Find out how a little gland can have big effects as Alessandra Felice feeds your thyroid knowledge.
The thyroid gland is a small, butterfly-shaped endocrine gland located in the base of the neck, just below the Adam’s apple. Its main function is to create thyroid hormones, T4 and T3. T4 and T3 are then released into the blood and are transported throughout the body, where they control metabolism, the conversion of oxygen and calories to energy.
Every cell depends upon thyroid hormones for regulation of their metabolism. In fact, every cell in the body has receptors for thyroid hormones and these hormones impact all major systems directly, acting on the brain, the gastrointestinal tract, the cardiovascular system, bone and red blood cell metabolism, gall bladder and liver function, steroid hormone production, glucose, lipids, cholesterol and proteins metabolism, as well as body temperature regulation. It’s a control centre for your entire body.
The thyroid gland is part of a network of communication called the hypothalamic-pituitary-thyroid axis (HPT axis), which also include the hypothalamus and the pituitary gland. The pituitary gland reads and responds to the amounts of T4 circulating in the blood, but it also responds to the hypothalamus, which is a section of the brain that releases the hormone TRH (thyrotropin-releasing hormone). TRH stimulates TSH (thyroid-stimulating hormone) release in the pituitary gland that gets released to promote thyroid hormone production.
Know hypo from hyper
Normally, the thyroid releases just the right amount of hormone and TSH levels can remain pretty constant, responding to changes in T4 levels and vice versa. But there are some cases where this mechanism doesn’t function at its best causing the development of certain thyroid conditions. The two that are most commonly observed are hypothyroidism and hyperthyroidism.
Hyperthyroidism occurs when an excess of thyroid hormones over-stimulates the body’s metabolism, resulting in increased heart rate, anxious states and often weight loss. While hypothyroidism, a decrease or lack of thyroid hormones, slows down the body’s metabolism and can cause sluggishness, fatigue, weight gain, depressive states and heart complications in extreme cases.
Hypothyroidism can occur due to various circumstances. The thyroid gland may produce too little thyroid hormones or not secrete enough because of a lack of adequate TSH or TRH secretions by the pituitary gland and hypothalamus. There could also be a problem in the conversion of T4 to the active T3 form, but one of the most common causes is autoimmune thyroid disease or Hashimoto’s thyroiditis. In this case, the body recognises thyroid antigens as foreign, resulting in an attack towards the thyroid tissue and its progressive destruction.
Some of the common symptoms of hypothyroidism are fatigue, loss of energy, decreased appetite, cold intolerance, dry skin, hair loss, muscle and joint pain, weight gain, menstrual disturbances and impaired fertility.
Of course the diagnosis is made by a specialist and confirmed by laboratory testing for TSH, T3, T4 and, in case of autoimmune thyroiditis, by checking for thyroid antibodies as well.
Conventional treatment includes medications that contain synthetic or animal derived thyroid hormones to replace the ones that aren’t produced by the body and can contain only T3 or T4 or a combination of both. In the case of autoimmune disease, dietary adjustments and supplementation have been found helpful alongside medications. For example, supplementing selenium has been proved to lower antibodies levels easing some of the symptoms.
Hyperthyroidism on the other hand, occurs when the thyroid gland produces excessive amounts of thyroid hormone, resulting in acceleration of the body’s metabolic rate and it can often be treated efficiently with medication. One of the main causes can be an autoimmune thyroid disease called Grave’s disease, characterised by a variety of circulating antibodies against thyroid tissues. Some of the symptoms observed in hyperthyroidism include hyperactivity, palpitations, nervousness, anxiety, weight loss despite increased appetite, reduction in menstrual flow or absence of menstruation and heat intolerance.
Whether you’re presenting with a thyroid condition or want to support its function, maybe because you have a history of thyroid diseases in the family or simply to promote better health, there are foods that can be beneficial for this little, but essential, gland.
It’s important to focus on nutrients that are needed in both the production of thyroid hormones, but also in the conversion of T4 to the active form T3.
One of these necessary nutrients is iodine, which is found in seaweed and mineral salt and tyrosine, both required for thyroid hormone formation. Your body can manufacture tyrosine from the amino acid phenylalanine, but dietary tyrosine consumption is still important and, while it’s present in high amounts in dairy products, it can also be found in peanuts, almonds, avocados, bananas, lima beans, pumpkin seeds and sesame seeds.
Zinc and copper are two minerals which are necessary for the conversion of T4 to T3. Plant-based sources include pumpkin and sunflower seeds, squash seeds, wheat germ, spinach, cacao, beans, mushrooms, spirulina, cashews and avocado.
Another key nutrient for thyroid hormone synthesis, along with their activation and metabolism, is selenium which is present in Brazil nuts, mushrooms, oats, whole grains and sunflower seeds.
T3 and T4 production and metabolism also requires B vitamins, especially B2, B3 and B6 found in cruciferous vegetables and dark leafy greens, along with peanuts, hazelnuts, brown rice, potatoes, avocados, dried plums and bananas.
It’s extremely important to include a variety of antioxidant rich foods as well, to reduce the oxidative stress caused by hypothyroidism and to buffer the low antioxidant status prevalent in hyperthyroid states. The main ones to focus on are vitamins A, C, E and selenium. Vitamin A in the form of beta-carotenes is present in pumpkin, cantaloupe, mango, squash, sweet potato, spinach and carrots, while vitamin C is in kiwis, oranges, grapefruit, strawberries, tomatoes, sweet red peppers or broccoli. And vitamin E is abundant in avocados, nuts, seeds, sweet potatoes, asparagus, tomatoes, turnips and spinach.
Watch for goitrogens
Make sure to eat a varied diet mainly based on whole foods and you’ll have a healthy dose of thyroid supportive nutrients without problems.
One of the groups of foods that are sometimes recommended to be limited are ones containing goitrogens, which are compounds tending to block iodine absorption, which could be an issue if you’re iodine deficient. And while in the past this was the most common cause of hypothyroidism, these days it occurs much more rarely.
Also, for people that are already taking thyroid medications, goitrogens found in foods like brassica vegetables, cassava, soybeans, peanuts, pine nuts or millet, don’t seem to cause too much of a problem. Simply steam your cruciferous vegetables like cabbage, broccoli, Brussels sprouts, kale, cauliflower, mustard, turnips and cook or roast your beans, nuts and millet, so that the goitrogenic compounds can be highly reduced.
Always talk to a GP if you want to check your thyroid function and test hormone levels. Consult a nutritional professional as well to improve your diet alongside medications, if prescribed, or only with specific nutrients, foods and lifestyle interventions if that’s what has been suggested.
Alessandra Felice (ND Dip CNM)
Alessandra is a nutritional therapist and medicinal chef, who trained with the Natural Gourmet Institute for Health and Culinary Arts in New York and the College of Naturopathic Medicine in London.