My hypothyroidism was getting worse and in desperation I searched PubMed for a non-absorbable lipid with affinity for PBDEs that could be safely ingested. I came across a study in which polydimethylsiloxane is used in sorption tubes for air sampling of PBDEs, it has an extraordinary capacity to capture minute traces of PBDEs, as low as 6 picogrammes per cubic metre: –

Searching for other forms of polydimethylsiloxane I came across Simeticone which is used as an antifoaming agent in endoscopy: –

Simeticone = Polydimethylsiloxane + silica gel

Simeticone is marketed as relief for trapped wind: –

Simeticone in the UK. All brands are equally effective.

It seems a bit weird but logically simeticone should reduce the PBDE burden, so I trialled the recommended dose of up to 4 x 0.125g daily hoping for a small improvement. This dose is very small compared to 10g olestra. After eight weeks, I experience mild breathlessness when warming up for badminton, I went home and checked my heart rate with a sphygmomanometer. It was very erratic, so I went to my GP who sent me to the local hospital where I was admitted to Resus with supraventricular tachycardia (SVT) which fortunately reverted with IV magnesium and a Valsalva manoeuvre. My liothyronine requirement had reduced very dramatically. My hypothyroid symptoms resolved completely. After reducing my liothyronine dose to 20 mcg I eventually settled on 40 mcg daily. If I don’t take any thyroid hormone, I feel tired and have a poor working memory and ability to concentrate. I believe this is because my TSH was suppressed for over a decade and this has down-regulated my hypothalamic pituitary thyroid axis leading the consequences of Subnormal TSH Secretion.

The instructions for simeticone products caution that it may reduce the absorption of thyroid medications. This is good news! It confirms that simeticone blocks the absorption (or reabsorption) of thyroid hormone like products. You should take simeticone a few hours away from your thyroid hormone.

IMPORTANT: Lowering my PBDE burden led to a sudden reduction in my hormone requirement, which is not gradual or predictable. If you are on supraphysiological doses of thyroid hormone, say > 150 mcg levothyroxine or > 40 mcg liothyronine then you must monitor your status daily, including your pulse and be prepared to reduce your dose substantially.

A Bit of Trivial Evidence

A highly specific sign of hypothyroidism is slow tendon reflexes. I have played badminton for many years, just for exercise. I was never able to hit the shuttle from one end of the court to the other, it doesn’t need strength, just a snap of the arm to deliver speed. After my SVT episode I suddenly found the shuttle was travelling the full length of the court. My reflexes had speeded up. I never expected this. A consequence was that after a few weeks I developed tennis elbow, or rather painful triceps! I’d never had this, my muscles were not used to fast contractions.

I suspect ARTH is the prime source of brain fog.