Water, water everywhere...

To live all we really need to drink is water. We evolved on a planet covered, as Samuel Taylor Coleridge once put it, with ‘water, water, everywhere.’ We cannot though stomach salt water and had, in pre-modern times, to wait for the cycle that brings rain. As Coleridge also writes, there may be water everywhere, ‘nor any drop to drink.’

You may well imagine how it all went. We physiologically require water to hydrate our bodies and, like food, we were always in search of it. We competed with other animals to find reliable sources of water. We lived along rivers and mountain streams. We learnt how to trap and, in time, dam and channel water.

What is water? As you know from experience, water exists principally in three states: gas, liquid and solid. Biochemists long ago determined that it involves a hydrogen (two of those) and oxygen (one of those) molecules. Physicists say that the structure, density and temperature of the H2O molecules determine whether it comes in gas, water or ice.

The structure of water in gaseous and ice state is well understood by biophysicists. This is why: the bonds that hold hydrogen and oxygen together is highly structured and finely ordered, in gaseous state and, though more loosely structured, as ice. Lower the temperature of water to zero degree centigrade and solid ice crystals emerge.

Liquid water is tricky to understand because how do highly ordered and finely structured H2O molecules constantly disintegrate and re-form again and again? How can molecular order break down and rebuild itself instantaneously to become a flowing magnitude of mass that, as a flood, having such enormous power? How does water work?

The next time you water your garden using a hosepipe, and if you bother to observe nature closely enough, you will be witness to a scientific mystery in what is after all an everyday domestic chore. How does liquid water break up as it does at the end of the hosepipe’s jet stream? The science community is still not sure.

Water existed on our planet billions of years before we emerged about 150,000 years ago. By then, we had a refined physiological system, finessed over millennia by our ancestors and their ancestors, that depended on water. What are the physiological functions of water?

From a biological standpoint, the Wikipedia entry for water reads, ‘water has many distinct properties that are critical for the proliferation of life that set it apart from other substances. It carries out this role by allowing organic compounds to react in ways that ultimately allow replication. All known forms of life depend on water.’ (www.wikipedia.com accessed 7 December 2007).

Water is vital both as a solvent and essential to many metabolic processes within the body. It is also central to what in biochemistry is known as acid-base neutrality and enzyme function, in particular the digestion of food. It is a cleansing agent and has antibacterial properties. It is central to photosynthesis and respiration in plants.

As hunters and gatherers for most of time we have been on this planet, sources of drinkable water have directed our migration and settlement. In these journeys we likely learnt to eat fruit as they hung or fell off trees that bore them. Juices of fruit become a great luxury, an elixir, though too much of it can cause digestion and other problems.

In our journey, we stumbled across rotting fruit, and learnt to extract from these alcohol-bearing juices. This happened more likely in tropical and sub-tropical areas where fruit was in abundance. Wine from grapes has a long history that certainly goes back to the Egypt of the Pharaohs, the Greeks and Romans and likely well before that.

We also learnt to extract alcohol from agricultural products like barley (whiskey) and potatoes (vodka). Some of the highest alcohol content is found in spirits made in the areas of the world that were or are still presently very cold. Alcohol generates bodily heat. Rum (molasses) and Tequila (cactus) were developed in hot climates, illustrating its ubiquity.

Unlike water and juice, our bodies do not need alcohol and it is, in fact, a poison. Some of us possess the biological machinery to take the ethanol of the bloodstream, typically those whose ancestors were exposed to alcohol over the millennia. With abuse and as we get older the liver cannot its job as well anymore and the poison gets right into our cells and causes great harm.

All we really need is water.