Apologies for having a one-track mind currently but yes I’m still banging on about the thyroid this week.  You see, this year in my own clinic I connected up some dots I hadn’t connected before via a series of young female patients.  Each of these women presented with some hypothyroid features, most notably, low basal body temperatures, fatigue and weight gain and while their thyroid hormones (TSH, T4 and T3) were all technically ‘within range’, their T3 levels were very low (low 3s) and the TSH seemed to sit low as well (<1.5).  Normally of course, when T3 levels drop we expect TSH secretion from the pituitary to rise in response, as a means to correcting this dip, however, this part of regulation appeared ‘blunted’ or even ‘broken’ in these women.

So why would their pituitary be sleeping on the job, allowing them effectively to experience long term suboptimal thyroid function?

Going over the medical history of each woman, I realised they had something else in common, each experiencing anorexia nervosa as a teenager.  Many of us know that during anorexia thyroid function adopts a ‘hibernation response’, slowing right down to prevent further catabolism etc. but often we’re told that upon re-feeding and achieving normal weight, this adaptation will resolve.

New research is emerging however to suggest that while thyroid function does improves to some extent with weight gain, it may take a much longer time to completely normalise – if at all.

Think this only relates to your patients who’ve suffered anorexia nervosa…think again!  The same thyroid maladaptation can be seen in many patients who have been through a protracted period of restricted eating e.g. fad diets, and in particular is most potently induced in a low carbohydrate dietary context which is where I’m also seeing it present in some of my patients.  This is really big news as far as I’m concerned, because it explains this ‘sleeping thyroid’ I’ve been seeing and helps me to understand how to treat it, which is via a combination of pituitary and thyroid jumper leads!  Want to learn more about low T3 syndrome, the mechanisms behind it and how to manage this in your patients? Check out the latest Premium Audio download on the topic where I talk you through it all in more detail, illustrated with a great case summary https://rachelarthur.com.au/product-category/premium-audio/