Eat your water: Hydrating foods to eat this summer (and those to avoid)

We are all well versed as to how eating a nutritious diet, regular exercise, refreshing sleep and keeping stress levels in check are all essential to optimal health and wellness, but how often do we think about our hydration?

Our latest blog looks at the importance of staying well hydrated and what foods, as well as water, can help you do this.

The importance of staying hydrated

Staying well hydrated is one of the best healthy habits you can adopt to support your health, and often the one most easily overlooked. Water is essential for life and involved in virtually every process in the body. From allowing our circulatory system to carry oxygen and nutrients to the cells, to supporting the kidneys to excrete waste products and helping to keep our joints and skin lubricated and functioning optimally – water is undoubtedly a vital nutrient.

The body is constantly losing water through everyday activities such as sweating, bowel movements, urinating, even breathing and if this fluid isn’t replenished, we can become dehydrated. As we enter the British summer and hopefully some warmer weather (fingers crossed) we need to be especially mindful of our liquid intake, to replace the fluid we lose through sweat. Infants and young children, older adults and those who engage in regular exercise are at a higher risk of dehydration, so should pay extra attention to regularly topping up their fluid levels.

Let’s have a closer look at how staying hydrated supports optimal health

Regulates body temperature

The regulation of body temperature is a complex process that involves several mechanisms working together to maintain a stable internal temperature, and proper hydration plays an integral role in this process. For example, water can absorb large amounts of heat, governs the body’s main cooling mechanism of sweating and supports blood volume and circulation, which are both essential for thermoregulation. When the body is dehydrated, it can struggle to dissipate heat effectively, and improving hydration levels can support the body’s natural cooling mechanisms. 

Improves brain function, mood and energy levels 

Water accounts for 75% of brain mass and plays an important role in its function. Dehydration has been shown to negatively affect cognitive performance, such as short-term memory and attention, add to fatigue, reduce alertness, lower self-esteem and affect mood. Conversely, rehydrating with water has demonstrated the ability to alleviate these negative symptomsⁱ.

Someone can be considered dehydrated if they lose as little as 3% of their body weight from water depletion, but as little as 1-2% loss can impair cognitive performance and memory.ⁱⁱ It is consistently reported that even in mild dehydration, mood is influenced, fatigue is greater, and alertness is lower,ⁱⁱⁱ so staying well hydrated is essential for maintaining great energy levels and mentally performing at peak.^iv

Supports digestive function

A low intake of water results in a low water content in the faeces, contributing to functional constipation. Constipation has been shown to alter the microbial balance in the gut, and it is thought that low water intake may lead to direct or indirect changes in the gut microbial community, which can have knock-on effects for overall digestive health.^v

Boosts physical performance

As well as its striking effect on mental performance, maintaining great hydration also supports optimal physical performance. Approximately 76% of our muscle mass is water, and while many of us pay close attention to exercise, diet and supplements to support our muscle health, water is amongst the most important nutrients to help us perform at our physical peak.

Studies have shown that a loss of as little as 1.5% water from the body quickly reduces levels of muscle strength.^vi When we consider that athletes commonly lose 6-10% of their water weight through sweat^vii, it is apparent how important it is to adequately rehydrate when we exercise regularly. 

Proper hydration is also essential for supporting musculoskeletal health in general, to help you to keep flexible and mobile. Water is a key component of the synovial fluid that helps to lubricate and acts as a shock absorber to the joints. Cartilage, the cushioning in your joints, also relies on proper hydration to keep it strong, resilient and to help prevent wear and tear.  

Supports detoxification

The elimination of toxins, or detoxification, allows the body the opportunity to rid itself of waste and potentially harmful compounds. If toxins are left in the body, they can begin to accumulate over time and can disrupt the body’s natural physiological function and lead to disease. A number of different organ systems are involved in detoxification and excretion, including the liver, bowels, bladder, skin and lungs, and adequate water is necessary for all these organs to function:  

• Adequate water intake allows toxins to be taken away from the cells and transported to the kidneys to be excreted, and by diluting these toxins, they can be flushed out more effectively 

• The liver relies on adequate hydration to filter toxins and for overall functioning 

• As we’ve already discussed, dehydration can contribute to constipation. By preventing constipation and promoting regular bowel movements, adequate water ensures that toxins can be effectively excreted via the faeces.   

• Water helps you to regulate body temperature by sweating, which is also a route for eliminating toxins 

• Adequate hydration supports the lymph system, which collects and removes cellular waste and toxins  

Keeps skin healthy

The skin is the body’s largest organ, and like every other organ and system in the body, the skin needs water to function properly. Healthy skin equates to well-hydrated skin. Adequate skin hydration is essential for skin homeostasis, and it also maintains barrier function, adequate tissue elasticity, and helps to keep levels of inflammation in check.^viii

Upping your water intake has been shown to increase the hydration levels in the skin, reduce clinical signs of dryness and roughness and improve skin elasticity in as little as 30 days.^ix

Prevents headaches

Dehydration can lead to the development of headaches and serve as a trigger to migraine in some (as well as impairing concentration and increasing irritability), and in these cases, rehydrating with water can alleviate the headache in as little as 30 minutes.^x

A number of other health conditions can be linked, at least in part, to dehydration. These include (but by no means limited to):^xi

• Hypertension 

• Impaired kidney function 

• Dental diseases 

• Gallstones 

• Urinary tract infections 

• Kidney stones 

… so, we really begin to see that proper hydration is key to our health and wellbeing and should be given the same attention as our diet, lifestyle and supplements. So now let us look at how we can make sure we are well hydrated.

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Hydration 101: How to hydrate

Drink water! 

Ensuring that you drink plenty of water each day is certainly one of the easy ways to ensure that you maintain good hydration. While there are different opinions about the optimal amount of water to drink each day, and this will vary from person to person, most of us could benefit from upping our intake. The NHS recommends drinking 6-8 glasses of water per day (around 1.2 – 1.5L), which is a great starting point.^xii

People who may need to drink more fluids are those who are pregnant or breastfeeding, ill or recovering from an illness, engaging in regular strenuous exercise, or those in hotter climates.

Hydrating drinks that aren’t water

It isn’t just water that can help to keep us hydrated; caffeine-free herbal teas such as rooibos and peppermint, milk, coconut milk and various fruit and vegetable juices are all great options. Plus, there are wonderfully hydrating drinks high in natural electrolytes (see below!).

Drinks that can dehydrate you

On the other hand, some drinks can contribute to dehydration, so should be enjoyed in moderation: 

• Alcohol is a diuretic, which causes your body to remove fluids from your blood via the renal system so it’s important that you alternate your alcoholic drinks with water to avoid dehydration (known as zebra striping). This can also reduce your risk of the dreaded hangover. 

• Coffee, when taken in moderation can contribute to your water intake, but if you drink large amounts, it can dehydrate you due to its diuretic effects. Why not swap one or two of your coffees for a refreshing herbal tea?  

• Energy drinks often contain large amounts of caffeine, which, as we know, can be dehydrating. They often contain sugar or artificial sweeteners, as well as other chemicals that can negatively affect our health – so you should aways opt for water or one of the natural electrolyte drinks below.  

• • Fizzy drinks that often contain the sugars glucose and fructose have been shown to cause dehydration and renal injury, despite the high water content.^xiii Diet fizzy drinks with artificial sweeteners, such as the commonly used aspartame, which has been classified as a possible carcinogen by the World Health Organisation, should not be considered a healthy alternative. 

Hydration & electrolytes 

Electrolytes are essential minerals in your body that have an electrical charge, such as sodium, calcium, magnesium and potassium. They are vital to many of the key functions in your body, including balancing the amount of water in your body, balancing your body’s pH levels, moving nutrients into and waste out of your cells, transmitting nerve signals, muscle contraction, helping with blood clotting and regulating your blood pressure.

While water is essential for ensuring adequate hydration and helping to maintain electrolyte balance, if you become dehydrated, for example after an illness or intense exercise, it is important to replace both the water and electrolytes that your body has lost.  

Great ways to replenish your electrolytes include: 

• Coconut water – high in potassium, with some sodium and magnesium (just make sure you buy one with no added sugars) 

• Bone broths 

• Pickle juice (sauerkraut anyone?!) 

• Fruit and vegetable juices/smoothies 

• Lemon water with sea salt – adding a pinch of sea salt or Himalayan pink salt and a squeeze of lemon juice to your water makes a great, homemade electrolyte drink 

• Eat a varied diet with plenty of natural electrolyte condition foods such as leafy greens, potatoes (in their skins), avocado, sweet potatoes, bananas, dried fruits, dairy products, beans, lentils, nuts and seeds. 

Eat your water – the foods that help you stay hydrated

It isn’t just what you drink that can help to keep you hydrated this summer – the food you eat provides around 20-30% of your total water intake. By choosing to include the following foods in your daily diet you will be helping to top up your hydration levels as well as supporting optimal wellbeing with great sources of fibre, vitamins, minerals and powerful phytonutrients. 

Food	% Water	Other health benefits
Cucumber	96	Rich in potassium, phosphorus and magnesium as well as vitamin K
Iceberg lettuce	96	Rich in fibre, vitamins A and K, potassium and zinc
Celery	95	Rich in fibre, vitamins A and K, folate and potassium
Tomatoes	95	Rich fibre, vitamins C and K, folate and potassium. Also a great source of protective lycopene
Courgette	93	Rich in fibre, manganese, potassium, magnesium, and vitamins A, C and K.
Watermelon	91	Rich in vitamins C and A, several B vitamins, potassium, zinc, copper, and many other minerals. Also a great source of lycopene
Spinach	91	Rich in magnesium calcium, iron, potassium, vitamins A and K, fibre, and folate
Strawberries	91	Rich in vitamin C, fibre and various antioxidants
Melons	90	Be it cantaloupe or honeydew, melons are also rich in fibre, vitamin C, potassium, folate and magnesium
Broccoli	89	Rich in fibre, iron, potassium, vitamins C and K and a range of antioxidants

Foods that can add to dehydration

On the other hand, there are some foods that can add to dehydration so are best avoided or eating in moderation. These include: 

Too much salt

While sodium is an essential electrolyte, having too much in your diet, through processed foods, processed and smoked meats, ready meals, fried foods and salty snacks (all foods which are over-consumed in the typical western diet) can result in it concentrating in your bloodstream. The body wants to be in equilibrium, so will pull sodium from our cells into the blood to maintain balance, thus causing dehydration in our cells.^xiv

Too much protein

While the benefits of getting adequate protein are unequivocal, very high protein diets can have a dehydrating effect. Protein is broken down into nitrogen in the body, where high levels of water are required to metabolise it. Excess protein can also be taxing on the kidneys, causing it to excrete more fluids (in the way of urine) as it rids the body of the excess nitrogen, producing a diuretic effect.^xv

Too much sugar

Another common feature of the typical western diet, eating high levels of sugar will cause an osmotic effect: a pull of sugar from our cells into the bloodstream, contributing to dehydration. The kidneys then have to work hard to filter the sugar from the blood and excrete it, contributing to its diuretic effect.  

Healthy hydration habits 

Follow these tips to ensure you keep well hydrated over the summer months: 

1. Carry a water bottle

   Not only is it better for the planet but having a reusable water bottle with you throughout the day, and keeping it topped up, will encourage you to sip regularly and keep your hydration levels topped up, rather than waiting until you feel thirsty. And remember to drink more after exercise or in hotter climates.

2. Zhuzh it up

   If the thought of plain water leaves you feeling less than inspired, add in some sliced citrus or a sprig of fresh lime and pour over ice for a refreshing, healthy treat.

3. Supercharge your salads

   Is there anything nicer than a zingy, colourful salad on a warm day? Pile your plate with salad leaves, crunchy cucumber and tangy tomatoes – plus a rainbow of other plants foods for a nutrient-dense, hydrating and delicious meal!

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References

I. Zhang N, Du SM, Zhang JF, Ma GS. Effects of Dehydration and Rehydration on Cognitive Performance and Mood among Male College Students in Cangzhou, China: A Self-Controlled Trial. Int J Environ Res Public Health. 2019 May 29;16(11):1891. doi: 10.3390/ijerph16111891. PMID: 31146326; PMCID: PMC6603652.

II. Shaheen NA, Alqahtani AA, Assiri H, Alkhodair R, Hussein MA. Public knowledge of dehydration and fluid intake practices: variation by participants’ characteristics. BMC Public Health. 2018 Dec 5;18(1):1346. doi: 10.1186/s12889-018-6252-5. PMID: 30518346; PMCID: PMC6282244.

III. Benton D, Young HA. Do small differences in hydration status affect mood and mental performance? Nutr Rev. 2015 Sep;73 Suppl 2:83-96. doi: 10.1093/nutrit/nuv045. PMID: 26290294.

IV. Liska D, Mah E, Brisbois T, Barrios PL, Baker LB, Spriet LL. Narrative Review of Hydration and Selected Health Outcomes in the General Population. Nutrients. 2019 Jan 1;11(1):70. doi: 10.3390/nu11010070. PMID: 30609670; PMCID: PMC6356561.

V. Sato K, Hara-Chikuma M, Yasui M, Inoue J, Kim YG. Sufficient water intake maintains the gut microbiota and immune homeostasis and promotes pathogen elimination. iScience. 2024 May 3;27(6):109903. doi: 10.1016/j.isci.2024.109903. PMID: 38799550; PMCID: PMC11126815.

VI. Barakat, Christopher MS, ATC, CISSN1; Pearson, Jeremy MS1; Escalante, Guillermo DSc, MBA, ATC, CSCS, CISSN2; Campbell, Bill PhD, CSCS, FISSN3; De Souza, Eduardo O. PhD1. Body Recomposition: Can Trained Individuals Build Muscle and Lose Fat at the Same Time?. Strength and Conditioning Journal 42(5):p 7-21, October 2020. | DOI: 10.1519/SSC.0000000000000584

VII. Ayotte D Jr, Corcoran MP. Individualized hydration plans improve performance outcomes for collegiate athletes engaging in in-season training. J Int Soc Sports Nutr. 2018 Jun 4;15(1):27. doi: 10.1186/s12970-018-0230-2. PMID: 29866199; PMCID: PMC5987390.

VIII. Załęcki, P., Rogowska, K., Wąs, P., Łuczak, K., Wysocka, M., & Nowicka, D. (2024). Impact of Lifestyle on Differences in Skin Hydration of Selected Body Areas in Young Women. Cosmetics, 11(1), 13. https://doi.org/10.3390/cosmetics11010013

IX. Akdeniz M, Tomova-Simitchieva T, Dobos G, Blume-Peytavi U, Kottner J. Does dietary fluid intake affect skin hydration in healthy humans? A systematic literature review. Skin Res Technol. 2018 Aug;24(3):459-465. doi: 10.1111/srt.12454. Epub 2018 Feb 2. PMID: 29392767.

X. Popkin BM, D’Anci KE, Rosenberg IH. Water, hydration, and health. Nutr Rev. 2010 Aug;68(8):439-58. doi: 10.1111/j.1753-4887.2010.00304.x. PMID: 20646222; PMCID: PMC2908954.

XI. Popkin BM, D’Anci KE, Rosenberg IH. Water, hydration, and health. Nutr Rev. 2010 Aug;68(8):439-58. doi: 10.1111/j.1753-4887.2010.00304.x. PMID: 20646222; PMCID: PMC2908954.

XII. https://www.nhs.uk/live-well/eat-well/food-guidelines-and-food-labels/water-drinks-nutrition/

XIII. García-Arroyo FE, Cristóbal M, Arellano-Buendía AS, Osorio H, Tapia E, Soto V, Madero M, Lanaspa MA, Roncal-Jiménez C, Bankir L, Johnson RJ, Sánchez-Lozada LG. Rehydration with soft drink-like beverages exacerbates dehydration and worsens dehydration-associated renal injury. Am J Physiol Regul Integr Comp Physiol. 2016 Jul 1;311(1):R57-65. doi: 10.1152/ajpregu.00354.2015. Epub 2016 Apr 6. PMID: 27053647; PMCID: PMC6195650.

XIV. Zhang J, Zhang N, Liu S, Du S, Ma G. Young Adults with Higher Salt Intake Have Inferior Hydration Status: A Cross-Sectional Study. Nutrients. 2022 Jan 11;14(2):287. doi: 10.3390/nu14020287. PMID: 35057468; PMCID: PMC8778661.

XV. Cuenca-Sánchez M, Navas-Carrillo D, Orenes-Piñero E. Controversies surrounding high-protein diet intake: satiating effect and kidney and bone health. Adv Nutr. 2015 May 15;6(3):260-6. doi: 10.3945/an.114.007716. PMID: 25979491; PMCID: PMC4424780.

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nutrition@cytoplan.co.uk
01684 310099

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Last updated on 26th June 2025 by cytoffice