Acts 15 settled the question of how gentile and Jewish christians could enjoy unity and fellowship by requiring only the 'necessary things' that were required of temporary residents in Israel in the OT period.
These can be summed up as idolatry, fornication and blood.
A foreigner might cause outrage in Israel by using his portable idols, engaging in forbidden sexual practices - including marriages that were forbidden - and by eating unbled food. Other matters such as theft and murder were not mentioned since they were proscribed by Jew and gentile alike. As long as gentile christians observed these necessary things there need be no barrier to fellowship.
The law on blood was more significant than a dietary restriction. Blood was a symbol of a life that had been taken by another human. If an animal was found already dead it could be eaten unbled with impunity. Since no life is taken to donate blood it has no sacred value.
Please see The Watchtower are Right About Blood... for more detail.