Thyroid Resources Community Group
We are sharing here the results of our research. Much of it is evidence-based.
One of the questions asked most frequently by hypothyroid patients is: "Does a low TSH mean I shouldn't get an increase in my medication?"
I'm going to attempt to answer your questions about that in a series of posts on this thread.
This post addresses the question: "If you have a low TSH, you’ll get osteoporosis and/or low calcium.”
The thyroid-gland is not the master-controller of calcium levels. The parathyroid glands control calcium levels via PTH. The parathyroid glands have NOTHING to do with the thyroid gland other than they're located NEAR the thyroid gland.
http://www.jonbarron.org/article/endocrine-system-thyroid-and-parathyroid-gland#sthash.XwjnwXAR.dpuf
So why do doctors get so confused about this? Well, C-Cells are often referred to as "c-cells of the thyroid" or parafallicular cells. So, in essence, the thyroid does produce calcitonin but not in response to TSH. How do we know this?
C-cells are indeed IN the thyroid gland (but in the connective tissue surrounding it). It DOES produce calcitonin, but here's the thing to remember:
"Calcitonin inhibits bone resorption by blocking the parathyroid hormone (PTH)-receptors on the osteoclasts....Calcitonin deficiency does not lead to hypercalcaemia, and excess calcitonin from tumours does not lead to hypocalcaemia. Therefore, most effects of calcitonin are evidently offset by appropriate regulation through the actions of PTH and vitamin D.
Calcitonin in plasma declines with age and is lower in women than in men. Low levels of calcitonin are involved in accelerated bone loss with age and after menopause (osteoporosis)."
http://www.zuniv.net/physiology/book/chapter28.html#6. Calcitonin
Calcitonin is not related to TSH in any way.
More on that:
"An additional hormone produced by the thyroid contributes to the regulation of blood calcium levels. Parafollicular cells produce calcitonin in response to hypercalcemia. Calcitonin stimulates movement of calcium into bone, in opposition to the effects of parathyroid hormone (PTH). However, calcitonin seems far less essential than PTH, as calcium metabolism remains clinically normal after removal of the thyroid (thyroidectomy), but not the parathyroids."
http://en.wikipedia.org/wiki/Thyroid
Again: "However, calcitonin seems far less essential than PTH, as calcium metabolism remains clinically normal after removal of the thyroid (thyroidectomy), but not the parathyroids."
Which is WHY calcitonin has nothing to do with TSH.
While in a healthy thyroid the TSH controls the thyroid. TSH does NOT control the parathyroid glands. PTH does. What does the parathyroid gland have to do with TSH? Even less it turns out...
The parathyroid glands respond to calcium levels in the blood - (which is why our creator put them near the rich blood sources in our necks) - if they detect low calcium levels - they send a signal saying "Hey, we need more calcium". Same with phosphorus. It acts as an antagonist to calcitonin.
TSH plays NO part in this. NONE. TSH only regulates the thyroid - that's it - and ONLY if the thyroid is HEALTHY (meaning no thyroid replacement meds are being taken).
Here's more on that:
http://www.parathyroid.com/parathyroid-function.htm
http://www.parathyroid.com/parathyroid.htm
"Parathyroid Disorders
Most people have four pea-sized glands, called parathyroid glands, on the thyroid gland in the neck. Though their names are similar, the thyroid and parathyroid glands are completely different. The parathyroid glands make parathyroid hormone (PTH), which helps your body keep the right balance of calcium and phosphorous.
If your parathyroid glands make too much or too little hormone, it disrupts this balance. If they secrete extra PTH, you have hyperparathyroidism, and your blood calcium rises. In many cases, a benign tumor on a parathyroid gland makes it overactive. Or, the extra hormones can come from enlarged parathyroid glands. Very rarely, the cause is cancer.
If you do not have enough PTH, you have hypoparathyroidism. Your blood will have too little calcium and too much phosphorous. Causes include injury to the glands, endocrine disorders or genetic conditions. Treatment is aimed at restoring the balance of calcium and phosphorous."
http://www.sacent.com/condition-thyroid-parathyroid-sacramento-ent-ca.html
"The blood calcium level is the main stimulus for the release of these hormones, as the release of these hormones is not controlled by the pituitary."
See more here:
http://www.patient.co.uk/health/the-thyroid-and-parathyroid-glands
How they work:
http://www.patient.co.uk/health/the-thyroid-and-parathyroid-glands
http://www.wisegeek.com/what-is-the-connection-between-calcitonin-and-pth.htm
It's not so confusing if you remember:
Parathyroid (PTH) gets rid of Ca2+ from the bones and sends it to the bloodstream.
Calcitonin will tone up the bones by depositing Ca2+ from the bloodstream into the bones.
http://wiki.answers.com/Q/Where_are_calcitonin_hormones_produced#slide2
If a problem with the parathyroid hormones are suspected a PTH NOT a TSH test should be performed along with calcium level tests.
Now, the BIG questions for thyroid patients (well, mostly their doctors) is: Will a low TSH damage my bones and give me osteoporosis? No, but having a low PTH might. The reason I say "might" is that calcitonin is poorly understood. Most of the studies done on women and bone health have more to do with sex hormones than thyroid hormones or, conversely, they look ONLY at thyroid/parathyroid hormones and leave out sex hormones.
Here's the big question: Why do women (almost exclusively) suffer from osteoporosis when men do not? Even when both sets of study subjects have hypothyroidism? So far, it hasn't been answered conclusively. But, more studies have been done on sex hormones (and lack of them).
This study is a good representation of that dichotomy:
http://www.thyroidresearchjournal.com/content/6/1/11
More on that: http://www.intechopen.com/download/get/type/pdfs/id/29569
And that's it for TSH, parathyroid glands, and bone density for now!
Bonus: GREAT article by vets: https://s3.amazonaws.com/assets.prod.vetlearn.com/3a/b3d1f0542211e19900005056ad4735/file/VT0312_Liss_CE.pdf
I'm going to attempt to answer your questions about that in a series of posts on this thread.
This post addresses the question: "If you have a low TSH, you’ll get osteoporosis and/or low calcium.”
The thyroid-gland is not the master-controller of calcium levels. The parathyroid glands control calcium levels via PTH. The parathyroid glands have NOTHING to do with the thyroid gland other than they're located NEAR the thyroid gland.
http://www.jonbarron.org/article/endocrine-system-thyroid-and-parathyroid-gland#sthash.XwjnwXAR.dpuf
So why do doctors get so confused about this? Well, C-Cells are often referred to as "c-cells of the thyroid" or parafallicular cells. So, in essence, the thyroid does produce calcitonin but not in response to TSH. How do we know this?
C-cells are indeed IN the thyroid gland (but in the connective tissue surrounding it). It DOES produce calcitonin, but here's the thing to remember:
"Calcitonin inhibits bone resorption by blocking the parathyroid hormone (PTH)-receptors on the osteoclasts....Calcitonin deficiency does not lead to hypercalcaemia, and excess calcitonin from tumours does not lead to hypocalcaemia. Therefore, most effects of calcitonin are evidently offset by appropriate regulation through the actions of PTH and vitamin D.
Calcitonin in plasma declines with age and is lower in women than in men. Low levels of calcitonin are involved in accelerated bone loss with age and after menopause (osteoporosis)."
http://www.zuniv.net/physiology/book/chapter28.html#6. Calcitonin
Calcitonin is not related to TSH in any way.
More on that:
"An additional hormone produced by the thyroid contributes to the regulation of blood calcium levels. Parafollicular cells produce calcitonin in response to hypercalcemia. Calcitonin stimulates movement of calcium into bone, in opposition to the effects of parathyroid hormone (PTH). However, calcitonin seems far less essential than PTH, as calcium metabolism remains clinically normal after removal of the thyroid (thyroidectomy), but not the parathyroids."
http://en.wikipedia.org/wiki/Thyroid
Again: "However, calcitonin seems far less essential than PTH, as calcium metabolism remains clinically normal after removal of the thyroid (thyroidectomy), but not the parathyroids."
Which is WHY calcitonin has nothing to do with TSH.
While in a healthy thyroid the TSH controls the thyroid. TSH does NOT control the parathyroid glands. PTH does. What does the parathyroid gland have to do with TSH? Even less it turns out...
The parathyroid glands respond to calcium levels in the blood - (which is why our creator put them near the rich blood sources in our necks) - if they detect low calcium levels - they send a signal saying "Hey, we need more calcium". Same with phosphorus. It acts as an antagonist to calcitonin.
TSH plays NO part in this. NONE. TSH only regulates the thyroid - that's it - and ONLY if the thyroid is HEALTHY (meaning no thyroid replacement meds are being taken).
Here's more on that:
http://www.parathyroid.com/parathyroid-function.htm
http://www.parathyroid.com/parathyroid.htm
"Parathyroid Disorders
Most people have four pea-sized glands, called parathyroid glands, on the thyroid gland in the neck. Though their names are similar, the thyroid and parathyroid glands are completely different. The parathyroid glands make parathyroid hormone (PTH), which helps your body keep the right balance of calcium and phosphorous.
If your parathyroid glands make too much or too little hormone, it disrupts this balance. If they secrete extra PTH, you have hyperparathyroidism, and your blood calcium rises. In many cases, a benign tumor on a parathyroid gland makes it overactive. Or, the extra hormones can come from enlarged parathyroid glands. Very rarely, the cause is cancer.
If you do not have enough PTH, you have hypoparathyroidism. Your blood will have too little calcium and too much phosphorous. Causes include injury to the glands, endocrine disorders or genetic conditions. Treatment is aimed at restoring the balance of calcium and phosphorous."
http://www.sacent.com/condition-thyroid-parathyroid-sacramento-ent-ca.html
"The blood calcium level is the main stimulus for the release of these hormones, as the release of these hormones is not controlled by the pituitary."
See more here:
http://www.patient.co.uk/health/the-thyroid-and-parathyroid-glands
How they work:
http://www.patient.co.uk/health/the-thyroid-and-parathyroid-glands
http://www.wisegeek.com/what-is-the-connection-between-calcitonin-and-pth.htm
It's not so confusing if you remember:
Parathyroid (PTH) gets rid of Ca2+ from the bones and sends it to the bloodstream.
Calcitonin will tone up the bones by depositing Ca2+ from the bloodstream into the bones.
http://wiki.answers.com/Q/Where_are_calcitonin_hormones_produced#slide2
If a problem with the parathyroid hormones are suspected a PTH NOT a TSH test should be performed along with calcium level tests.
Now, the BIG questions for thyroid patients (well, mostly their doctors) is: Will a low TSH damage my bones and give me osteoporosis? No, but having a low PTH might. The reason I say "might" is that calcitonin is poorly understood. Most of the studies done on women and bone health have more to do with sex hormones than thyroid hormones or, conversely, they look ONLY at thyroid/parathyroid hormones and leave out sex hormones.
Here's the big question: Why do women (almost exclusively) suffer from osteoporosis when men do not? Even when both sets of study subjects have hypothyroidism? So far, it hasn't been answered conclusively. But, more studies have been done on sex hormones (and lack of them).
This study is a good representation of that dichotomy:
http://www.thyroidresearchjournal.com/content/6/1/11
More on that: http://www.intechopen.com/download/get/type/pdfs/id/29569
And that's it for TSH, parathyroid glands, and bone density for now!
Bonus: GREAT article by vets: https://s3.amazonaws.com/assets.prod.vetlearn.com/3a/b3d1f0542211e19900005056ad4735/file/VT0312_Liss_CE.pdf
http://www.bioidenticalhormones101.com/Natural_Thyroid_Better2.html
http://tiredthyroid.com/tsh.html