your dog too much, negatively affecting your dog’s thyroid. It is therefore recommended that you always consult with a veterinarian to find the best treatment for your dog. 

Food for hypothyroidism

When it comes to nutrition and supplements, any dietary change or supplementation must be discussed with your veterinarian. Dogs with hypothyroidism need food with lean, easily digestible proteins, low-fat content, a balanced source of complex carbohydrates, omega-3 fatty acids, selenium, zinc, iodine and probiotics in addition to all the other vitamins and minerals dogs need. Iodine is essential for normal thyroid function, but iodine supplements can be difficult to dose correctly, and too much can have a negative effect with regard to the medication. 

There are some foods that can help support healthy thyroid functioning. The following vegetables in small amounts and steamed/cooked may help: green beans, carrots, celery, asparagus mushrooms, pumpkin, and spinach. Sprouted sunflower seeds can also be added to the food from time to time. Sunflower seeds are high in selenium, which is important for the thyroid gland. Seaweed/sea lettuce contains iodine, which is beneficial for the thyroid gland in balanced amounts.

If your dog is not allergic or sensitive to fish, you can add some white fish like cod or hake to their food. It provides lean, complete protein and omega 3 – which has a mild anti-inflammatory effect. Always be sure to check with your veterinarian before adding new foods to your dog’s diet. 

Hypothyroidism dog

Research suggests that it is advisable to limit the intake of vegetables such as broccoli, cabbage, cauliflower, Brussels sprouts and kale, especially in cases where the dog has an iodine deficiency. These vegetables contain goitrogens* that can block the thyroid’s ability to use iodine. These are generally healthy vegetables for dogs, and by steaming them we reduce the content of goitrogens. Foods with high concentrations of soy which contain isoflavones can interfere with the absorption of iodine in the thyroid gland. Fat inhibits the production of thyroid hormones, and can also interfere with the body’s ability to absorb the medication.

* “goitros” is the Latin name for goitre, which means enlargement of the thyroid gland.

Nala Health Senior and LITE food contains 22% protein from black soldier fly larvae which is a complete, clean and easily digestible protein. The fat content is 10% and comes from black soldier fly larvae, cold-pressed canola oil and coconut oil. We use sorghum, millet and oats, which are gluten-free and provide fibre, minerals and energy. The food does not contain soy, wheat, maize or barley. 

Our food has a balanced antioxidant, vitamin and mineral profile, including iodine, zinc and selenium which are important minerals for the thyroid gland. We use marine algae/sea lettuce which is a good source of DHA omega 3 and iodine. Peas, carrots, sweet potatoes, baobab fruit, rooibos and alfalfa provide antioxidants and fibre. Chicory root, butyrate and probiotics support gut health.