He has only forbidden you carrion, blood and pork and what has been consecrated to other than Allah. But anyone who is forced to eat it – without desiring it or going to excess in it – commits no crime. Allah is Ever-Forgiving, Most Merciful. (Surat al-Baqara, 173)
The wisdom behind Allah’s prohibition of blood emerged during the 20th century. By carrying vitamins, hormones, oxygen and substances such as protein, sugar and fat absorbed during digestion to the cells, blood makes it possible for life to survive. On the other hand, it also carries various toxins and waste products that need to be expelled from the body. One of the most important tasks performed by blood is to transport substances such as urea, uric acid, keratin and carbon dioxide that need to be removed from the body.
What is more, blood is not a sterile environment; to put it another way, it is ideal for germs to grow in. i Since microbes have excellent opportunities to feed in blood, it represents an ideal environment for them. When in equilibrium with the functions of the other fluids in the body and the immune system, blood does not support micro-organisms, and therefore disease. In a healthy individual, these micro-organisms live by making use of one another inside the body. When that environment is seriously impaired, when the internal equilibrium is damaged, in other words, they may turn into micro-organisms that cause disease when they find the appropriate surroundings.
In addition to all this, blood is not suitable for use as a food product. The level of digestible proteins such as albumin, globulin and fibrinogen is low; just 8 grams in 100 ml. of blood. The same applies to fats. In addition, blood contains a high level of hemoglobin, a complex protein that is very difficult to digest and is unacceptable to the stomach. When blood clots, the protein fibrinogen gives rise to a plate containing erythrocytes (red blood corpuscles) by turning into fibrin. Fibrin is one of the hardest proteins to digest, thus making blood even more difficult to digest. In conclusion, health experts agree that blood is unfit for human consumption in any form.