Water, hydration and health - are we drinking plastic?

When it comes to hydration the evidence is pretty clear - water is essential to life, good health and optimal daily functioning. For World Water Day 2019, osteopath and nutritionist Jared Cox reminds us why we must drink enough water, what enough water looks like, and how to keep a clear conscience whist improving the quality of water we drink.

Why drink water?

Hydration is key to maintaining healthy bodily functions and a good level of physical performance. A 2010 study looking at water’s effect on hydration and health showed that sub-optimal hydration levels negatively impact several key bodily functions, including:

  1. Physical performance

  2. Cognitive performance

  3. Gastrointestinal function

  4. Kidney function

  5. Cardiovascular function

  6. Headaches

  7. Skin health

  8. Chronic disease

How much should we be drinking?

Water needs can vary from person to person and depends on many factors such as metabolism, physical activity, environmental conditions, age, body size and gender. Thus, developing a recommended dietary allowance (RDA) for water is challenging.

And there is conflicting evidence about whether thirst is reliable measure of dehydration.

In his book, 'Your Body’s Many Cries For Water', Dr. Batmanghelidj suggests that drinking according to thirst is not adequate to prevent dehydration. To maintain optimal hydration you should determine your body weight in Kilograms (kgs) and multiply it by 0.033 to determine how many litres you should consume on a daily basis.

Yet in a study in the British Journal of Sports Science, looking at time-trial performance in cyclists, showed that using thirst as a guide resulted in an increase in performance compared with a rate of drinking below or above thirst.

Using the colour of your urine to predict hydration levels is also based on questionable science, according to a ground-breaking investigative article in the BMJ titled 'The truth about sports drinks'. Citing evidence from Oxford University’s Centre of Evidence Based Medicine they suggest that urine colour is unlikely to tell you anything other than how much water is in your bladder - there is little evidence that it reflects the state of hydration of your tissues.

Where should we source our water?

Unfortunately, we live in a very polluted and contaminated world - we have polluted almost every water supply on the planet. Our cities and municipalities must treat our water with chlorine to remove bacteria and other contaminants. Companies like Coca Cola, Pepsi and others have capitalised on this fact and have mass marketed bottled as the best way to access clean fresh water.

But is that true?

Here are 10 reasons to rethink bottled water:

1. Researchers found bottled water is subject to far less stringent safety tests than tap water and is much more likely to be contaminated or become a source of infection.

2. Scientists have found that 90% of the world’s most popular bottled water brands contained an average of 325 tiny plastic particles for every litre of water - double the amount contained in tap water.

3. Plastic water bottles disrupt our endocrine system. A study done in 2011 compared glass bottled water to plastic and found oestrogenic activity is three times higher in water from plastic bottles.

4. Bottled water is wasteful. It takes at least twice as much water to produce a plastic water bottle as the amount of water contained in the bottle.

5. Imported water brands have 300 times more CO2 emissions per litre compared to a litre of tap water.

6. 30% of bottled water sold in the UK supermarkets is simply processed tap water.

7. Plastic water bottles are one of the most common forms of litter in the 8 million tons of plastic that enter our ocean every year.

8. Plastic in all its forms is killing marine creatures, which can get entangled, or mistake plastic for food, causing internal blockages or suffocation.

9. Tap water is much cheaper. A £1.00 1 litre bottle of water will buy you 1000 litre of tap water.

10. By no means is tap water perfect but it is far cheaper, under greater regulations and bio-surveillance, and has far less environmental impact than bottled-water.

Want to make your tap water even better?

There are several methods and devices that can remove impurities, replace minerals and improve the taste and smell of tap water. These include:

- Boiling water

- Activated charcoal filters

- Charcoal stick filters

- Block carbon filters

- Water Ionizers

- Multi-stage under counter filters

- Reverse osmosis

- Distilled water

Some of these methods can be very costly so its best to do your research before making a decision to determine which type of filtration would best suit your needs.

Jared practises as an osteopath at Core Clapton on Wednesdays and Fridays. He is also a qualified nutritionist, something that informs his osteopathic treatment.


Bensadoun, Y., Can I drink tap water in London (and other parts of the UK)? - TAPP Water. 2018. Available at: https://tappwater.co/us/can-i-drink-tap-water-in-london-and-other-parts-of-the-uk/ [Accessed March 20, 2019].

Burley, H., 2015. The land and water footprints of everyday products, Available at: https://friendsoftheearth.uk/sites/default/files/downloads/mind-your-step-report-76803.pdf [Accessed March 20, 2019].

Cohen, 2012. The truth about sports drinks. BMJ;345:e4737.

Goulet, 2011. ffect of exercise-induced dehydration on time-trial exercise performance: a meta-analysis. Br J Sports Med;45(14):1149-56.

Independant, £1 buys 1000 litres of tap water. Or one bottle of the ionised variety | The Independent. 2010. Available at: https://www.independent.co.uk/life-style/food-and-drink/news/1631-buys-1000-litres-of-tap-water-or-one-bottle-of-the-ionised-variety-2002650.html [Accessed March 20, 2019].

Oneless, EXPLORE THE FACTS - OneLessBottle. 2017. Available at: https://www.onelessbottle.org/explore-the-facts/ [Accessed March 20, 2019].

Popkin, B.M., D’Anci, K.E. & Rosenberg, I.H., 2010. Water, hydration, and health. Nutrition Reviews.

Sawka, M.N. et al., 2005. Human water needs. In Nutrition Reviews.

Wagner, M. & Oehlmann, J., 2011. Endocrine disruptors in bottled mineral water: Estrogenic activity in the E-Screen. Journal of Steroid Biochemistry and Molecular Biology.


Core Clapton

Registered Charity: No. 1166246

Registered Address:

161 Northwold Road, Upper Clapton

London, E5 8RL

Telephone: 0300 561 0161

Email: info@coreclapton.org

Clinic Opening Hours

Monday, Wednesday and Friday:

10am - 4pm

Tuesday &  Thursday: Closed

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