Naruto had harnessed Kurama's chakra to become a godlike soldier. It's what helped him surpass Sage Mode, coming close to being a warrior akin to the Sage of the Six Paths. This allowed Naruto to fight off numerous aliens from the Ōtsutsuki clan.
Kurama messing with Naruto's physiology does make sense as these beasts are weapons of mass destruction. They pack nuclear power to destroy nations, and possibly worlds.
Kurama's Poisoning Could Tease Other Dangers