Chronic constipation is a common complaint of people with an underactive thyroid gland. Poor thyroid function slows down the amount of time it takes for food to move through the intestines. This increases the potential of gut infections from harmful bacteria and yeast, leading to inflammation, malabsorption, and increased risk of developing food intolerances.
The production of gastric acid depends on the hormone gastrin, which diminishes with hypothyroidism. This can cause digestive complaints like bloating, heartburn, gas, and infections. In people with hypothyroidism and low stomach acid, protein deficiency may occur.
Thyroid hormones strongly influence the tight junctions in the stomach and small intestine, which form the impermeable barrier of the gut. Leaky gut (increased intestinal permeability) is a major contributor to thyroid autoimmune diseases like Hashimoto's thyroiditis.
Studies showed that T3 and T4 thyroid hormones protect gut mucosal lining from stress induced ulcer formation. Inflammation in the gut reduces T3 by raising cortisol. Cortisol decreases active T3 levels while increasing levels of reverse T3.
Among other roles, the gut bacteria assists in converting about 20 percent of inactive T4 into the active form of thyroid hormone, T3. Intestinal dysbiosis, an imbalance between pathogenic and beneficial bacteria in the gut, significantly reduces this conversion.
Gallbladder and Liver Function
A sluggish gallbladder interferes with proper liver detoxification and prevents hormones from being cleared from the body. Hypothyroidism impairs gallbladder function by reducing bile flow.
The liver metabolizes hormones, filters toxins, and cleans the blood. Low thyroid function interferes with this process, making the liver and gallbladder sluggish and congested, and contributing to gallstones.
Thyroid hormones affect the liver cells responsible for detoxification most of all. When thyroid function is low, the enzymes that carry out the detoxifying tasks don't function properly.
The thyroid gland produces and stores calcitonin, a calcium-regulating hormone. Hypothyroidism prevents the ends of the long bones from forming fully or correctly.
Insulin and Glucose Metabolism
People with low thyroid function absorb glucose more slowly than normal and their cells don't use its energy as readily.
Estrogen and Progesterone Metabolism
Estrogen must first be made water soluble in the liver in order to be eliminated from the body. During this process, estradiol is formed, a secondary type of estrogen. Hypothyroidism may hinder pathways in the liver that make this possible, leading to estrogen dominance and breast cancer, uterine fibroids, ovarian cysts.
Thyroid hormones sensitize the body's cells to progesterone, so that they are able to readily take it up when needed. When the cell's progesterone receptor sites are not exposed to enough thyroid hormones, they lose the ability to allow progesterone into the cells.
You've probably experienced the frustrating, overweight symptom first hand, if you suffer from hypothyroidism. This simply slows down the body's metabolism and fat burning. Adrenal hormones that enhance fat burning are not efficient anymore and the sites on the cells that respond to lipase, an enzyme that metabolizes fat, are shut down.
Cholesterol is the backbone of all steroidal hormones. The cellular uptake of LDL cholesterol will diminish if there is inadequate thyroid hormone in the cells. Consequently, LDL levels in serum may rise significantly due to poor LDL utilization. When a person's thyroid is functioning below normal, he/she makes fat much more quickly than it's burned, which drives up triglycerides and LDL cholesterol.
As you see, the health of your thyroid is too important not to choose an integrative approach to healing, where all aspects of your metabolism are taken into consideration.