WHAT IS THE THYROID? WHY IS IT IMPORTANT? WHAT IS HYPOTHYROID?
The thyroid is one of the largest endocrine glands and is found in the neck is has a wide variety of functions essential in maintaining normal function. The thyroid gland produces triiodothyronine (T3) and thyroxine (T4). These hormones regulate the rate of metabolism and affect the growth and rate of function of many other systems in the body. The T3 hormone is the biologically active form of thyroid hormone responsible for carrying out the essential functions of the thyroid T3 and T4 are synthesized from both iodine and tyrosine. The thyroid also produces calcitonin, which plays a role in calcium homeostasis. The thyroid also controls how quickly the body uses energy, makes proteins, and controls how sensitive the body is to other hormones
Every cell in the body has receptors for thyroid hormone. These hormones are responsible for the most basic aspects of body function, impacting all major systems of the body: brain, the G.I. tract, the cardiovascular system, bone metabolism, red blood cell metabolism, gall bladder and liver function, steroid hormone production, glucose metabolism, lipid and cholesterol metabolism, protein metabolism and body temperature regulation. You can think of the thyroid as the keystone in an arch, if you break that keystone, the whole structure comes tumbling down.
Hypothyroidism is a condition in which the thyroid does not produce enough thyroid hormone, or an inability in the body to transform T4 to T3. That’s why people with hypothyroidism experience everything from weight gain and depression to infertility, bone fractures and hair loss. Hypothyroid can have autoimmune issues underlying the cause or it can be occurring through some other vector such as cortisol deregulation or iodine deficiency. Roughly, 9 out of 10 hypothyroid disorders in the United States are indeed autoimmune “Hasimoto’s thyroiditis, and can be attributed to certain lifestyle factors (specifically diet). I can try and dig a little deeper on your exact case if you know if you have either high TSH (thyroid stimulating hormone) levels, Low T3, or if it is autoimmune base, but I will try and address all of these points, beginning with the question about goitrogenic foods.
Goitrogens are substances that suppress thyroid function by interfering with the uptake of iodine, an essential element which enables the thyroid gland to produce thyroid hormones. Three iodine molecules are added to make T3 (triiodothyronine), and four for T4 (thyroxine). This can result in an enlargement of the thyroid, i.e. a goiter. This is akin to throwing fuel into the fire if you already have hypothyroidism due to the lack of iodone. Iodine deficiency as the cause of hypothyroid is extremely rare in the United States and is generally found as the cause in developing countries. Now, assuming the thyroid is not autoimmune and goitrogenic foods may cause an issue, let’s see what that would look like. There has been a lot of talk and debate in the health field about goitrogen containing foods and their effect on people with hypothyroid disorders. The mechanism described in the literature is sound; however, I did a lot of digging and a pretty thorough review of the actual research and literature surrounding it and here are my conclusions on the topic.
The compound that acts as a goitrogen in cruciferous vegetables is called thyiocyanate. The research has found that excessive consumption of raw goitrogen containing vegetables along with an iodine deficient diet can suppress thyroid function. So, yes there is some truth to the hypothesis of goitrogen containing cruciferous vegetables exacerbating hypothyroid; however, there are some key aspects to keep in mind. These studies were based upon either animal models or populations where “excessive” amounts of raw goitrogen containing vegetables were consumed and had environmental or controlled factors that led to decreased dietary iodine intake. Also, thyiocyanate (the goitrogenic compound in these foods) is greatly reduced when cooked. I would have to conclude that if you are not Iodine deficient, have a large variety of other vegetables in your diet, and do not consume them in excessive quantities, having some well cooked vegetables a few times a week probably will not a significant if any impact on your thyroid function. Now there is one caveat to that statement, soy and millet are also goitrogen containing foods and the compounds in them are not reduced in the cooking process so I would be more cautious with those. Some excellent non-goitrogenic vegetables are carrots, onion, butternut squash, acorn squash, zuchinni, turnips, and parsnips.
OTHER MECHANISMS FOR HYPOTHYROIDISM
One of the largest contributors to hypothyroidism aside from autoimmune based hypothyroidism is an improperly functioning adrenal system, specifically the overproduction of Cortisol. Cortisol is a corticosteroid hormone involved in metabolism of carbohydrates, proteins, and fats, affects the blood sugar levels, a key player in the inflammatory process and is crucial in physiological responses to stress. Cortisol also plays an important role in regards to your thyroid through the blood glucose vector. Cortisol is extremely effective in raising blood glucose, which works with your cell receptors to receive T3 from the blood to the cells. In a normally functioning thyroid, it produces roughly 80% T4 and 20% T3 and the levels of T3 necessary for normal function are converted from T4 into T3. Cortisol directly impacts your ability to convert T4 to T3, remember the key biologically active hormone produced by your thyroid? Generally, if cortisol levels are elevated your body tends to produce a non-functioning version of the T3 hormone. Another feature of cortisol is that during extended elevations in cortisol due to chronic stress, the liver’s ability to clear excess estrogens from the blood is dramatically decreased. This results in excess estrogen in the blood, which increases levels of thyroid binding globulin, causing the T3 and T4 to become inactive.
An autoimmune cause accounts for approximately 90% of adult hypothyroidism, mostly due to Hashimoto's disease. Hashimoto’s is an autoimmune disease in which the thyroid gland is attacked by a variety of cell- and antibody-mediated immune processes. The majority of Hashimoto patients are women aged between 20 and 60 years old and nearly 10% show overt hypothyroidism. The mechanisms behind autoimmune based “Hashimoto’s” disease are complex and can be greatly remedied by diet. I won’t go into great length here but, If it is autoimmune there are some excellent resources and protocols out there to help and have actually reversed Hashimoto’s in some cases. These cases are based upon the idea that your diet is the cause of your autoimmune response that is responsible for causing Hashimoto’s. The mechanism described as the cause is sounds, logical, and has been scientifically proven. The elimination of certain gut irritants such as grains, legumes, and dairy, for a period of time to see if they are the cause has proven to be extremely helpful to these people. At the end of the post is the list to the cases and the resources, so if it is a case of autoimmune hypothyroid check them out!
NATURAL OPTIONS TO PROMOTE THYROID FUNCTION
Selenium deficiency has been tied to hypothyroid and increasing dietary selenium has been shown to support thyroid function. It supports efficient thyroid hormone synthesis and metabolism and protects the thyroid gland from damage from excessive iodine exposure. Selenium is essential in the conversion of T4 to T3, the active form of thyroid hormone. As previously mentioned, low T3 can lead to hypothyroid symptoms. A recent study has shown that that selenium supplementation in selenium deficient subjects modulated T4 levels, hypothetically improving conversion to T3, and in cases of severe selenium deficiency, which is entirely possible in a standard Western Diet heavy on grains and plant based proteins, and conversion of T4 to T3 may be impaired, ultimately leading to hypothyroid symptoms. Good dietary sources of selenium includes: brazil nuts, crimini mushrooms, cod, shrimp, tuna, halibut, salmon, scallops, chicken, eggs, shiitake mushrooms, lamb, and turkey.
Vitamin D is another way to help combat hypothyroid through a few different mechanisms. Like thyroid hormones, vitamin D interacts with almost every cell in the body, and vitamin D levels are negatively associate with cortisol, meaning that when cortisol levels are high, vitamin D levels decrease; this is due to the fact that both stress hormones (i.e. cortisol) and vitamin D are produced from cholesterol. When stress and cortisol is high, vitamin D production takes a back seat. A diet low in healthy fats is detrimental to vitamin D function as it is a fat soluble vitamin.
Lastly, make sure you are getting plenty of sleep and exercising appropriately. The sleep issue is a whole subject unto itself but inadequate sleep can be a major proponent of cortisol deregulation. Lack of sleep, both in quantity and quality, can lead to elevated cortisol levels which can exacerbate hypothyroid. Extended periods of exercise, “chronic cardio”, or extreme metabolic conditioning work (think long, knockdown, and drag out, crossfit type workouts) can also result in elevated cortisol levels.
Amino, N. (1988). Autoimmunity and Hypothyroidism. Bailliere's Clinical Endocrinology and Metabolism, 2(3), 591-617.
Arthur, J. R., Nicol, F., & Beckett, G. (1993). Selenium deficiency, thyroid hormone metabolism, and thyroid hormone deiodinases. American Journal of Clinical Nutrition, 57(2), 236S-239S.
Bray, G. A. (1968). Increased sensitivity of the thyroid in iodine-depleted rats to the goitrogenic effects of thyrotropin. Journal of Clinical Investigation, 47(7), 1640-1647.
Chandra, A., Tripathy, S., Ghosh, D., Debnath, A., & Mukhopadhyay, S. (2005). Iodine nutritional status & prevalence of goitre in Sundarban delta of South 24-Parganas, West Bengal. The Indian Journal of Medical Research, 122(5), 419-424.
Ganesh, B. B., Bhattacharya, P., Gopisetty, A., & Prabhakar, B. (2011). Role of Cytokines in the Pathogenesis and Suppression of Thyroid Autoimmunity. Journal of Interferon & Cytokine Research, 31(10), 721-731.
Olivieri, O., Girelli, D., Stanzial, A., Rossi, L., Bassi, A., & Corrocher, R. (1996). Selenium, zinc, and thyroid hormones in healthy subjects: Low T3/T4 ratio in the elderly is related to impaired selenium status. Biological Trace Element Research, 51(1), 31-41.
Pizzuli, A., & Ranjbar, A. (2000). Selenium deficiency and hypothyroidism: A new etiology in the differential diagnosis of hypothyrodism in children. Biological Trace Element Research, 77(3), 199-208.
Wolff, J., Chaikoff, I., Taurog, A., & Rubin, L. (1946). The disturbance in iodine metabolism produced by thyiocyanate: The mechanism of its goitrogenic action with radioactive iodine as indicator. Endocrinology, 39(2), 140-148.
AUTOIMMUNE CASE STUDIES
Autoimmune Case Study #1
Autoimmune Case Study #2
Autoimmune Case Study #3
Information offered by University of Idaho Wellness is not meant to replace advice given by your health care provider.