The gene that may prevent Alzheimer's dementia 15-09-2008 A gene called ‘Selective Alzheimer’s disease indicator- (seladin-1) has been found in-vitro which means in the test tube to protect against beta-amyloid the substance that is intimately associated with the development of Alzheimer’s dementia.  So far it is known that thyroid hormone and specifically triiodothyronine or T3 which is the biologically active form of thyroid hormone and oestrogen have the power to turn on seladin-1.  This means that T3 status and for women the presence of oestrogen needs to be optimised.  To make T3 from T4, zinc, selenium and iodine are needed.  As deficiencies of these nutrients are commonplace assessing whether they are present in sufficiency with your physician is mandatory.  While the assessment of selenium status is difficult a 24-hour urine test for zinc and a 24-hour urine challenge test for iodine is a useful way to assess these minerals.