levo and cancer?

[lauriegraham]

i wonder if people have seen this and what they think? paulrobinsonthyroid.com/new...

[Lalatoot]

The sentence that stands out in this for me is:" I would think that the people in the higher risk category are those with low levels of FT3, or high levels of reverse T3,"

Paul Robinson is only thinking. He goes on to use the words " My belief". This is not someone who has researched and found several undeniable research papers. He is not stating provable facts only his thoughts. Too many times he uses words to imply that these are his ideas and suppositions rather than backed by studies.

Also I wonder about his thought on cancer being caused by high levels of rT3. rT3 can be caused by many factors only one of which is related to thyroid.

[Jazzw]

It’s something I’ve read about in the past and therefore something to which I’ve also given some thought.

And my thoughts go thus:

Thyroid hormone is needed by every cell in the body. Every cell in the body is constantly being replaced. Cancer (very broadly) happens because of abnormalities in cell reproduction.

If there’s a correlation between cancer and levothyroxine, it’s likely to be caused by someone being undiagnosed for a long time (how often do we see that!) and then potentially under-replaced (left on too low a dosage of levothyroxine—again, how often do we see that?!), which could feasibly lead to a rise in cell replication abnormalities.

Those on liothyronine as well as levothyroxine are more likely to be people who’ve taken steps (or whose doctors have taken steps—a rarer scenario sadly) to optimise their thyroid hormone replacement dosage, which in turn leads to better cell replication.

Just my theory—but I’m always wary of correlation studies. Like the ones where they try to link bacon consumption to cancer, while blithely ignoring that most people don’t eat bacon on its own...

[helvella Administrator Thyroid UK]

That paper includes this sentence:

Although the major product of the thyroid is T4, most of it is converted to more biologically active T3 that binds to nuclear thyroid receptors and modulates the expression of proteins traditionally known to increase basal metabolic rate and enhance growth [3].

Which is wrong. Somewhere around one third of the T4 produced by a healthy thyroid gets converted to T3. Not "most".

[janeroar in reply to helvella]

Clever helvella!

[lauriegraham]

Very helpful responses, I agree completely with sceptisism re correlational studies

[helvella Administrator Thyroid UK]

Yes !

[radd]

🤣