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The Oestrogen-Thyroid Dance - how Oestrogen affects Thyroid health

The Endocrine system is our hormonal system and contains a beautiful interplay of a collection of organs and glands working harmoniously together…well that’s what should happen, but more often than not, dysfunction or an imbalance in any area here throws the whole interplay out.

The Endocrine system contains the pituitary and hypothalamus in the brain, the thyroid and parathyroid glands in the neck, the pancreas, adrenal glands and the gonads, or ovaries and testes, and the pineal gland.

Any dysfunction in any of the above glands will affect thyroid function, as all the hormones work synergistically together.

We know that hormonal fluxuations for especially women are key times where the thyroid can be triggered into dysfunction, such as puberty, pregnancy, peri-menopause and menopause. All these events have a common theme of oestrogen fluxuation.

So how does oestrogen affect thyroid health?

Oestrogen can impact the thyroid directly by affecting the sodium iodide symporter located in the thyroid tissue which regulates the uptake of iodine into the thyroid gland and sodium out. High levels of oestrogen block, and shuts down the symporter so iodine struggles to get into the thyroid gland cells needed to make thyroid hormones. This may result in hypothyroidism. TSH (thyroid stimulating hormone),from the pituitary gland, will rise as the thyroid gland does not have enough iodine to make its hormones T4 and T3.

Where does this excess oestrogen in the body come from?

The body may produce too much such as in oestrogen dominant conditions such as PCOS, fibroids and endometriosis. The oestrogen may come from synthetic forms such as the pill or HRT. Also, from environmental means such as xenoestrogens found in cosmetics and plastics. These xenoestrogens increase the bodies levels of oestrogen, play havoc with hormones ad increase cancer risk.

High levels of oestrogen increase thyroid binding globulin (TBG), which binds to the thyroid hormone T4 and pulls it out of use for the body to use. Low levels of T4 means a low conversion rate to T3, which lowers thyroid function.

The thyroid hormones T4 and T3 are transported around the body by TBG. The higher the TBG in response to oestrogen levels, the less free component of T4 and T3 are available to get into the cell. If the free part of these hormones cannot get into the bodies target cells, this may appear as “cellular hypothyroidism”. In cellular hypothyroidism, results look fine on blood tests as there seems to be enough thyroid hormones to go around, but most of the hormone is bound to TBG and can’t get into the cells so you may experience thyroid symptoms but your Doctor may will tell you that your thyroid is fine.

Declining levels of oestrogen such as experienced in Menopause can affect thyroid function also.

Some symptoms of menopause overlap with symptoms of an under-active thyroid: fatigue, problems with focus and memory, anxiety, and muscle pain.

The menopausal transition starts with menstrual cycles becoming longer. This changes the entire hormonal balance in the body, including the thyroid hormones. The thyroid becomes less able to produce the same amount of T4 and T3, while rT3 (reverse T3) levels increase. With age, the thyroid gland becomes flatter and has less output power. Less iodine is transported from the bloodstream and as a consequence the thyroid makes less T4. Also, the process of converting T4 to T3 takes longer too.

So even if a person never had any issues with their thyroid gland, they might start experiencing some thyroid-related symptoms in their older age.

How do I find out if my Oestrogen is high or low?

The best and most accurate way is through a urine test. Oestrogen is broken down in phase 1 liver detoxification and metabolised in phase 2 and then excreted out in the faeces and urine. An oestrogen urine test allows us to see how your oestrogen is being metabolised in the body …or not… Hormone blood tests only show what is in the blood stream and results may look normal when they are not.

How to support your Oestrogen levels

Supporting oestrogen metabolism, whether high or low will help balance thyroid function.

· Eating cruciferous greens, such as broccoli, broccoli sprouts, cauliflower, lightly steamed to eliminate their dietary goitrogen content, (another iodine blocker), aids the livers detoxification of oestrogen.

· Ensuring regular bowel movements as excess oestrogen is excreted in the bowels by consuming plenty of insoluble fibre, (nuts, beans, legumes, skins of fruits and vegetables, seeds, legumes.

· Drinking water helps to excrete excess oestrogen though urine.

· Eating organic as non-organic dairy and meat may contain hormones which will increase your oestrogen levels.

· Avoid exposure to xenoestrogens – plastics, cosmetics, OCP.

· Avoid soy as soy contains high levels of oestrogens and is a goitrogen which can block iodine uptake needed to make thyroid hormones.

· Manage your stress – during chronic stress, the body “steals” progesterone to make the stress hormone cortisol. Lower progesterone means higher levels of oestrogen.

Want more info on your hormone levels and thyroid health? Book a free discovery call today to discover how I can help you.


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