I want to give you a brief window into my life in this little corner of journalistic endeavor. Ready? Here goes. Today, the Verge newsroom got into a heated debate about whether or not vampires can poop. I'm not kidding.
Vampires don't make sense
"Of course not!" one reporter cried. "They don't breathe, therefore they don't have the metabolism to process blood as food." That made sense. "Well, the blood isn't passing through a digestive tract," said an editor. "Blood rejuvenates them by magic, so whatever happens is happening on contact with the vampire's mouth or skin, without any need for excretion." That made sense, too. "Can we just concede," another reporter asked, "that if they don't excrete the blood they ingest as food, they're necessarily breaking the law of conservation of mass?" Then my head exploded.
Chris Ziegler came across the perfect answer we needed. It was on Yahoo! Answers, and it reads as follows:
1. Vampires, defined as a humanoid being that MUST consume blood or energy to survive do not exist. Cut and paste time, as it is too much work to type this out over and over and I "recycle" my own answers instead of retyping them so here goes. A brief discussion of the human digestive system and then the probable vampire population given an exponential growth rate should explain why vampires are not possible.
2. The human body is not designed to process large amounts of blood for nutrition. There is not enough protein, carbohydrates, and fats present in blood to maintain a complex creature such as Homo Sapiens or any theorized offshoot mutations. When a human ingests food it is first broken up into a bolus by chewing, then churned up in the stomach with digestive juices to form a mass called chyme. It then passes through the pylorus into the duodenum, part of the small intestine where it mixes with bile salts and secretions from the pancreas and liver which continue breaking it down on a molecular basis, mostly affecting fats at this point. The broken down nutrients pass through the wall of the intestines and into the bloodstream where they are carried to each cell or stored for later use. Indigestible bulk continues through the intestines, turning a dark brown from the bile. Water is absorbed from this mass in the large intestine depending on the needs of the body - a well-hydrated person will usually have a softer stool than a dehydrated person will. Water also enters the bloodstream, and this is what helps to maintain blood pressure. The pressure tends to balance itself in a healthy person because the bloodstream goes through a formation in the kidney called the Loop of Henle, where the narrowing blood vessel forces excess water and cellular waste such as urea out through the cellular wall into the kidneys, where it is excreted through the ureters into the bladder, and then out of the body via the urethral passageway.
3. IMPORTANT - A person physically unable to process his own food for nutrition therefore also could not process blood - it's the same process. Ingested blood does not transmit directly to the veins anyway - it would be chemically broken down by the digestive system.
4. Theoretical ingestion of blood to supply these nutrients would therefore have to occur at least once a day, and would require the ingestion of the entire blood supply which could not happen as the stomach is far too small to hold that much liquid volume. Hold up your clenched fist - under normal conditions your stomach is about that size. Furthermore, such a mass would be difficult to pass thru the intestines as it has no fibrous bulk, would create an intestinal impaction, causing massive vomiting from the large concentration of iron present, and any "real" vampire would have to eventually expel the waste, which would come out as a black, tarry, smelly goo, just as stool does when blood is present from a upper GI bleed.
ANYONE who tells you such things are "real" is either living in a fantasy, lying through their teeth, has mistaken autonomic biofeedback adrenaline/endorphin release for "draining", or are caught up in a delusion bordering on mental illness.
Drinking blood is a behavior of choice, not one of physiological necessity.
I'm a Nurse, real education, real experience.
Lord Bearclaw of Gryphon Woods