Newton also believed, that the taboo to not eat blood among some christians derives from the fact that earlier there was a total ban of eating meat in christianity.

I think there is some proof to think Newton would be a vegetarian. For instance, he believed that all the worlds religions were vegetarian before, and that the three laws for the first religion were (he believed world had had one religion in the past, from which all the religions had developed): respect/treat well your God, other people and animals. Today Christianity has only the first two.

More info from the book "The Bloodless Revolution" (I highly recommend):

www.wwnorton.com/catalog/fall06/005220.htm

I found in the following website
www.ivu.org/history/renaissance/newton.html that
There has long been a rumor that Newton was vegetarian, although none of his biographies mention anything on the subject, so I wrote to his biographers to see if there was anything in the primary sources. I received this reply from Dr. Patricia Fara, a Newton scholar at Cambridge University: "I have heard the rumour, but the evidence suggests that he did eat meat except for the last five years of his life, when he was quite frail and followed a light diet which might perhaps have been vegetarian."
I have received the following note from the American Newton scholar Gale Christianson: "Newton did tend to eat vegetables and broth when he was an old man, but there is nothing to indicate that he was a conscious vegetarian...during the early and middle years."
Finally, James Gleick, the famous writer of 'Chaos' recently wrote a book about Newton. I asked him if he knew of the long-held rumor that he was vegetarian. He replied, "The 'rumor' started with his niece, who said he was reluctant to eat meat in later life. It's just one data point. Hardly anything is known about what he ate except that he didn't care much about meals."

So, it means that including Sir Isaac Newton's name in the group of vegetarians is not correct. I wish to know the truth