How your diet can impact your thyroid health
Each year, there are approximately 60,000 new cases of thyroid disease reported in Australia, and women are more at risk.
We reached out to Clinical Naturopath and Nutritionist Melissa Briggs for her expertise. 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, and 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 a number of symptoms indicating some form of thyroid dysfunction. Many of these you may experience on a regular basis and perceive as ‘normal’, however you may be suffering from a thyroid condition if you notice a combination of these signs. According to Melissa, 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, selenium, zinc and omega 3 fatty acids are among the most important to incorporate into your diet. Melissa expands on each of these in more detail:
Iodine is a fundamental nutrient needed for thyroid hormone synthesis. Thyroid hormones T4 and T3 are composed of a tyrosine backbone with 4 or 3 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, its best to speak with your practitioner before increasing dietary iodine intake.
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 to 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 per 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 is 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 disease 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 (aka 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.
Melissa is a Clinical Naturopath & Nutritionist practicing 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.