Iodine, goiter and thyroid problems of Galapagos tortoises

Bee62

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When Galapagos tortoises are kept in captivity it is important to ensure that these tortoises have enough intake of iodine with their food or water.
Why ?
These tortoises live on an island midst the ocean. Ocean water always contains traces of iodine.
Iodine is important and nesessary for the thyroid to produce hormone.
When there is a lack of iodine for many years the thyroid begins to grow. You can see this, it is called a goiter. Animals and humans can get a goiter. It is caused from the lack of iodine.
But the hormone of the thyroid are nesessary for the whole body. They control heart, liver, kidney function and more.
When a sick ( bigger grown ) thyroid cannot produce these hormone any longer the whole body gets sick. A goiter is always a sign for a severe sickness !
Even some food like kale is known to disturb the intake of iodine in the body.
What can we do ?
Please make sure your galop tortoise gets enough iodine with the food or water. Iodine pills are cheap and they are small. You can add an iodine pill from time to time to the soaking water when your galop is still small or give it with some food. Only with a healthy thyroid the tortoise can be healthy.
Unfortunately galapagos and aldabra tortoises often suffer a lack of iodine and as a result a malfunction of the thyroid.

For more informations about the function of the thyroid please read here:
https://en.wikipedia.org/wiki/Thyroid
https://en.wikipedia.org/wiki/Goitrogen
https://www.thetortoisetable.org.uk/plant-database/viewplants/?plant=621&c=8
Please click on "goitrogens" in the article about kale ( on tortoise table ). There it is explained what goitrogens can cause.

I am wishing your giant tortoise a happy, healthy long life.
 
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Bee62

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Thank you, Sabine.
When you think it is helpful, please pin the thread on top of the Galapagos tortoise subforum. Maybe the same with the thread for the Aldabra tortoises there too. I think all owners of Aldabra and Galapagos tortoises should know about the problems that a lack of iodine can cause.
 

Tom

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Sabine, there is a whole group over here studying this phenomenon in the Galapagos tortoises and we get updates annually at the TTPG.

These are not goiters and they are not related to iodine intake or the thyroid. They really aren't sure what causes it, but they are drawing blood from every captive Galop they can find and comparing and contrasting every parameter from the ones that get the "goiters" and the ones that don't. So far, this remains a medical mystery.

I also thought it would be related to iodine and how close to the coast they live. I grew up 3 miles form the beach and learned that after about 50 miles inland, the iodine from the salt spray peters out and dietary iodine becomes necessary. Many Galops that are close to the coast get these swellings, and some of the inland ones 100's of miles from any coast don't get them.

Another person following this hunch started feeding seaweed to their tortoise that had one of these swellings. Amazingly, the swelling completely receded and the tortoise went back to normal... for about two months, and then the swelling came back and stayed even with lots more seaweed added to the diet along with iodine supplementation.

Another odd thing I've heard is that if they haven't gotten one of these swellings by the age of 11 years old, they never will. The person telling me was convinced of it.

More study is needed, and we will eventually figure this thing out, but your info source for this is incorrect.
 

mark1

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it's pretty old , but a pretty good story about a hypothyroid Galapagos tortoise , they did save this girl ……… you have to wonder if chronic stress could not have been responsible for this tortoises hypothyroidism ? she was one of five in a group kept together ……. dogs can acquire immune mediated thyroiditis which results in hypothyroidism ……..

https://www.researchgate.net/profil...ochelone-elephantopus-with-Hypothyroidism.pdf
 

Bee62

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Sabine, there is a whole group over here studying this phenomenon in the Galapagos tortoises and we get updates annually at the TTPG.

These are not goiters and they are not related to iodine intake or the thyroid. They really aren't sure what causes it, but they are drawing blood from every captive Galop they can find and comparing and contrasting every parameter from the ones that get the "goiters" and the ones that don't. So far, this remains a medical mystery.

I also thought it would be related to iodine and how close to the coast they live. I grew up 3 miles form the beach and learned that after about 50 miles inland, the iodine from the salt spray peters out and dietary iodine becomes necessary. Many Galops that are close to the coast get these swellings, and some of the inland ones 100's of miles from any coast don't get them.

Another person following this hunch started feeding seaweed to their tortoise that had one of these swellings. Amazingly, the swelling completely receded and the tortoise went back to normal... for about two months, and then the swelling came back and stayed even with lots more seaweed added to the diet along with iodine supplementation.

Another odd thing I've heard is that if they haven't gotten one of these swellings by the age of 11 years old, they never will. The person telling me was convinced of it.

More study is needed, and we will eventually figure this thing out, but your info source for this is incorrect.
Hi Tom. When you can see a "swelling" on a tortoises neck the thyroid is already damaged and don`t work properly. That means the thyroid produces too less or no hormone. In this case the tortoise needs no iodine but hormone. Iodine is to prevent a malfunction of the thyroid and the building "goiter" as a visible sign of it. When the thyroid is not working any more no iodine can help.
The food a tortoise gets is also important. When a tortoise is feed with much kale the intake of iodine can be badly disturbed. Kale contents goitrogenes.
That can be the reason why some galapagos tortoises that are living near the ocean get a sick thyroid and others not.
The function of a thyroid and the building of the 2 thyroid hormone is complicated and depends on many different and infuencing factors. But that iodine is needed to keep a thyroid working properly is a fact.
 

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Nobody truly understands what triggers thyroid problems. As a sufferer of Graves Disease myself I have been there with an over-active thyroid and that is what produces the goiter in the throat. The thyroid is producing too much thyroxin when a goiter is present. Over active thyroid can be treated in humans and I was lucky that "block and replace" therapy worked for me. Some people end up drinking radioactive iodine to kill off part of the thyroid.

An underactive thyroid doesn't produce a goiter usually. Unfortunately, it looks like I am heading that way. I was warned that I was at higher risk having had Graves Disease in the past.
 

Tom

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Hi Tom. When you can see a "swelling" on a tortoises neck the thyroid is already damaged and don`t work properly. That means the thyroid produces too less or no hormone. In this case the tortoise needs no iodine but hormone. Iodine is to prevent a malfunction of the thyroid and the building "goiter" as a visible sign of it. When the thyroid is not working any more no iodine can help.
The food a tortoise gets is also important. When a tortoise is feed with much kale the intake of iodine can be badly disturbed. Kale contents goitrogenes.
That can be the reason why some galapagos tortoises that are living near the ocean get a sick thyroid and others not.
The function of a thyroid and the building of the 2 thyroid hormone is complicated and depends on many different and infuencing factors. But that iodine is needed to keep a thyroid working properly is a fact.
All of that makes sense as far as a discussion about thyroid function, goiters and iodine, but what I am telling you is that these swelling in Galapagos tortoises are not related to thyroid, iodine and goiters. It is something else.

They've been trying to eliminate variables and so far it appears diet, and proximity to the coast are not factors. In many herds of several galops, one or two will get the swellings and the rest don't while all live in the same place and eat the same foods.

We don't know yet what this is, what causes it or how to prevent it, but we've eliminated a lot of the possibilities so far. Its not related to iodine or diet and it is not goiters.
 

Bee62

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All of that makes sense as far as a discussion about thyroid function, goiters and iodine, but what I am telling you is that these swelling in Galapagos tortoises are not related to thyroid, iodine and goiters. It is something else.

They've been trying to eliminate variables and so far it appears diet, and proximity to the coast are not factors. In many herds of several galops, one or two will get the swellings and the rest don't while all live in the same place and eat the same foods.

We don't know yet what this is, what causes it or how to prevent it, but we've eliminated a lot of the possibilities so far. Its not related to iodine or diet and it is not goiters.
Tom, and what do you think about this thread and the treatment of the tortoise now ?
https://www.tortoiseforum.org/threads/sick-galapagos-tortoise.171912/page-6#post-1696684
 

mark1

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my ex wife had graves disease , they destroyed her thyroid with radiation/iodine and replaced the hormone with pills , that was 15-20yrs ago , it seems to have worked well …… a goiter I believe is just an enlargement/hyperplasia of the thyroid , indicating there is a problem ….. hypothyroidism is a common cause of goiter ….. used to be iodine deficiency , just not anymore , at least not in America ……. thyroiditis can be caused by a virus , bacteria , drugs , toxins , or their own immune response , it appears to be genetic in dogs …. if your thyroid is not functioning iodine won't help …….. I believe too much iodine can cause goiter ……….. goiter is pretty well documented in Galapagos tortoises , I've seen a lot of literature on it …… I seen Bee62 mention diet , goitrogenic foods , is soy and beets goitrogenic ? I believe they are a major ingredient in mazuri ?
 

mark1

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Goiter, goitrogens, and thyroid enlargement
https://drknews.com/goiter-goitrogens-and-thyroid-enlargement/

Many people assume any enlargement of the thyroid gland is a goiter and indicates an iodine deficiency. Nothing is further from the truth and I would like to clarify the information.
........Enlargement of the thyroid gland is classified as diffuse if the entire thyroid gland is enlarged or solitary if only a small section of the thyroid is enlarged. The most common causes of solitary enlargements are benign cysts and nodules. However, a nodule should always be evaluated to make sure it is not a malignant growth found with thyroid cancer. Now let’s talk about diffuse enlargement. This means the entire gland has become enlarged. The two main causes of diffuse enlargement are goiter or swelling from thyroiditis (inflammation of thyroid gland). Diffuse enlargements are rarely found with thyroid cancer
 

mark1

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the first pdf I posted was a 300lb adult raised in north Dakota , his growth rate and age was unknown …….. the pdf in this post are five 3-4yr olds , they weigh from 22-81lbs ……. I believe a 3-4 yr old wild Galapagos tortoise weighs something like 2-3lbs , which is a phenomenal increase in growth rate , makes me think of "olddog's" post on growth rates and problems associated with excessive growth , I think growth and I think of pituitary , pituitary makes you think thyroid …………according to the WHO , sudan is/was an endemic area for iodine deficiencies in people , makes you think environmental iodine is scarce , you'd think iodine deficiency would be represented in some of the wildlife , like the sulcata's ……

https://www.researchgate.net/public...Subadult_Galapagos_Tortoises_Geochelone_nigra

https://www.researchgate.net/public...Subadult_Galapagos_Tortoises_Geochelone_nigra
 
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