UGRC 145: FOOD AND NUTRITION IN EVERYDAY LIFE

Transcription

1 UGRC 145: FOOD AND NUTRITION IN EVERYDAY LIFE Session 4 WATER AS A NUTRIENT Lecturer: PROF. MATILDA STEINER-ASIEDU, SBS, CBAS; University of Ghana, tillysteiner@gmail.com College of Education School of Continuing and Distance Education 2014/ /2017

2 Session Overview Learning Objectives: At the end of this lecture you should be able to: Describe the body s water sources List the routes of water loss Name factors that influence the need for water. Enumerate the consequences of dehydration Explain why water is important Prof M. Steiner-Asiedu Slide 2

3 Session Outline The key topics to be covered in the session are as follows: Topic One: WATER Topic Two: WATER BALANCE Topic Three: Assignment/Discussion For Next Session Prof M. Steiner-Asiedu Slide 3

4 Topic One WATER Prof M. Steiner-Asiedu Slide 4

5 HYDRATION Dehydration: A condition resulting from negative water balance Hyperhydration: A condition resulting from positive water balance Prof M. Steiner-Asiedu Slide 5

6 How Essential is Water? A major component of our body mass. Makes up about percent of a person s weight A person can only survive a few days without water. Without water: Blood pressure rises Heart begins to malfunction Kidneys shut down Prof M. Steiner-Asiedu Slide 6

7 Functions of Water in the Body Transportation: Nutrients Wastes Hormones Enzymes Platelets Blood cells Prof M. Steiner-Asiedu Slide 7

8 Functions of Water in the Body Solvent Universal solvent for all substances in the body Cleansing agent Removal of waste products through urine Prof M. Steiner-Asiedu Slide 8

9 Functions of Water in the Body Lubrication to allow easy movements and flow : Reduce friction at joints Digestive tract saliva make food move easy through the esophagus to the stomach Protects Mucous membranes and keeps them moist Prof M. Steiner-Asiedu Slide 9

10 Functions of Water in the Body Regulation of body temperature Able to absorb and store heat Coolant thus removes heat and cools the body as perspiration and evaporates. Prof M. Steiner-Asiedu Slide 10

11 Functions of Water in the Body As Structural role helps maintain the following : The shape of cells e.g. red blood cells The integrity of cell membranes (coverings) Protects and cushions organs example shock absorber inside eyes, spinal cord Prof M. Steiner-Asiedu Slide 11

12 Topic Two WATER BALANCE Prof M. Steiner-Asiedu Slide 12

13 WATER BALANCE Water Balance : Body s state of hydration Negative Balance: Intake < output Positive Balance : Intake > output Equilibrium : intake = output Prof M. Steiner-Asiedu Slide 13

14 WATER BALANCE : water in The body gains water through the following: Food All fluids (water, beverages) Body's own metabolism Prof M. Steiner-Asiedu Slide 14

15 WATER BALANCE : water out The body loses through body functions: Perspiration Urination Bowel movements (faeces). Note that the amount of water can be more if there is diarrhoa Normal exhalation Vomitting Bleeding Prof M. Steiner-Asiedu Slide 15

16 DAILY WATER LOSS Prof M. Steiner-Asiedu Slide 16

17 WATER BALANCE Prof M. Steiner-Asiedu Slide 17

18 WATER BALANCE Prof M. Steiner-Asiedu Slide 18

19 INDEXES OF HYDRATION STATUS Prof M. Steiner-Asiedu Slide 19

20 Quenching Thirst and Balancing Losses Thirst lags behind a lack of water To ignore thirst is to invite dehydration When a person is thirsty, they may already have lost up to 2 cups of total fluid Water intoxication occurs when too much plain water floods the body s fluids and disturbs their normal composition Can occur if several gallons of water are consumed in a few hours time Can be fatal Prof M. Steiner-Asiedu Slide 20

21 How much does a person need? 8-glasses is the recommendation (4 sachets of water that is about 2000ml) Water needs vary widely among individuals and depend on a number of factors including: Climate Level of physical activity Age Gender Prof M. Steiner-Asiedu Slide 21

22 Importance of water Drink a minimum of 8 glasses to replace what is lost daily. High water intake is associated with a lower risk of kidney stones colon cancer bladder cancer. Less fatigue in the day Prof M. Steiner-Asiedu Slide 22

23 Sources of water intake It is important to note Healthy individuals can stay hydrated by consuming in addition to water juices milk coffee tea soft drink Prof M. Steiner-Asiedu Slide 23

24 Why other beverages are not the best? Many beverages people consume provide additional calories (all sugar drinks and beers) sodium (all drinks with added salt) Fat (drinks with milk or chocolate) NOTE!!! diet soft drinks and teas aren t perfect: chemical sweeteners may actually stimulate a person s appetite! Prof M. Steiner-Asiedu Slide 24

25 Effects of Mild Dehydration, Severe Dehydration, and Chronic Lack of Fluid Prof M. Steiner-Asiedu Slide 25

26 Factors that increase fluid intake Prof M. Steiner-Asiedu Slide 26

27 Water in Foods and Beverages Prof M. Steiner-Asiedu Slide 27

28 Topic Three ASSIGNMENT/DISCUSSION FOR NEXT SESSION Prof M. Steiner-Asiedu Slide 28

29 Take home What is water balance What factors affect needs Prof M. Steiner-Asiedu Slide 29

30 Next week We shall discuss Food Resources Please read handout 4A before class to make you follow the lectures. Prof M. Steiner-Asiedu Slide 30