Genetics. We learned about this defect when he became toxic after two days of selenium. Thanks to Newport for sorting this out for us. There is also an enormous need for thiamin (B1), to forestall what's known as alcohol dementia. Thanks to DH's mother, who just died of it. On DH's maternal side, everybody ends up demented. They live long and die awful. DH is 64. I'm fighting like heck to be his ace in the hole.