The endocrine system is a complex network of glands that produce and secrete hormones, chemical messengers that regulate various physiological processes in the body. These hormones travel through the bloodstream to target organs and tissues, where they exert their effects, coordinating processes such as metabolism, growth and development, reproduction, and one’s response to stress. Through sensitive feedback loops, the endocrine system maintains balance to ensure the body's internal environment runs smoothly and functions optimally.
Metabolism:
Healthy thyroid function is key in ensuring we are able to convert the resources we gain from foods into energy at an appropriate rate.
Thyroid-Stimulating Hormone (TSH) is produced by the pituitary gland, and is responsible for stimulating the thyroid gland to produce thyroid hormones which include triiodothyronine (T3) and thyroxine (T4).
T4 is the primary hormone produced in the thyroid that then gets converted to the more active T3 form when sent into circulation. Both are crucial for regulating our metabolism and energy usage.
An abnormal TSH level indicates overt issues with the thyroid, where imbalances in T4 and T3 in light of a normal TSH can be a sign of subclinical thyroid dysfunction.
When TSH is elevated, T4 and T3 levels often drop in response. This is the case in Hypothyroidism or Hashimoto’s, in which case one experiences symptoms of slowed metabolism such as fatigue, weight gain, constipation and low mood.
When TSH is low, T4 and T3 levels go up. This results in Hyperthyroidism or Graves, which results in symptoms of accelerated metabolism such as weight loss, anxiety, diarrhea, and heart palpitations.
Glucose & Appetite Regulation:
Insulin is the key hormone responsible for regulating blood sugar levels by facilitating the uptake of glucose into cells for energy. When blood sugars remain high over time, circulating insulin becomes less responsive to the present glucose and the body produces more insulin to complete the same task. This results in a process known as insulin resistance, which can lead to type 2 diabetes. Signs of insulin resistance include high blood sugar levels, increased thirst, frequent urination, and fatigue.
Our fat cells produce a hormone called leptin, which regulates our appetite by telling the brain when the body is full. Ghrelin, which originates from our stomach tissue, works to oppose leptin by stimulating one's appetite.
Stress Response:
Cortisol is made in the zona fasciculata of the adrenal cortex, and plays a key role in our sleep wake cycle, the body's response to stress, metabolism, and blood pressure. When we are put into a stressful situation, our body responds by activating our sympathetic nervous system and triggering a “fight or flight” response. This results in a surge of cortisol, which raises our blood pressure and increases circulating sugars that can be easily accessed for fuel if we have to act quickly. This response, however, was meant to be acutely advantageous versus our persistent state. Chronic stress or adrenal dysfunction can lead to elevated or reactively suppressed cortisol levels which often results in weight gain, insomnia, anxiety, and digestive issues.
Dehydroepiandrosterone (DHEA) is another adrenal hormone that serves as a precursor to sex hormones and influences libido, mood, and immune function. DHEA deficiency or excess may result in changes in libido, mood swings, fatigue, and immune dysfunction. This level will also typically elevate in states of acute stress.
Reproductive Success:
Estrogen and progesterone are a woman’s main reproductive hormones. Together, they regulate the menstrual cycle, promote growth and development of the reproductive organs, maintain reproductive health, and support healthy bone density. Both naturally fluctuate throughout the menstrual cycle, however, inappropriate imbalances can lead to symptoms including irregular periods, heavy menstrual flow, painful cramping, breast tenderness, headaches, mood swings, hot flashes, and decreased bone density.
Both men and women produce testosterone but this is a key hormone in men to regulate male sex organ development, libido, muscle mass, bone density, and mood. Low testosterone levels in men can lead to decreased libido, erectile dysfunction, fatigue, and decreased muscle mass. In women, excess testosterone may cause acne, hirsutism, and menstrual irregularities that commonly characterize Polycystic Ovarian Syndrome (PCOS).
Prolactin is secreted by the pituitary gland to promote lactation in breastfeeding women. That said, prolactin also influences reproductive function and metabolism in both women and men. In times of acute stress, prolactin levels often elevate. Elevated prolactin may disrupt production of estrogen and progesterone which can negatively affect menstrual cycles, fertility, and lactation. Conversely, low levels can affect reproductive function and bone health.
Growth & Development:
Growth Hormone (GH) stimulates growth and development, regulates metabolism, and maintains muscle and bone mass.Deficiency in growth hormone can lead to stunted growth in children and decreased muscle mass and bone density in adults.
Parathyroid Hormone (PTH) regulates calcium and phosphate levels in the blood and bone remodeling. Hyperparathyroidism (high PTH) can lead to hypercalcemia, kidney stones, and bone loss. Hypoparathyroidism (low PTH) may cause hypocalcemia, muscle cramps, and seizures.
Sleep Wake Cycle:
Melatonin, together with cortisol and a symphony of neurotransmitters, is responsible for regulating the sleep-wake cycle & circadian rhythms. Disruption in melatonin levels can lead to sleep disorders, insomnia, and mood disturbances.
Understanding where your hormones stand is essential for optimizing your well-being and addressing any imbalances that may be impacting your health.
Naturopathic doctors are equipped with blood tests to determine the status of hormone levels, as well as tools to manage any identified imbalances and their associated health complications.