In the first days of the New Year, body and mind give us a wake-up call for clarity and renewal.

There are many detox regimes to choose from but, in truth, the guiding principle behind all of them is rehydration.

It's easy to forget we are two-thirds water and that it's our most precious resource- each cell in our body depends on it.

Water carries nutrients and oxygen around the body, aiding in the digestion and absorption of food, the elimination of toxins and other wastes, regulating body temperature and blood circulation.

It also cushions joints and protects tissues and organs from damage.

Even though water is "on tap" in the developed world, most of us are mildly dehydrated. Common symptoms are loss of concentration and fatigue.

The human brain is 95 per cent water, so a mere two per cent drop in our internal water supply can lead to problems with short-term memory, focus and basic maths.

More serious is chronic dehydration, contributing to high blood pressure, headaches, poor immunity and digestive problems.

As the body cannot maintain itself without water, a scarcity could cause any number of diseases.

However, our thirst mechanism is often mistaken for hunger and more often than not, we are dehydrated rather than hungry.

In this country, water is so readily available, it's almost taken for granted.

Even though it covers three-fourths of the Earth's surface and is continuously regenerated through evaporation, 97 per cent is salty sea water and two per cent is frozen in polar ice caps and glaciers.

Only one per cent of the world's water is usable and some is already contaminated by heavy metals, chemicals and bacteria.

As our groundwater reserves become more and more depleted, we need to consider that clean, fresh water is a finite source.

The UN predicts billions of people will face severe shortages of fresh water by 2025 if we keep consuming and polluting our water at current rates.

What can individuals do to conserve water supplies?

We are less likely to waste it, if we learn to appreciate its importance.

Many primary schools now provide water to children and promote its benefits.

Drinking six to eight glasses of water between meals is thought to be sufficient under normal conditions. But the body's requirements for water are increased by heavy exercise, high temperatures or dehydrated, processed foods high in salt and sugar.

So, apart from drinking water, we need to eat a healthy diet to remain hydrated: Fruit and vegetables contain plenty of water and the essential fatty acids in oily fish, nuts and seeds help our bodies hang on to and make use of the water that we do consume.

Conserve water by using only what you really need for brushing your teeth, washing, cooking and cleaning.

Use biodegradable soaps and detergents and avoid water fresheners in toilet bowls.

Don't pour paints, solvents and petroleum-based oils into drains and use natural fertilisers in your garden.

These are worthy New Year's resolutions that will benefit your own health and, if we all participate, will make a difference.

Martina Watts is a qualified Nutritional Therapist at the Crescent Clinic of Complementary Medicine, Brighton (call 01273 202221), and the Dolphin House Clinic, Brighton. Call 01273 324790), or visit www.thehealthbank.co.uk