Back in the early 1980’s I was, for a time, secretary to a local railway preservation group, one of whose members was a railway engineer. His wife, however, was a long-experienced SCM (state certified midwife) who worked in the maternity unit at the Royal Infirmary. She told me that for every White child born with a congenital physical or mental impediment, including Downs’ Syndrome, in her maternity unit, no fewer than 25 such infants were born to Muslim mothers!

It is therefore clear that whatever robust health the Muslims enjoy as result of their malodorous, one-flavour diet, is more than offset by the prevalence of defects in their heavily in-bred ( i.e. routine cousin-to-cousin marriage) genes.
This might perhaps also explain their abject failure to advance their society
either scientifically or socially, beyond its original, seventh-century condition.