Each year, there are approximately 60,000 new cases of thyroid disease reported in Australia, and women are 10 times more at risk than men. To help shed light on the topic, we reached out to BHSc Naturopath Melissa Briggs for her expertise on the topic. Melissa has personally overcome a form of thyroid cancer called a papillary carcinoma and now specialises in thyroid health and the role of nutrition.
What is the thyroid?
The thyroid is a small butterfly-shaped gland that sits at the front of the neck below the voice box. When functioning properly, its job is to uptake iodine from the diet to produce thyroid hormones, which are then transported throughout the body to be utilised by all cells and tissues. “Triiodothyronine, or T3, is the active thyroid hormone used by these cells and tissues and is responsible for regulating growth, body temperature, energy production, and metabolic and reproductive function,” says Melissa.
There are several different ways in which a thyroid disease may arise. Your thyroid is part of the endocrine system and controlled by the hypothalamus and pituitary glands to produce thyroid hormones. Hypothyroidism occurs when the thyroid produces an insufficient amount of hormones. Hyperthyroidism results when too much is produced. If there is immune involvement, low thyroid function is known as Hashimoto’s disease, and overactive thyroid function is Grave’s disease.
Signs of thyroid dysfunction
There are several symptoms indicating some form of thyroid dysfunction. Many of these you may experience regularly and perceive as “normal”, however, you may be suffering from a thyroid condition if you notice a combination of these signs. Common symptoms include:
- Severe fatigue
- Sudden or unexplained weight gain or loss
- Sensitivity to hot or cold temperatures
- Hair loss
- Digestive symptoms such as IBS, abdominal pain, bloating, gas, constipation or diarrhoea
- Poor appetite or never feeling satiated
- Goitre (a swelling in the neck caused by an enlarged thyroid gland)
- Dry, rough skin
- Anxiety and/or depression
- Heart palpitations
- Swelling of the eyes and/or face
- Memory loss
- Slow thinking and mental activity
- Irregular or heavy periods
- High cholesterol
Nutrients that support thyroid health
Nutrition plays an important role in thyroid health. “While eating a balanced wholefoods diet is optimal for thyroid health, there are a few key nutrients that stand out from the crowd,” says Melissa. Iodine, tyrosine, selenium, zinc and omega 3 fatty acids are among the most important to incorporate into your diet.
Iodine is a fundamental nutrient needed for thyroid hormone synthesis. Thyroid hormones T4 and T3 are composed of a tyrosine backbone with four or three iodine molecules attached. Being an essential trace mineral, the body cannot produce iodine itself and thus needs to obtain it from the diet.
While the thyroid has the highest concentration of iodine in the body, the breasts, ovaries and kidneys also require this nutrient.
Nutritional sources include: seafood such as fish and oysters, seaweed and eggs.
In cases of autoimmune thyroid disease, it’s best to speak with your practitioner to undergo urinary iodine testing before increasing dietary iodine intake as a sudden increase in iodine-replete individuals could contribute to a thyroid storm.
Tyrosine is a nonessential amino acid, meaning that the body can produce it from the conversion of phenylalanine inside the liver and kidneys. To produce tyrosine itself, the body needs optimal amounts of iron, a diet that’s high in phenylalanine and a healthy gut.
An imbalance in the gut microbiome can interfere with the phenylalanine pathway by inhibiting the phenylalanine hydroxylase enzyme needed to convert phenylalanine to tyrosine. This can result in a buildup of phenylalanine which, if not converting to tyrosine, can go down a more inflammatory pathway. This is why it’s important to ensure digestive health is optimal.
In the thyroid, tyrosine is combined with iodine to produce T4 (tyrosine backbone with four molecules of iodine), which goes on to be converted to active T3 when one molecule of iodine is removed.
Tyrosine also plays an important role in mood and sleep through its conversion in the brain to serotonin and melatonin.
Nutritional sources include: animal meats such as chicken, turkey and fish, along with avocado, banana, sesame and pumpkin seeds.
Selenium concentration is highest in the thyroid than in any other organ of the body, and, like iodine, selenium has an important role in thyroid hormone synthesis and metabolism.
Selenium is required for converting T4 to the active form of thyroid hormone T3, as it’s needed by the iodothyronine deiodinase enzyme responsible for this conversion. In conjunction with this, selenium is required for the recycling of iodine, the main building block of thyroid hormone. Because of the potent antioxidant quality of selenium, this nutrient contributes to antioxidant defence within the thyroid by removing oxygen-free radicals generated during the production of thyroid hormones.
Studies have shown that patients with autoimmune thyroiditis who undertook supplementation with 200mcg/day of selenium had a 40% decrease in thyroid antibodies antithyroid peroxidase (TPOAb) and antithyroglobulin (TgAb).
Nutritional sources include: brazil nuts, meats and some vegetables. In fact, 2 – 3 brazil nuts are enough to reach your daily requirement. But don’t go overboard – too much selenium can lead to toxicity.
While iodine and selenium are often considered the superstars of the thyroid nutrients, zinc is just as important. Just like selenium, zinc is required for the enzymes that convert T4 to active T3 and deficiency is linked with lower levels of thyrotropin-releasing hormone needed for the production of thyroid-stimulating hormone (TSH) by the anterior pituitary gland. This means low zinc levels can lead to reduced thyroid hormone, reduced hormone conversion and thus hypothyroid symptoms. In particular, hair loss can occur as zinc is needed for healthy hair growth.
Conversely, thyroid hormones are essential for the absorption of zinc, and hence hypothyroidism can result in acquired zinc deficiency.
Zinc is also needed for a healthy immune system. Low levels of zinc are associated with an increased risk of autoimmune diseases such as Hashimoto’s and Grave’s disease.
Nutritional sources include: nuts and seeds, oysters, legumes and meats.
Omega-3 fatty acids
Omega-3 fatty acids EPA and DHA have been shown to produce metabolic by-products called resolvins, which have been shown to not only reduce inflammation but also prevent it from starting. This is of particular importance when it comes to thyroid disorders, which arise from inflammation and destruction of the thyroid gland itself.
The thyroid also requires omega 3 along with omega 6 for the production of a substance called delta iodolactone, which is needed for apoptosis (programmed cell death). A deficiency in both omega 3 and delta iodolactone can result in goitre (nodule) formation where there is cell growth with no apoptosis.
Nutritional sources include: oily fish like salmon, mackerel, and sardines, flaxseed oil and nuts and seeds.
If you are experiencing some of the symptoms mentioned earlier in this article and are concerned about your thyroid health, our resident nutritionists are available to consult with you about how you can tailor your diet accordingly.
Melissa is a BHSc naturopath practising out of her clinic in Brisbane where she works with clients from all over Australia. After completing her bachelor’s degree in health science at Endeavour college of natural health, Melissa has focused her passion on hormonal health, including reproductive and thyroid disorders. She is now undergoing her Masters in advanced naturopathic medicine majoring in integrative women’s health through Southern Cross University.
If you would like to read more about Melissa’s history with her own thyroid health, click here.