Why drinking lots of water is not the best way to stay hydrated

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Being well hydrated matters to our health, but a combination of factors — including a diet of processed food, advancing age, the pills we take and simply not moving enough — can leave us in a state of mild dehydration, according to a new book. 

But as the two authors (a doctor and an anthropologist who has studied indigenous tribes from desert regions) explain here, the solution isn’t simply just to drink gallons of water… 

Most of us live in a constant state of mild dehydration. You might spot the clues in the form of afternoon fatigue, a foggy head, chapped lips, dry eyes, bad breath, headaches, urinary tract infections or constipation.

But dehydration can have more far-reaching effects, including reduced immunity and joint pain. 

Research has also linked it to acid reflux, heart disease, type 2 diabetes and Alzheimer’s disease.

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Dehydration can have more far-reaching effects, including reduced immunity and joint pain

Water is essential for our bodies. We need it to take valuable chemicals, minerals, nutrients and oxygen into our cells.

It also helps maintain our body temperature (through sweat) and helps get rid of waste products. It acts as a shock absorber and lubricant for our joints and tissues, eyes, nose and mouth, helping to protect our organs.

Not only do we need water for these vital functions, we are ourselves largely made up of water. Even by the most modest traditional estimates, about 65 per cent of you is water.

As we get older, this changes — so while babies might be 75 per cent water, in older people this could be as low as 55 per cent. One reason is the age-related decline in muscle mass (muscles are about 75 per cent water).

So yes, being hydrated really does matter. And it is clear from research that even the smallest amount of dehydration can have a big impact on the body and the brain.

We tend to lose two to three litres of water each day through breath, sweat, urine and bowel movements — and if we’re not fully replacing that water loss, that is when we become dehydrated.

At that point, the brain will send out hormone signals to divert water away from non-life-sustaining areas, such as the skin, muscles and joints in order to regulate function of more important organs such as the brain, heart and liver.

That can make tissues and joints stiffer, cause waste by-products such as lactic acid to build up, and contribute to pain-causing inflammation, too.

Recent research (including a study published in 2016 in the journal Psychophysiology and another published in the Journal of Sports Sciences in 2015) shows that even minor dehydration can make both major and minor aches — joint pain, migraines and post-surgical pain — worse.

What’s more, dehydration has been shown to increase brain activity linked to pain, whereas adequate hydration calms it.

For instance, in a study published in 2014 in the journal Anesthesia and Analgesia, brain scans revealed that when participants’ hands were plunged into iced water, there was greater activity in the areas relating to pain when they were dehydrated compared with when they were hydrated.

Other research has found that as little as a 2 per cent reduction in optimum hydration leads to measurable cognitive loss (which returned when the study participants were fully hydrated), affecting performance in tasks that require attention, memory skills, feelings and judgments.

A 2 per cent reduction is about one litre of water. It is frightening to consider that this is enough to blur your concentration.

That same tiny degree of dehydration has been shown to affect blood vessels in a similar way that smoking a cigarette does — even in healthy young men, as a study published in the European Journal of Nutrition in 2017 found.

The researchers, from Harokopio University in Greece, noted that dehydration compromised the ability of the lining of blood vessels to constrict and dilate, which are essential functions for healthy blood flow. If that’s what happens to adults in ideal health, imagine the effects for those of us who are older or who have heart disease risk factors such as type 2 diabetes.

In fact, experts at Harvard University School of Medicine say even low levels of dehydration can increase the risk of a heart attack in people with heart disease.

That’s because when there is less water in your blood, it becomes thicker, so your heart has to work harder to pump blood around the body.

There is also early research suggesting a link between chronic dehydration and the development of Alzheimer’s disease.

Dr Simon Thornton, a professor of neuroscience at the University of Lorraine in France, believes that chronic low-grade dehydration is one of the principal causes behind the development of a number of conditions, including obesity, type 2 diabetes, hypertension and Alzheimer’s. Writing in the journal Frontiers in Aging Neuroscience in 2014, Dr Thornton suggested a possible link between these conditions is brain shrinkage due to dehydration.

This theory of dehydration is supported further by work showing that our total body water decreases with age, as well as with increasing body mass index. And this, in turn, suggests that aged and/or obese and/or diabetic patients could be chronically dehydrated.

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A 2 per cent reduction is about one litre of water. It is frightening to consider that this is enough to blur your concentration

Furthermore, many drugs used to treat cardiovascular disease can block the ability of the cells to effectively hydrate. In other words, these drugs are turning off our bodies’ ability to activate a system that keeps hydration where we need it most.

This is a particular concern for older people, with studies showing that ‘polypharmacy’ — taking more than five different drugs —can seriously increase dehydration among the elderly. (It is estimated that more than half of over-65s in the UK take five or more prescription pills a day.)

In the first study to measure this effect, scientists at Norwich Medical School reported that improving the hydration of patients not only reduced health problems but also led to a calmer ‘and more sociable’ atmosphere — not least, they suggested, because ‘adequate hydration helps ensure good sleep’.

Research shows it is very easy for all of us to fall prey to low-grade dehydration without realising it. One reason is our thirst mechanism diminishes with age, while muscle mass diminishes, too.

Muscle tissue is one of the largest places we bank our water, so our ability to store water declines at around the same time as our body’s signal to drink.

Another surprising source of dehydration is immobility, which slows down water delivery into cells, as well as the outflow of waste particles. All that sitting that most of us do is literally dehydrating us by slowing our body’s flow of water and energy. 

So why not just drink more water? 

Numerous studies show this cascade of consequences can be intercepted by adequate hydration. For children, hydration can mean a better mood and academic results. For those of us prone to headaches, bloating and chronic diseases, it can alleviate symptoms and recharge our lives.

But it may surprise you to learn that evidence increasingly suggests that drinking water by the gallon is not the solution.

For years, we have been told we need to drink eight glasses of water a day. This is based on official recommendations dating back to 1974, but in those guidelines it was expected that 45 per cent of that water would come from food.

Over the years, urban legend has morphed that initially into liquids only and finally to water only.

But when it comes to drinking enough water, quantity is not necessarily quality. Too much water can flush out vital nutrients and minerals from your cells and tissues, harming your health.

The key to good hydration lies in absorption and getting the right kind of water — and studies are beginning to show that consuming the water contained in plants could be more powerfully hydrating than drinking water alone.

This is something borne out by Gina’s work as an anthropologist studying indigenous tribes from desert regions around the world and trying to understand how they survived drought conditions.

When Gina was caring for her elderly mother, who was suffering from chronic dehydration, she decided to copy the practices of the people she was studying by giving her fresh water-containing foods.

For instance, she knew that young men from the Tarahumara tribe in Mexico fuel themselves for their traditional 50-mile marathons by first drinking a type of corn beer with chia seeds. When mixed with liquid, these seeds release a form of ‘gelled’ water that hydrates more effectively over time than liquid alone.

Grinding chia seeds releases more gel by exposing more surface area, so Gina would stir ground seeds into her mother’s orange juice.

Doing that, along with giving her mother two straws in her glass, so doubling her liquid intake per sip, marked the end of her mother’s frequent urinary tract infections.

‘Gelled’ or gel water is found in all living cells, including plants. This water is denser and has more oxygen than liquid, steam or ice, and is better able to transport nutrients throughout the body.

We know this thanks to Dr Gerald Pollack, a bioengineer at Washington University in Seattle, whose studies show that water locked in plants hydrates more efficiently than plain tap water alone.

For instance, having an apple with a bottle of water will hydrate more effectively than drinking two bottles of water because the fibrous material in that apple serves as a sponge to help hold the moisture inside itself longer.

Because these studies are so new, no adequate clinical work yet confirms how well plant water hydrates, but over the past two-and-a-half years, Dana has been working with more than 400 patients on improving their hydration levels, and has seen amazing results that improve their health and quality of life.

Many lose weight, gain energy and vitality and are able to come off their pain medication.

Our hydration ‘prescription’ 

So how can you go about boosting your hydration? A first, vital step is to avoid processed foods, such as pizza, which is not only lacking in moisture but laden with salt, which makes you lose more fluid than you take in.

Similarly, your body needs lots of hydration to process and filter sugar. Alcohol and caffeinated drinks have a similarly dehydrating effect.

Set yourself up for optimal hydration by drinking a large glass of water when you wake up in the morning, ideally with a pinch of sea salt and a squeeze of lemon to aid absorption.

Yes, we did say salt. Unlike table salt, sea salt and rock salt contain more than just sodium — they also contain important minerals such as iodine, iron, calcium and potassium, and some of these help pull hydration into cells. (We add the lemon juice as it contains mineral agents that regulate how water is transferred into cells.)

Also have a glass of water before each meal (this is a great way to spread your hydration evenly throughout the day), filling your plate with high-water-content fruit and veg, and adding in a daily green smoothie made by blending water-filled vegetables and fruit.

To find out more (including hydrating recipes), see our book.

Adapted from Quench, by Dr Dana Cohen and Gina Bria, published by Hachette Go, £14.99. © Dr Dana Cohen and Gina Bria 2021. To order a copy for £13.19, go to mailshop.co.uk/books or call 020 3308 9193. Free UK delivery on orders over £15. Offer valid until Feb 28, 2021.

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