Do you have any thoughts on how long it could take to get vitamin A back in a more appropriate range? (Assuming someone has eaten vitamin A in excess of what would be sufficient for their current thyroid condition for example, resulting in the suppression Ray spoke about)
Unless somebody has been taking large doses of vitamin A for weeks/months, then whatever thyroid suppressive effect may be there from vitamin A should dissipate rather quickly, probably within days after one stops intake. Just taking some vitamin E for a few days should be able to negate the anti-thyroid effects from peroxidized vitamin A right away. As far as the other claims of vitamin A toxicity as per Genereux - there should be a way to test for it, and we may be able to check levels in hair/nails, so if there is indeed vitamin A accumulation causing problems it should show up in those tests as they span a period of many weeks and even months. Also, if vitamin A is causing problems with bile that would/should manifest in elevated liver enzymes and possibly even bilirubin, which is easy to test for in blood.