There is another argument that says that the geography of the Middle East is particularly unsuitable for pigs and much more suitable for sheep, goats, and cows. Pigs are designed for living in forests, outside of forests then are a significant drain on resources.

Cows, sheep and goats are grazers and are much more suitable for semi-nomadic people. They are capable of eating grass, from which humans cannot gain sustenance. For ecological reasons it would make sense for Semitic peoples living in the Middle East not to eat pigs. For people living in large sections of China, South East Asia, and Europe, eating pigs is much more environmentally sustainable - assuming you are hunting them in the forests rather than intensively rearing them in sheds.

There is one other reason I have heard for not eating pork is that it is difficult to distinguish from human flesh. It could well be that this prohibition developed to avoid cannibalism or because people found the whole idea of eating something that looked so similar to human flesh ... distasteful.

However, it should be noted that the Torah and Koran makes no such health claims for the reasoning on these rules.

Different sects within Islam may well have different customs regarding pigs, with some shunning all products from pigs. This is almost certainly a long held tradition amongst groups of Muslims and does not need to come directly from the Koran. Father Christmas, Lent, and Purgatory are not mentioned in the bible, but that does not mean that groups of Christians have not incorporated the ideas into Christianity.