We tend to imagine that purity is the ultimate indicator of the quality of water. So why is 100%, ultra-pure water not good for us?
Well the simple answer is that water (H20) purely comprised of hydrogen and oxygen doesn’t provide our body with the natural electrolytes and salts we need to survive.
There is no such thing as truly pure water in the natural world. Even water in the purest springs and lakes contains small amounts of dissolved minerals such as sodium, chloride, potassium, calcium and magnesium.
When these minerals dissolve in water, they form the ions which we commonly refer to as electrolytes.
According to eatbalanced.com,
“Maintaining the correct concentrations of these ions in and outside cells in the body is essential for transmitting electrical impulses along nerves and for muscle contraction. They allow us to perform all the “bioelectrical” functions such as moving, heart-beating, thinking, and seeing.”
But not only does pure water fail to provide these essential electrolytes, it tries to rob your body of them when you drink it, potentially creating a fatal imbalance (if you drink enough of it).
This is a result of a process of diffusion, in which dissolved material tends to move from more concentrated solutions to less concentrated ones.
You can think of it this way: imagine a room with no gravity, split in half down the middle. You throw a couple hundred bouncy balls into the left side of the room. Since there’s no gravity, they bounce around everywhere.
But if you cut a bunch of holes in the barrier, they will slowly start to spread over to the right side. Some may cross back over to the left, but eventually, they will be evenly distributed across the entire room.
That’s how diffusion works inside you as well.
One of the reasons water is the main component of your body, from you lungs and skin to your blood and organs, is because it’s a universal solvent (ie. it can dissolve anything soluble and is neutral).
The water in your organs (the left side of the space room) maintains very specific levels of minerals (the bouncy balls).
When you drink ultra-purified water, it pulls the minerals out of your blood just like the right side of the space room pulled some of the bouncy balls over from the left. Ultra-pure water will even strip the copper off the inside of a pipe!
If you drank enough of it, the lack of minerals would eventually kill you.
These dissolved minerals, often referred to as “impurities”, are also what gives us the different flavors we taste when we consume different tap waters or brands of bottled water.
David Rees of National Geographic examined “Ultra-Pure” water. Check out the video below to see what he found.