Nutritional Therapy Oxford Dip ION, mBANT
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Drinking Water


Many clients ask: which sort of water is best to drink?

On a hot summer day, it isn’t difficult to remind people that drinking water is important. Even the London Underground is asking people to carry bottles of water!

Hot weather makes us thirstier because our bodies perspire more water to keep our temperature even – and we need to replace that water quickly.

In the UK, we are incredibly fortunate to have high quality tap water that does not carry parasites or disease – unlike the tap water in many other countries. It is also an immense blessing that we don’t have to trudge for hours to collect it. We can, on the whole, simply turn on the mains and drink what comes out.

However, we are also bombarded with choices to make. The shops are filled with bottled water, spring water, mineral water, sparkling or still – and many people use water filters at home. Some people even alkalize their water. Should we pay over and above our existing water rates to achieve better drinking water?

To answer this question, let’s look briefly at water’s properties and why even ‘clean’ and ‘safe’ water in the UK can vary so much in content.

Water properties

Water is what’s called a ‘polar’ molecule: its two hydrogen atoms and single oxygen atom create electrical attractions to particles other than itself. This means it can easily dissolve ionic compounds (such as table salt) and other polar molecules (such as table sugar). In fact, given enough time, water can erode or dissolve almost anything. This is why it is sometimes called ‘the universal solvent’. (Listen here for a fascinating radio podcast on water’s amazing chemical properties!)

Within the human body, water’s ability to dissolve is brilliant for transporting vital vitamins and minerals around the body, and for dissolving and removing toxic substances.

But the story gets much more complicated, when we look at the water we drink.

In addition to dissolving beneficial molecules or ionic compounds, water can also dissolve less desirable particles – such as lead. Famously, lead water piping has caused lead poisoning in humans since Roman times – and today, lead water pipes in old buildings still present problems.

However, the plastic water pipes in modern houses aren’t perfect either: a number of studies have shown they can also leach elements into the water – such as tin, lead and barium – thanks to the ingredients involved in pipe manufacturing processes.

So – should we just drink bottled water instead?

Water bottles

Most bottled water on restaurant tables is glass-bottled, and this will be either ‘spring’ water or ‘mineral’ water. In the UK, ‘mineral water’ must be from a ‘recognised underground source’, have certain amounts of beneficial trace minerals, and can only receive very limited treatments before bottling. Mineral water sources therefore undergo a 2-year testing process before determining their purity. In contrast, ‘spring water’ does not have the 2-year regulatory process and can have treatment to remove pollutants.

In supermarkets and shops, plastic-bottled water is more common. Unlike glass bottles, however, plastic containers can contaminate the water they carry – especially in hot and sunny weather. Leached substances from plastic can disrupt our hormones: a recent study showed that water packed in PET plastic showed a 60-90% higher oestrogenic activity compared to the same kind of water packed in plastic bottles, at levels that can affect human cells. Although plastic contamination may seem a miniscule problem compared to the benefit of disease-free water, it doesn’t take much to disrupt hormones within the body.

Water filters

If we decide to avoid bottles, then, we may consider filtering our tap water. Two popular reasons for filtering are fluoride and chlorine.

Fluoride is pre-added to water supply in many UK areas to benefit dental health. But it is controversial. In 2014 a Lancet article discussed the toxic potential of fluoride, particularly in terms of harming the brain; and it can also interfere with thyroid gland function. The best filtration method for fluoride is ‘reverse osmosis’, which may involve an extra cost if you are on a metered water supply.

Chlorine is used to prevent waterborne pathogens by disinfecting tap water supply. However, it has also received scrutiny for its possible adverse health effects – partly because of the impact of ‘disinfection byproducts’. While the exact risks are controversial – and the official literature notes that chlorine in UK drinking water is well below the WHO maximum safety levels – removing chlorine from drinking water certainly improves taste. Carbon filter products such as ‘binchotan charcoal‘ can both reduce chlorine levels and improve the water’s taste.

Finally – there are now many other water treatment systems, which also claim to ionize and alkalize water. The jury seems to be out on these systems! Certainly, naturally occurring minerals which can make water alkaline – such as calcium or magnesium – are very useful to the body in appropriate amounts. Ionization may create anti-oxidant properties in water, properties which are generally considered a benefit to cell and DNA health. However, when water is alkaline it can also effectively reduce stomach acid. For many people, however, this is absolutely not a benefit, because (paradoxically) acid reflux symptoms often indicate low, not high stomach acid, and can be implicated in number of other health problems.

What to do about drinking water?

Though we can be certain that water is the healthiest way to hydrate, this month’s blog is difficult to conclude simply!

First of all, appreciation for our own easily accessed drinking water might inspire interest in water projects abroad, by charities like Tear Fund or Water Aid.

Secondly, if removing fluorine is your greatest concern, reverse osmosis is likely your best choice – though be aware that it will remove beneficial as well as non-beneficial minerals from the water. If taste and chlorine are your issues, then carbon/charcoal filters should be sufficient. If money is no object and you can recycle easily, glass-bottled mineral water is your best bet.

Finally, perhaps we can amend London Underground’s advice: when you take your water bottle on the train, just make sure it’s not plastic!

Emma Maitland-Carew, Nutritional Therapist in Oxford and Bloxham, Oxfordshire


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Department for Environment, Food & Rural Affairs, 2015. Food standards: labelling, durability and composition. Available at:

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NHS UK, 2015. Fluoride – NHS Choices. Available at:

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Wagner, M. & Oehlmann, J., 2011. Endocrine disruptors in bottled mineral water: Estrogenic activity in the E-Screen. The Journal of Steroid Biochemistry and Molecular Biology, 127(1–2), pp.128–135.





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