Scientists at the University of Texas MD Anderson Cancer Centre have discovered that women with an underactive thyroid or hypothyroidism, develop less breast cancers.
Dr Massimo Cristofanilli’s team compared the medical records of 1,136 women with breast cancer and 1,088 healthy women to find that women with an underactive thyroid had a 61 per cent lower risk of developing invasive breast cancer (1). Because it looked at past data, this is called an Observational Study.
Where there were breast cancer patients who also had a history of hypothyroidism, they tended to be older on diagnosis and have a less aggressive, indolent variety of the disease that was ER+ve.
One of the main causes of an underactive thyroid is low iodine (2). Adding just a little sea kelp or sea moss into your diet or a green juice should overcome the low iodine issue. Another influence is a poor microbiome. Of course, there is a chance you could have a thyroid problem but before taking Levothyroxin you should be aware of your iodine levels.
Equally, there are now multiple research studies that synthetic thyroid hormone can stimulate breast cancer via a parallel pathway to oestrogen.
*****
References
1. University Of Texas M. D. Anderson Cancer Center. "Hypothyroidism Associated With Reduced Breast Cancer Risk." ScienceDaily. ScienceDaily, 16 February 2005. .
2. Synthetic thyroid hormone, iodine and breast cancer - https://www.canceractive.com/article/is-the-synthetic-thyroid-hormone-thyroxine-behind-your-cancer