Thyroid and Adrenal Malfunction:
Common Causes of Fatigue and Exhaustion
By Nieske Zabriskie, ND
Fatigue is one of the most common complaints experienced by the general population. In fact, one study demonstrated that 24 percent of patients in outpatient care report fatigue is a major health problem.1 Fatigue can be a particularly challenging condition for both the patient and the physician as it can have numerous causes and is often difficult to identify the origin. However, two common causes of fatigue are endocrine dysfunction of the thyroid or adrenal glands.
Hypothyroidism, or low thyroid hormone function, is a condition characterized by a decreased basal metabolic rate. Hypothyroidism frequently is characterized by decreased conversion of inactive thyroid hormone to active thyroid hormone, as well other conditions such as autoimmunity. Thyroid hormones are important for numerous physiological functions in the body. These hormones stimulate an increase in size and number of mitochondria, the site of energy production in cells. This directly affects the overall metabolic rate in the body. Thyroid hormone is also important for normal growth, transcription of genes, stimulates carbohydrate and fat metabolism, increases heart rate, blood volume, strength of heartbeat, muscle contraction, increases secretions necessary for digestion and gastrointestinal motility, and increases the secretion of other endocrine hormones. Thus, low thyroid hormone function affects all systems in the body.
Most commonly, hypothyroidism presents with fatigue, lethargy, weakness, dry skin, course hair, slowed speech, cold intolerance, and hoarseness. It may also present with muscle and joint pain, muscle cramps, headaches, brittle nails, thinning hair, carpal tunnel syndrome, edema, constipation, weight gain, hypertension, sleep apnea, depression, cognitive impairment, and swelling around the eyes. One of the most common nutritional causes of thyroid dysfunction worldwide is iodine deficiency.
Iodine is a trace element required in the diet for several physiological functions. Iodine deficiency is a world-wide problem and is associated with numerous health conditions such as hypothyroidism, an enlarged thyroid called a goiter, congenital hypothyroidism known as cretinism, cognitive disorders, neurological disorders, and breast disease.
Iodine is converted to iodide before absorption in the intestines. Iodine is incorporated into thyroid hormone precursors, which further combine to form the thyroid hormones thyroxine (T4) and triiodthyronine (T3). An enlarged thyroid, or goiter, is the most overt sign of iodine deficiency. Hypothyroidism due to iodine deficiency presents with a decrease in thyroid hormones as well as decreased thyroid stimulating hormone (TSH).
Iodine deficiency can be caused by several factors such as low levels of iodine in the soil or water in particular areas and ingestion of large amounts of goitrogens (substances that block iodine absorption and inhibit the thyroid gland). Common goitrogens include cruciferous vegetables, cassava, millet, and soya flour.
Intake of particular elements, which compete with iodine for uptake and utilization, may also be a factor. In the early 1960s, iodine was added to bread as a dough conditioner. But in the 1980s, bromine replaced iodine in the bread-making process. Bromide is known to cause goiters, the term for enlarged thyroid glands, because it competes with iodine for use by the body, producing a relative iodine deficiency even when iodine intake is sufficient.2 Sangster, et al. reported a decreased ability to concentrate and sleepiness in normal male subjects ingesting sodium bromide.3 These symptoms are consistent with hypothyroidism caused by iodine deficiency.
Iodine was first added to sodium chloride (table salt) in the 1920s in the US. That practice gave a false sense of iodine sufficiency and resulted in the public relying on iodized salt for supplementation instead of the previously used forms of iodine and iodide found in the Lugol solution, a 5 percent solution of 50 mg iodine and 100 mg potassium iodide per milliliter that was commonly used by medical practitioners. However, by the 1950s, most physicians forgot their predecessors were using amounts of iodine/iodide two orders of magnitude greater than the amounts present in the average daily consumption of table salt. In addition, although supplementation with both iodine and iodide produces the most desirable effects, table salt supplies only iodine.
Clinicians have found that consuming iodine in a form similar to the Lugol solution (as in Iodoral®) can help restore energy levels in hypothyroid patients. An iodine sufficiency test can also help determine the proper level of supplementation required.
Low Adrenal Function
The outer cortex of the adrenal glands is responsible for secreting several steroid hormones including cortisol, aldosterone, and dehydroepiandrosterone (DHEA). Cortisol is the main hormone involved in the stress response and imbalanced cortisol levels can contribute to fatigue and exhaustion. Cortisol is responsible for increasing glucose synthesis in the liver for energy, breakdown of protein, and inhibiting glucose uptake and utilization into cells resulting in mild insulin resistance. Excess cortisol as from increased stress results in suppression of inflammation and immune function and increases appetite, energy intake, and central weight gain. It suppresses bone formation, causes loss of muscle mass and weakness, changes in mood and sleep, and increases blood pressure. Prolonged activation of the stress response may lead to adaptation or adrenal exhaustion in which cortisol levels may drop to insufficient levels causing fatigue or illness.4 Primary adrenal insufficiency is characterized by fatigue, muscle weakness, weight loss, low blood pressure, and possibly darkening of the skin.5
Studies show that psychosocial stress activates the hypothalamus-pituitary-adrenal axis and causes an increase in morning cortisol levels, which correlated to the subjects' reports of increased fatigue and tension-anxiety.6
Herbal preparations have historically been used to modulate adrenal function. Adrenal adaptogens are believed to balance abnormal adrenal hormone output; increasing low levels of hormone or decreasing elevated hormone levels. Adaptogens are described as plants that produce a non-specific response increasing the resistance to multiple types of stressors. Many of these herbs have a long history of use in countries such as China and Russia.
Eleutherococcus has been traditionally used for anti-stress and anti-fatigue properties as well as immune stimulating action. One study demonstrated that supplementation with Eleutherococcus for 2 months decreased fatigue severity and duration, particularly in subjects with moderate fatigue and fatigue that lasted for five or more years.7 However, animal studies measuring forced swimming time show that supplementation with Eleutherococcus inhibits stress-induced cortisol increase and reduction of the natural killer cells of the immune response, and increases swimming time.8
Crataegus sanguinea extract
The fruit of Crataegus, or hawthorn, is traditionally used as a heart tonic. Numerous studies indicate the hawthorn increases coronary blood flow and force of contractions, decreases abnormal heart rhythms, and may decrease blood pressure. Additional evidence suggests that Cratageus may lower total serum cholesterol, triglycerides, and low-density lipoprotein cholesterol (LDL).9-10
Schisandra is adaptogenic herb traditionally used in China for generalized support. Studies show that it may increase endurance, concentration, and coordination as well as provide antidepressant, antioxidant, and anti-inflammatory action.11 Evidence suggests that adaptogens such as Schisandra support the stress response both by affecting the sympathetic-adrenal response with short term administration as well as supporting the hypothalamic-pituitary-adrenal axis with longer-term administration.12
Ajuga turkestanica and Rhaponticum carthamiodes extract
These herbs contain biologically active constituents known as ecdysteriods. Research in the Ukraine suggests that these constituents provide adaptogenic, anabolic or rebuilding activity, as well as antioxidant, anti-free radical, immune modulating, stimulating, liver protecting, and cholesterol-lowering actions.13 Ajuga turkestanica extract contains turkesterone, possibly the most potent ecdysteroid.14
Aralia mandshurica extract
Aralia mandshrica, also known as Aralia manchurica or Manchurian Thorn Tree, has historically been used in Russia as an adaptogen for fatigue, weakness, headaches, depression, immune support, and stress-overload. One study showed 90 percent success rate using this herb in individuals with stress overload and weakness.15
Rhodiola is a popular adaptogen. One study investigated supplementation with a single dose of Rhodiola on mental tasks performance under stress and fatigued situations. The study demonstrated significantly decreased fatigue in the treatment group compared to the placebo group.16 Additionally, a second study evaluated students during examinations with supplementation of Rhodiola. The study found significant improvement in mental fatigue, physical fitness, and neuron-motor tests in the treatment group compared to placebo.17 Animal studies have also shown that Rhodiola supplementation selectively moderates stress-induced anorexia.18 Rhodiola has also been reported to have antidepressant, anti-cancer, cardioprotective, and central nervous system supportive activity. It is also believed to provide support for stress-induced conditions such as poor sleep, headaches, and irritability by influencing opioid peptide levels and activity.19
Myricetin is a bioflavonoid found in many fruits and berries. Research indicates that myricetin has potent antioxidant and anti-inflammatory properties.20 Additionally, this flavanol shows anti-bacterial, anti-viral, anti-cancer activity, and potent free radical scavenger action, decreasing oxidative stress and providing generalized support to cells.21
Endocrine abnormalities are commonly associated with the symptoms of generalized fatigue and weakness. Investigation into thyroid and adrenal dysfunction is indicated in stressed and tired individuals. Natural support can help balance these conditions.
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