Thyroid Hormone Affects the Whole Body

By Dr. Linda J. Dobberstein, DC, Board Certified in Clinical Nutrition

January 8, 2018

Thyroid Hormone Affects the Whole Body
It is well-known that the thyroid gland and its hormones are needed for health and metabolism. But what does that mean? Thyroid hormones affect the entire body in ways that are often not thought about. From the very young with growth and maturation, to adulthood with fertility, weight management, energy, heart disease, to the elderly with aging bones, memory and learning, constipation, and more, thyroid hormone affects everything. Inadequate thyroid gland support and impaired hormone function, even at subclinical levels, can impact healthy aging and well-being. Protection and fortification of this system must be a priority for healthy metabolism, and aging well.

Heart, Cholesterol, Blood Pressure

Thyroid hormone is needed by the heart to maintain function and rhythm. If this system is not performing well heart rate changes and arrhythmias may occur. Blood pressure is affected by hyper and hypothyroidism due to the change in the renin-angiotensin-aldosterone system (RAS). Total cholesterol, LDL cholesterol, triglycerides, HDL cholesterol are all impacted by thyroid hormones. Cardiovascular risk and disease increases with poor thyroid function even in children and teenagers who have subclinical hypothyroidism.


Bones need thyroid hormone to grow during childhood, to reach peak bone mass, and to maintain a proper balance of bone build-up and break-down through adulthood. T3 thyroid hormone has a synergistic effect with parathyroid hormone, vitamin D and several other proteins and enzymes that affect bone formation and turnover. In children with hypothyroid, they may experience stunted growth. Adults and children may face higher risk of osteoporosis.

Adrenal Glands, Growth, Fertility, Menstrual Cycle

Hypothyroidism correlates with diminished adrenal function. The size and weight of the adrenal glands are often smaller in underactive thyroid. This is associated with decreased production of adrenal steroids, like cortisol.

Growth spurts, initiation of puberty, and fertility depend on healthy thyroid function. Infertility and repetitive miscarriages may occur with thyroid dysfunction. Other hormones like luteinizing hormone (LH) decrease in hypothyroidism, which challenge menstrual cycle regularity and flow. PMS and menopause symptoms may increase.

Muscles, Mitochondria and Energy Production

Muscle energy and strength may be affected by both hyperthyroidism and underactive thyroid. Muscle weakness, loss of strength, muscle fatigue, diminished muscle repair, difficulty building new muscles, cramps, and even muscle breakdown or rhabdomyolysis may occur with impaired thyroid function. Those who are treated with a cholesterol-lowering statin medication and have untreated hypothyroidism may be at higher risk of muscle breakdown or rhabdomyolysis due to their overlapping stress effect on muscles.

Mitochondrial function is profoundly impacted with either under- or overactive thyroid problems. Energy problems, calorie burning and other significant metabolic changes occur because of impaired mitochondrial function and decreased thyroid hormone. In hypothyroidism, it is like trying to start a fire with damp firewood. The energetic process just smolders and does not create heat or energy. Hyperthyroidism stresses mitochondria like a fire that has gasoline dumped on it, only to burn hotter and faster provoking more free radical stress and inflammation.

Nerves, Brain, and Pain

Thyroid hormones impact the myelin sheath or the protective fatty layer around nerve tissue. Overactive and underactive thyroid problems may cause high levels of oxidative stress and inflammation that damages the myelin sheath. Impaired thyroid hormone function affects the hippocampus or memory center of the brain. The result is memory and learning difficulties. Pain sensitivity increases, neurotransmitter levels are altered, mood changes, and neuropathy may occur.

Gall Bladder, Liver, Pancreas/Insulin and Gut

Gallbladder problems can occur because of low thyroid function. Constipation occurs with hypothyroidism and diarrhea occurs with hyperthyroidism. Insulin resistance may occur with both hyperthyroidism and hypothyroidism. Fatty acids build up and are not burned for fuel. This may contribute to some cases of non-alcoholic fatty liver disease (NAFLD). Gut dysbiosis or imbalanced gut bacteria may lead to or occur because of thyroid dysfunction.

Immune Cells

The immune system is directly affected by thyroid hormone balance, as every single immune cell has receptor sites for thyroid hormone. Thyroid hormone is needed to help mature and regulate the T and B cells of the immune system. Thyroid gland function is also impacted by the immune system, so it is a reciprocal relationship. Most thyroid problems are autoimmune, i.e. the immune system attacks the thyroid gland or prevents the thyroid hormone from working because of inflammation.

Blood Flow

Blood clots like DVTs, pulmonary embolisms/PEs, etc. may occur with thyroid dysfunction. Subclinical hypothyroid and elderly may pose a higher risk for blood clots, but this may occur in younger adults too. In hypothyroidism, blood doesn’t travel as fast and blood cells have a greater tendency to clump together, resulting in clots. Hyperthyroidism may also lead to changes in blood flow and hemodynamics, which may also result in blood clots or bleeding disorders

The end result is that health risks increase, and significant loss of health may occur with any type of thyroid disruption including subclinical thyroid dysfunction.

Healthy Adrenal Function and Stress

We saw earlier that poor thyroid function correlates with stressed adrenal gland function. Therefore, it is essential to provide simultaneous nourishment and support to help optimize adrenal gland function. 

Thyroid symptoms range from forgetfulness, depression, anxiety, frequent colds/infections, constipation/diarrhea, elevated cholesterol, changes in blood pressure and heart rate, fatigue, change in temperature regulation, sleep problems, blood sugar imbalances, weight changes, muscle pain, weakness and fatigue, gall bladder and liver problems, mitochondria dysfunction, nerve symptoms, and skin problems, etc. Every system in the body is affected. Western medicine likes to compartmentalize symptoms and systems, but everything is connected in the body. Like the complexity of its function, thyroid hormones need several different nutrients to function. Nutritional fortification is necessary for healthy thyroid function. If you find yourself with a long-list of symptoms, work with your health care provider for proper evaluation and use these tips and those found in last week’s article, Tips to Make Your New Years Resolution Successful to help ensure healthy nutrition for your thyroid.

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