Majority of religion discourage eating blood(cooked of-course). However I have come across sections of people?

Well, blood in general is high in iron, if I recall. However, the only type of 'cooked' blood product that I know people eat is blood sausage, and that is by European cultures, such as German, Italian, and English people. I do not know of any religions that discourage eating blood products. On a more personal note, I can not eat it because I know what black pudding is made of, and it does not appeal at all, but most of my friends are Scottish, and they enjoy it.