The brain is over 90% water and requires approximately 2 litres of water everyday. When I say water, I'm not referring to the water in your tea or coffee or your energy/soft drinks, I mean plain, pure and clean drinking water. Citrus is the only thing you can mix with your water and still allow it to cross the blood barrier of the brain, this process is known as osmotic precipitation.
The brain hydrates differently to the rest of the body. It hydrates directly from the stomach. The rest of the body on the other hand hydrates from the alimentary canal (small intestines) and therefore can hydrated from wet foods and mixed drinks.
So if you do not consume enough pure water with a little citrus everyday, your tiny capillaries in your head will slowly close, forcing the water in your brain to be recycled... And this of course is called a headache!
This is another massive reason why we try to educate others about removing heavy metals from your tap water, to allow your body to receive clean, and pure water without the toxic rubbish that unfortunately accumulates in tap water – and why we stock, what we think to be the most economical and efficient water purifying system.