Water (AQA GCSE Food Preparation & Nutrition)

Water

• Water is not technically classified as a nutrient because it does not provide any nutrition to the body, however, it does play many essential roles in the human body

• Water enters the body through the consumption of fluids and in many types of foods

  • consuming water increases the hydration of the body

  • this must be carefully regulated to stay healthy

• It leaves the body via sweat, exhaled in breath, and in urine produced by the kidneys

  • the kidneys play an important role in regulating the quantity of water in the blood by producing more urine if there is too much water, and less urine if there is not enough

Functions of water

• When urine is produced in the kidneys, waste water is eliminated from the blood

  • in addition to this, there are several other waste products that are filtered out of the blood to be expelled from the body in the urine, such as urea - a toxic chemical from the breakdown of excess proteins

  • it also helps to prevent constipation

• Water is able to absorb a lot of energy when it converts from a liquid to a gas

  • when the body temperature raises too high it triggers sweat glands to release sweat

  • when liquid sweat is released onto the surface of the skin it absorbs heat energy from the blood vessels that sit under the surface of the skin

  • it absorbs a lot of energy and uses it to convert from a liquid into a gas

  • the removal of heat energy helps to cool down the blood and reduce body temperature

• Water passes through the digestive system after it is consumed

  • water in saliva helps to turn solid food into a paste that can be pushed easily through the digestive system

  • stomach acid is diluted in water, which then passes out of the stomach and helps to push the digested food through the small intestine and forms faeces

• Water helps with transport throughout the body as many areas of the body are filled with a fluid that is mostly water. Important substances and waste products are dissolved in the water and diffuse through the body to move to their required destination

  • blood is mostly water

  • tissue fluid around our cells is mostly water

  • the cytoplasm inside cells is mostly water

Sweating during exercise image

Un-perfekt, via Pixabay

Consuming the correct amount of water

• Many factors affect the quantity of water that needs to be consumed daily. These include:

  • age

  • gender

  • diet

  • levels of physical activity

  • climate

• In the UK, the NHS recommends consuming around 1.2-1.8 litres of water per day, equivalent to around 6-8 glasses

• Drinking any kind of fluid increases hydration, however, water is the best drink to achieve the most efficient hydration

  • coffee and alcoholic beverages are not very effective at increasing hydration

• Around 20-30% of daily hydration comes from food and 70-80% from drinks

• Drinking too little water can lead to dehydration. This in turn can cause headaches, lack of energy, and light-headedness

• Drinking too much water can lead to water intoxication

  • this causes cells to swell with water, including cells in the brain and can cause seizures and lasting damage

  • drinking too much water is very rare and mostly occurs when people go out of their way to over-drink, such as in water drinking competitions or when competing in endurance sports or extreme military training

Drinking water in hot climates image

Ksenia Chernaya, via Pexels