Do you feel tired? Is your mood unusually low? Do you have steady weight gain despite eating well and exercising? If you answered “yes,” your thyroid may be struggling to keep up with the demands of daily life.
Your thyroid gland effectively sets your body’s thermostat and metabolism. It can be sluggish when the conversion from your body’s primary thyroid hormone – thyroxine (T4) – to the “active” or useable form – triiodothyronine (T3) – is impaired. Effectively, the thyroid acts as a bellwether for stress on the body.
A sluggish thyroid is often termed subclinical hypothyroidism because patients can exhibit some of the classic symptoms of hypothyroidism – fatigue (especially in the morning), weight gain, cold hands and feet, sluggish bowels, dry skin and hair – but without the hallmark lab test results needed for a true diagnosis.
Healthy thyroid hormone production is regulated by the hypothalamus. Through a multi-step process, it produces thyroid releasing hormone (TRH) which promotes thyroid stimulating hormone (TSH) from the pituitary gland that then influences the thyroid – a butterfly-shape gland in your neck – to produce the thyroid hormone T4. The thyroid hormones influence virtually every tissue in the body.
If you suffer from a sluggish or a subclinical hypothyroid condition, TSH is mildly elevated but T4 levels are not. Another cause is when T4 is not being converted to the “active” T3 form inside your cells. The good news is you don’t have a frank hypothyroid condition, however, it is a red flag that you should address areas like your diet, exercise, and lifestyle factors (i.e. sleep and stress management) that can all influence thyroid function.
#1 Too Much Stress
Low thyroid function is often secondary to some type of stressor. 1 TSH production is lowered under times of stress. 2,3 For example, athletes training intensely in preparation for a competition will typically see decreased TSH concentrations as the training load increases. But, once the training stressor is removed levels quickly return to baseline. Long, busy days at work or taking care of family can also be a major stressor just like training, however unlike the athlete you don’t get an “off-season” to allow your levels to return to baseline. The stressor is always present; contributing to elevated cortisol stress levels, lower thyroid hormone production, and impaired conversion of T4 to active T3 hormone. 4
#2 Too Many Grains
Grains may promote inflammation in some people and chronic, systemic inflammation can impair healthy thyroid function. 5 Numerous studies have linked gluten – a protein found in grains like wheat, barley, spelt and rye – to autoimmune thyroid disease called Hashimotos. 6,7,8 If you suffer from celiac disease or even a gluten intolerance, then the likelihood of you suffering from an autoimmune thyroid condition, like Hashimoto’s thyroiditis, is significantly increased. 9
Even if you don’t suffer from an autoimmune condition, the regular consumption of excessive gluten (if you suffer from non-celiac gluten sensitivity) can lead to intestinal permeability 10 and chronic inflammation which can hamper the conversion of T4 to T3. 11 Not surprisingly, intestinal permeability and inflammation are commonly seen in those with subclinical thyroid disorders.
#3 Imbalance Gut Microbiota
Too much stress, lack of sleep, poor blood sugar control can all lead to intestinal dysbiosis, the overabundance of “bad” gut bacteria. Harmful bacteria contain lipopolysaccharides (LPS), molecules on the bacteria cell wall that can slow thyroid hormone production and conversion. 12
#4 Nutrient Deficiencies
The standard American diet (SAD) is deficient in many key nutrients that are important for a healthy thyroid. These deficiencies are detailed below.
#5 Too Many Medications
Common drugs that prevent the conversion of T4 to T3 include beta-blockers for hypertension, oral contraceptives, hormone replacement drugs for menopause, and corticosteroids like prednisone. Over-the-counter antacids, heartburn medications, excessive antibiotics or the use of statins can also lead to a myriad of nutrient deficiencies, including iron, zinc, selenium and vitamin D.
Food-Based Solutions For A Healthy Thyroid
Your diet should provide all the building blocks you need to support optimal thyroid output, allowing you to restore low energy, trim your waistline and upgrade your overall health. Here is a list of wholefoods that provide the key thyroid nutrients you need:
Selenium is essential for healthy thyroid function and the conversion of T4 to active T3. You’ll need approximately 100-200mcg daily. Brazil nuts are far and away the best source of selenium, with only two nuts providing a whopping 190 mcg daily. Other good sources include mushrooms, eggs, shrimp, halibut, tuna, chicken, turkey and asparagus.
Diets high in zinc can help improve the conversion of T4 to T3. 13 Oysters are head and shoulders above the rest when it comes to zinc, providing a robust 78mg per 100g serving. Virtually all animal proteins are also great sources of zinc – beef, venison, bison, lamb, pork, etc.
While iodine deficiency is the root cause of most cases of hypothyroidism worldwide, in Western countries, Hashimoto’s autoimmune thyroiditis actually accounts for the majority of cases. 14,15 If you suffer from an autoimmune thyroid condition you want to avoid taking an iodine supplement because it can exacerbate your condition. 16
To get your ideal dose of iodine, try adding more sea vegetables to your nutritional arsenal. Seaweeds like kelp, dulse, kombu, and wakame can be eaten as snacks, or make your own “seaweed shaker” by finely chopping up seaweed and placing in a traditional salt shaker. Sprinkle it on meals for a tasty and effective condiment.
Tyrosine, a conditionally essential amino acid, is the building block for both T4 and T3 hormone and dopamine, the “feel-good” neurotransmitter that helps ward off low mood and depression. Tyrosine-rich foods include duck, eggs, mustard greens, spinach, seafood and seaweed.
Sun exposure and getting your daily dose of vitamin D is crucial for optimal thyroid health. Low vitamin D levels have been associated with Hashimoto’s autoimmune thyroiditis. 17 If you live in a city with a true winter climate, then you should consider supplementing with 1,000-2,000 IU daily, unless otherwise specified by your doctor.
Dr. Marc Bubbs ND, MS CISSN, CSCS
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 Abdullatif H et al. Reversible subclinical hypothyroidism in the presence of adrenal insufficiency. Endocr Pract 2006 Sept-Oct;12(5):572.
 Van Der Pomp G et al. Elevated basal cortisol levels and attenuated ACTH and cortisol responses to a behavioural challenge in women with metastatic cancer. Psyochoneuroendocrinology 1996 21(4):361-374.
 Sapolsky R et al. The neuroendocrinology of stress and aging: the glucocorticoid cascade hypothesis. Endocr Rev 7:284-301.
 LoPresti J, Nicoloff T. Thyroid response to critical illness. Endocrinology of Critical Disease. Human Press. Totowa NJ. 1997, pp157-173.
 Wolters V. Genetic background of celiac disease and its clinical implications. Am J Gastroenterol 2008;103(1):79-88.
 Manairdi, E. Thyroid-related autoantibodies and celiac disease: a role for a gluten-free diet? J Clin Gastroenterol 2002 Sep;35(3):245-8.
 Spadaccino A et al. Prevalaence of celiac disease in patients with autoimmune thyroid diseases. Autoimmunity 2008 Feb;41(1):116-21.
 Hadithi M et al. Celiac disease in Dutch patients with Hashimoto’s thyroiditis and vice versa. World J Gastroenterol 2007 Mar 21;13(11):1715-22.
 Elfstrom P et al. Risk of thyroid disease in individuals with celiac disease. J Clin Endocrinol Metab 2008 Oct;93(10):3915021. Epub 2008 Jul 8.
 Fasano A.Zonulin and its regulation of intestinal barrier function: the biological door to inflammation, autoimmunity, and cancer.Physiol Rev 2011 Jan;91(1):151-75.
 Vaarala, O et al. The perfect storm for type-1 diabetes:the complex interplay between intestinal microbiota, gut permeability, and mucosal immunity. Diabetes 2008 Oct;57)10):2555-2263.
 Van der Pol T et al. Interleukin-1 receptor blockade does note ffect endotoxin-induced changes in plasma thyroid hormone and thyrotropin concentrations in man. J Clin Endcorinol Metab. 1995;80(4):1341-1346.
 Maxwell C et al. Effect of Zinc Supplementation on Thyroid Hormone Function. Ann Nutr Metab 2007;51:188–194.
 Andersson M, et al. “Current global iodine status and progress over the last decade towards the elimination of iodine deficiency.” Bulletin of the World Health Organization 83.7 (2005): 518-525.
 Bailleres. Autoimmunity and hypothyroidism. Clin Endocrinol Metab 1988 Aug;2(3):591-617.
 Surks M, Sievert R. Drugs and thyroid function. NEJM 1995;333(25):1688.
 Drugarin D. The pattern of Th1 cytokine in autoimmune thyroiditis. Immunol Letts 2000;71:73-77.