Hydration
Photo by Daria Shevtsova
Hydration is an exceptionally important part of nutrition, and it is vital we drink enough fluids to stay healthy. I’m sure we’ve all heard the advice to drink 8 glasses of water per day. But how much do we really need and what counts towards our fluid intake? So let’s talk about water and hydration.
Why do we need fluids?
Water makes up most of our body - 60% in adults -, and plays an essential role in all of our body processes.
We need fluids for:
Body temperature - we regulate our own body temperature by losing more water through the skin - sweat or perspiration - and respiration, which acts to cool the body down and maintain a stable temperature in hot weather conditions. The more we sweat, the more we will need to drink fluids to replace what was lost.
Waste product elimination - fluids help our kidneys get rid of waste products and toxins we no longer want through urination.
Blood thickness & nutrient transport - the plasma in our blood is around 92% water, therefore it is essential in maintaining blood volume and transporting important nutrients and oxygen in our blood throughout the body to our cells that need them.
Digestive health - fluids help our digestive system function properly and reduce the risk of constipation.
Saliva production - fluids make up our saliva, which is involved in the moistening and breaking down of foods we eat.
Joint & eye lubrication - fluids are necessary for the synovial fluid that lubricates our joints and eyes.
Organ & tissue protection - fluids act as a shock absorber - cushion - for organs such as the brain, spinal cord and eyes.
Skin Health - our skin consists of 64% water, good hydration helps keep our skin healthy and avoid skin dehydration.
So it is vital we drink enough fluids to stay healthy and maintain normal body functions.
How much fluids do we need daily?
The amount of fluid we need varies between people based on:
Body size
Age
Physical activity level
Environment - e.g. heat exposure.
Health status - e.g. medical conditions, medication
Diet & alcohol intake
Pregnancy & breastfeeding
So there is no magic number for how much fluid we all need, however, the European Food Safety Authority has set the adequate fluid intake (from all sources including food) at:
2.0L per day for women (>14 years)
2.5L per day for men (>14 years)
Using a standard 250ml glass or cup, this works out as around 8 to 10 glasses or cups per day.
Most of this fluid should be from plain water, even though there are different types of drinks and foods that contribute to your intake.
What counts towards our daily fluid intake?
Plain water is not the only way to stay hydrated, all fluids will help promote hydration. This includes:
Sparkling water
Milk
Flavoured drinks
Fruit Juices
Soft drinks
Tea
Coffee
On top of this, around 20-30% of the fluids we consume come from foods - e.g. soups, stews, fruits and vegetables. Many fruits and vegetables are over 90% water - e.g. courgette, cucumber, tomatoes, oranges & melon - and make a valuable contribution to our fluid intake.
It is advised to limit our intake of sugary drinks and keep fruit juices to one small glass a day as too much added sugar has been associated with dental problems and an increased risk of developing Type 2 Diabetes.
With caffeinated drinks - tea and coffee - it is important to be aware of their stimulating effect, and mild diuretic effect - produce urine more quickly -, however, they are still hydrating as the fluids they provide outweigh the mild dehydrating effect of caffeine.
How can we tell if we are hydrated?
The quickest and easiest way to check our hydration is to look at the colour of our urine.
Pale yellow urine is a sign we are well hydrated, and anything darker is a sign of dehydration. Clear urine - the same colour as water - is a sign of good hydration as long as it isn’t consistently clear, this may be a sign of over-hydration.
What are the signs of dehydration?
One of the first signs of dehydration is thirst! Thirst isn’t just an indication that we need to drink, by the time we feel thirsty, our body is already dehydrated.
Dehydration also shows itself in many different ways:
Dark yellow urine & urinating less
Dry mouth, eyes & skin
Headaches
Fatigue & low energy
Dizziness
Rapid heartbeat
Muscle cramps
Constipation
Tips and tricks to stay hydrated!
Start the day with a glass of water.
Water bottles - get a reusable water bottle and always have it on hand, this helps track water intake and reminds us we need to drink.
Add flavour - add fruit, veg or herbs - e.g. lemon, pineapple, mint, cucumber, or orange - to naturally enhance the flavour of the water.
Eat your water - choose fruits and veg with a high water content - e.g. oranges, grapes, lettuce, watermelon etc. - and make soups during the winter months.
Check urine - monitor for symptoms of dehydration and replenish as needed.
What’s the take-home?
Consuming enough fluids and staying hydrated is vital for our health.
Different factors impact our needs for fluid intake, however, we should be aiming for around 2.0L per day for women and 2.5L per day for men.
The best way to stay on top of our hydration needs is to keep an eye on the colour of our urine - anything darker than pale yellow indicates a need for fluids.
Check out these other Nutrition & Lifestyle posts…
References
British Dietetic Association (BDA). The importance of hydration. 2019. Retrieved June 3, 2022, from https://www.bda.uk.com/resource/the-importance-of-hydration.html
European Food Information Council (EUFIC). How much water should you drink per day. 2020. Retrieved June 3, 2022, from https://www.eufic.org/en/healthy-living/article/how-much-water-should-you-drink-per-day
European Food Safety Authority (EFSA). Scientific Opinion on Dietary Reference Values for water. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA). EFSA Journal 2010; 8(3):1459. Retrieved June 3, 2022, from https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2010.1459
National Health Service (NHS). Dehydration. Health A to Z. 2019. Retrieved June 3, 2022, from https://www.nhs.uk/conditions/dehydration/
