Thyroid Function and its Relationship with Estrogen and Progesterone

Thyroid is the hormone that regulates the metabolic rate. Low thyroid tends to cause low energy levels, cold intolerance and weight gain. Excess thyroid causes higher energy levels, feeling too warm and weight loss. The crucial nutrient for thyroid hormone synthesis is iodine. Once this was recognized iodides (salts of iodine) have been commonly added to table salts and these days iodine deficiency is rare. Iodine is also available in ocean fish and can be supplemented by taking kelp concentrate.

Estrogen, progesterone and thyroid hormones are interrelated. Estrogen for example, causes food calories to be stored as fat while thyroid hormones causes fat calories to be turned into usable energy. Thyroid hormone and estrogen therefore have opposing actions. Progesterone on the other hand increases the sensitivity of estrogen receptors for estrogen and at the proper levels, inhibits estrogen's negative side effects. This is what is meant in medical terms when it is said that estrogen opposes progesterone. The lack of progesterone in a women still making estrogen leads to the condition of unopposed estrogen.

Hormone balance involves a complete harmonious balance between all the hormones. The example is sometimes used of likening hormones with instruments in an orchestra so that when balanced and in harmony, the orchestra (or body) will perform as designed.

Dr. Lee has successfully treated patients diagnosed by other doctors with hyperthyroidism using natural progesterone therapy. Hyperthyroidism (excessive production of the thyroid gland) especially resulting from excessive L-thyroxin supplementation, accelerates bone resorbtion and thus promotes osteoporosis, presumably by stimulating osteoclast activity. Dr. Lee hypothesizes that estrogen dominance inhibits thyroid action in the cells by competing with the thyroid hormone at the site of it's receptor. He speculates that in so doing the thyroid may never complete it's mission, leading to hyperthyroid symptoms, even despite normal serum levels of thyroid hormones.

Another common thyroid dysfunction is Hashimoto's thyroiditis which is an autoimmune inflammatory process of the thyroid gland. This means that the body is creating antibodies against the cells which make up the thyroid gland. As this disease progresses, cells of the thyroid are destroyed and inflammation occurs along with fibrous deterioration of the entire gland.

It has been Dr. Lee's experience that when women with Hashimoto thyroiditis are given progesterone for osteoporosis, there results a gradual diminution of the severity of the decease and sometimes a complete resolution of the thyroiditis problem. He suggests that two factors might be at play that bring this result about:

1. Excess estrogen may have had a hand at triggering the antibodies and when estrogen dominance is corrected with progesterone, there is a gradual correction of the thyroid problem. Progesterone is the main precursor of corticosteriods and in progesterone deficient women, restoration of normal progesterone levels may lead to normal corticosteroid production, thus suppressing the autoimmune attacks.