Why Drinking Human Blood is Dehydrating
While blood plasma is over 90% water, it also contains a high concentration of sodium chloride, or salt. This creates a high osmolality, meaning the salt concentration is much higher than that of normal body fluids. When you ingest a high-salt solution, your body has to use its existing water reserves to flush out the excess sodium through urination.
This process, known as osmosis, pulls water from your cells and tissues into the digestive system and ultimately to your kidneys. The result is a net loss of water, exacerbating dehydration rather than alleviating it. This is the same principle that makes drinking seawater so dangerous; the high salt content forces your body to expend more water to excrete the salt than it took in from the fluid itself. In a survival situation, this can speed up the process of organ failure and death.
The Deadly Side Effects of Ingesting Blood
Beyond dehydration, consuming blood carries several severe health risks. The potential for contracting bloodborne pathogens is a major concern, as raw blood has not been treated to kill viruses or bacteria.
- Iron Overload (Hemochromatosis): Blood is exceptionally rich in iron. While essential in small amounts, humans have no natural way to excrete large quantities of excess iron. Consuming significant volumes of blood can cause iron to build up to toxic levels, damaging vital organs like the liver, heart, and pancreas. Symptoms of iron poisoning can include abdominal pain, irregular heartbeat, and weakness.
- Bloodborne Diseases: Raw, untested blood can carry a host of infectious agents. Diseases like HIV, hepatitis B, and hepatitis C can be transmitted through ingesting infected blood, especially if the recipient has any cuts, ulcers, or open sores in their mouth or digestive tract.
- Digestive Distress: The high protein and iron content in blood can cause severe stomach irritation. The body often reacts to this foreign substance with nausea and vomiting, which further contributes to fluid loss and dehydration.
Comparison: Hydration from Water vs. Blood
To illustrate the stark difference in hydrating potential and safety, consider the following comparison.
| Feature | Plain Water | Human Blood |
|---|---|---|
| Primary Function | Hydration, cellular function | Nutrient/oxygen transport, immune response |
| Hydrating Effect | Purely hydrating; adds fluid | Dehydrating; causes net fluid loss |
| Osmolality | Low; balances body fluids | High; pulls water from tissues |
| Salt Content | Typically minimal or none | High concentration (~9g per liter) |
| Iron Content | Minimal or none | High; risk of toxic overload |
| Disease Risk | Low (if potable) | High; risk of bloodborne pathogens |
| Nutritional Value | None, essential for life | High protein, iron (but poorly absorbed) |
| Kidney Strain | None | High; must process excess salt and iron |
As the table demonstrates, plain water is the only safe and effective way to hydrate the body. The complex and toxic nature of blood makes it entirely unsuitable for consumption, even in extreme survival scenarios.
The Survival Myth: A Desperate and Dangerous Choice
In some survival narratives, drinking blood might be portrayed as a last-ditch effort to survive. However, this is a dangerous misconception. While consuming animal blood in very small, measured amounts has been documented in some traditional societies with careful knowledge of the source, attempting this as a survival tactic is extremely risky. The potential for ingesting bloodborne diseases from an unknown animal, combined with the certainty of exacerbating dehydration, makes it a poor choice. A more viable strategy in a desperate situation would be to seek any other form of fluid, such as rainwater or purified water.
Conclusion
Despite its high water content, human blood is not hydrating and is actively dehydrating when ingested due to its high salt concentration. Combined with the severe risks of iron poisoning and contracting infectious diseases, the practice of drinking blood is medically unsound and extremely dangerous. Trusting fiction or survival myths could lead to fatal consequences. For hydration, the only safe and proven solution is clean, potable water. Always prioritize safe fluid sources and never resort to consuming blood under any circumstances. You can find comprehensive health information from authoritative sources like the National Institutes of Health (NIH).
