food –a fact of life eseminar healthy hydration€¦ · · 2017-09-271 ©2010 the british...

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© 2010 The British Nutrition Foundation

Food – a fact of life eSeminar

Healthy Hydration

Laura Wyness and Bridget Benelam,

Senior Nutrition Scientists

British Nutrition Foundation

© 2010 The British Nutrition Foundationwww.nutrition.org.uk/nutritioninthenews/hydration/

www.blackwellpublishing.com/nbu

Benelam B and Wyness L (2010)

“Hydration and health: a review”

Nutrition Bulletin 35 (1):3-25.

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Healthy Hydration

Approximately how much of our body is made up of water?

40%

60%

80%


The body contains a large amount of water

Poor fluid intake can lead to dehydration.

All drinks count to fluid intake except stronger alcoholic drinks such as spirits and wine.

Water is also provided from food (about 20%).

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EXCRETION –

get rid of waste

products via

kidneys and

urine production

REACTIONS –

provides a

medium for all

chemical

reactions in the

body

SWEATING –

for body

temperature

regulation

TEARS –

forms tears to

lubricate our

eyes

CEREBROSPIN

AL FLUID – as a

cushion for the

nervous system

JOINTS –

forms

synovial fluid

to keep our

joints mobile

SALIVA – water

is a key

component in

saliva, helping

us to swallow

Functions of

Water

Why do we need water?


Water Balance

• Our bodies have special mechanisms to ensure we stay hydrated, feeling thirsty is our body’s way of making us drink more

• The kidneys are very important and help our bodies maintain water balance by limiting excretion

• Water is lost by sweating, urinating and breathing

• Water is gained by eating and drinking and we produce a very small amount by metabolism

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Dehydration• Body water volume is tightly controlled and usually

fluctuates by less than 1% per day

• When we are dehydrated we may struggle to focus, feel tired and get headaches

• If it is hot, you are exercising or you have a high temperature you may also need to drink more

• Urine should be a pale straw colour. If it is a dark yellow colour during the day, you might not be getting enough water

• Due to these mechanisms, serious dehydration is very rare


Can we have too much water?

• Yes

• No

• Don’t know

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Over - Hydration

• Drinking too much water is not helpful and in extreme cases may be dangerous

• Our kidneys usually excrete excess water, but if there is extreme over-hydration they may not be able to do so

• This can result in low sodium levels in the blood, which can be very dangerous

• Severe over-hydration is very rare

• If you are frequently urinating and it is very pale, you may be drinking too much


Are you getting enough?

How much should we drink each day?

A) 6-8 glasses of water

B) 6-8 glasses of fluid per day

C) None – we get water fluid from our food

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6 – 8 glasses of fluid per day

The amount of fluid we need changes from day to day, it is affected by many things, including:

• The weather

• Age

• Exercise

But, as a rough guide, try to drink around 6-8 glasses, or 1.2litres per day

This is on top of the water provided by food.


How much are we drinking?

• Data on current water consumption in the British

population are not available.

• National Dietary and Nutrition Survey (2000/01)

estimated average fluid intake from drinks:

British men: 1988ml/day

British women: 1585ml/day

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Drinks


YES!!!

• ‘Fluid’ does not only include water, but water is a great choice as it delivers fluid without adding calories and damaging teeth.

• This should be considered when choosing drinks, as the energy we drink counts towards our calorie intake the same way food does!

• Sugary and acidic drinks may also cause tooth decay and erosion

Do Other Drinks Count?

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Water

Delivers fluid without adding energy or

potentially damaging teeth.

Does not contribute to energy intake.

Flavoured water may provide energy

depending on sugar content


Even Tea and Coffee?

YES!

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Tea and Coffee

• There is lots of confusion regarding tea and coffee affecting your water intake – with some sources even saying you should drink more water when you have coffee

• Moderate amounts of caffeine does not cause dehydration, so tea and coffee do count towards your fluid intake

• Other hot drinks, e.g. herbal teas and hot chocolate also count.

• If these drinks are sweetened with sugar their calorie intake will be increased and they will be more damaging for teeth

• Pregnant women are advised to consume no more than 200mg caffeine a day.

• This is equivalent to: 2 mugs of instant coffee

or 3 cups of tea.


Provides protein, calcium and B vitamins.

Wholemilk contains saturated fat, it is advisable for adults to

choose lower fat milks: semi-skimmed (2% fat), 1% or

skimmed (less than 0.1% fat).

For children aged 1 - 2 years,

wholemilk is recommended.

From 2+ years,

semi-skimmed milk can be introduced.

1% or skimmed milks are not suitable for children until they

are at least 5 years old.

Milk

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Fruit Juices & Smoothies

• Provide water, vitamins, minerals and natural plant substances

• Fruit juices (150ml) count towards one portion of 5 A DAY.

• Smoothies contain puréed fruit, which adds fibre.

Smoothies (150ml juice and 80g crushed fruit) count as two portions.

• However, they both contain sugar and acid so can potentially harm teeth.


Soft Drinks

• Are a source of water, but if they contain

sugar this will count towards your calorie

intake and potentially harm your teeth

• It’s a good idea to swap these for low

sugar / diet versions!

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What is the most popular drink

in the UK?

Tea ...

Coffee …

Tap water …

Bottle water …

Soft drinks …

Fruit juice …

Alcoholic drinks …


What is the most popular drink

in the UK?

Tea ...

Coffee …

Tap water …

Bottle water …

Soft drinks …

Fruit juice …

Alcoholic drinks …

536 ml/person/day

744 ml/person/day

333 ml/person/day

229 ml/person/day

211 ml ‘regular’ & 240ml low calorie/person/day

106 ml/person/day

425 ml/person/day

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Alcoholic Drinks

• These do contain water, but the alcohol acts as a diuretic,

increasing the amount of water we lose through urine

• Drinks with a high alcohol content, e.g. wines and spirits

cause diuresis, making you more likely to be dehydrated.

• Normal strength beer, lager and cider cause a net water gain

overall as the alcohol is more dilute

• It is still important to keep alcohol consumption within the

recommended limits

Men - no more than 3-4 units per day.

Women - no more than 2-3 units per day.


One unit of alcohol is:

• half a pint of standard strength (3 to 5% ABV)

beer, lager or cider;

• a pub measure of spirit;

• half a glass of wine;

• two thirds of an Alcopop.

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Contribution from food

Water is also provided from food (about 20%)

– 80-90% water in fruit and vegetables

– 75-80% water in yogurts

– 65-80% water in rice and pasta

– 40-50% water in cheese

– 30-45% water in bread

– 1-10% water in savoury snacks and confectionary

Foods, such as soups, stews, yogurts have a high

water content.


When do we need extra

water?

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Some people need to take care to

stay hydrated

• Children

• Pregnant and lactating women

• Older adults


Physical activity

Even slight dehydration has been shown to affect sporting performance, so drink before, during and after you train or play a match.

The fluid needed for activity is more than the daily recommendation of 6 to 8 glasses (1.2 litres) each day.

Being dehydrated may mean that:

•You don’t perform your best•Your concentration is impaired•You feel more fatigued

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Conclusion

• Water is essential for life

• For the body to efficiently function we need to maintain optimum hydration

• Water requirements vary from person to person, so remember your urine should be a pale straw colour

• The body has several mechanisms to control the balance of water and usually total body water remains stable.

• Serious dehydration is unlikely in the UK

• Water comes from food and drink

• Beverages also contain calories


Healthy hydration resources

www.nutrition.org.uk/nutritioninthenews/hydration/

healthy-hydration-guide

Available in –

Education News

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Thanks for listening! For more information visit

www.nutrition.org.uk

www.foodafactoflife.org.uk

Future eSeminars:

• 11.10am - 12.10pm Tuesday 23rd November 2010, Interactions between

physical activity and appetite control: Can we reduce the energy gap?

• 12:30pm - 1:00pm Monday 13th December 2010, Satiety

•1:00pm - 1:30pm Wednesday 19th January 2011, What's your beef? Red

meat in the diet

•12.30pm - 1.00pm Thursday 17th February 2011, Omega 3 Fatty Acids and

Heart Disease - Just another fishy story?

•12:30pm - 1:00pm 16th March 2011, Diet and the immune system

food –a fact of life eseminar healthy hydration€¦ · · 2017-09-271 ©2010 the british...

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