Ohnuma And Eucharist Comparison

I see a lot of similarities between the Christian tradition of Eucharist and the body of the Buddha/bodhisattva, particularly in the relationship the bodies of Jesus and the Buddha have with their followers. Both become some sort of food sustenance for their disciples – Jesus as bread, initially at the last supper and then when this is later embodied in the tradition of the Eucharist, and Buddha as King Padmaka in the form of a rohita fish, and King Sudolagarne, also as a fish.
Both also made their initial offering of their bodies to their devoted disciples. As Ohnuma states in “The Gift of the Body,” the “good group of five... are celebrated… as the first to taste the food of the dharma” (p. 334). They also mirror each other in that the bodhisattva’s
“Thus, I would argue that the Buddha's gift of dharma is not only concretized but also given the emotional weight it truly demands when it is symbolized by the bodhisattva's miraculous and unbelievable deed of sacrificing his own body” (p. 357). This does make sense, but I’m also confused by it because of our talks about the body being impure. I understand the people ate the body of the king/fish because he gave himself as a sacrifice, but does this mean his body is not contaminated? Was his vow to save the people and feed them with his body enough to purify it, or is it already pure because the king(s) was a previous incarnation of the Buddha – even if the people who ate the body at the time did not know that he was an incarnation of the Buddha?
Perhaps it is that his body as a fish does not contain the impurities of his human body, and that is why it was proper to eat, but there is still nonetheless some essence of humanity in that fish. We’ve encountered many stories of the body as food for other humans in our readings, but we’ve also learned that the human body is dirty and impure, so I’m curious as to whether these exceptions are tied to the fact that they are the Buddha’s