Water
• Inorganic
• Not energy-yielding
• Essential
Objectives
• After reading Chapter 7 and class
discussion, you will be able to:
–Define terms associated with
water and body fluids
–Describe the fluid composition of
the body
–Describe water balance
Objectives
• Identify sources of water and % of
water in selected foods
• Discuss symptoms of dehydration
• Apply oral rehydration therapy
(ORT)
• Describe functions of water
Functions of Water
• Transport
• Solvent
• Lubricant
• Maintain blood volume
• Body temperature regulation
• Structural support for molecules
• Participate in metabolic reactions
Functions of Water
• Transport
–Carries nutrients to
the cells and carries
away waste materials
to the kidneys and out
of the body in urine
Functions of Water
• Solvent
–Keeps the following in
solution so they can
participate in metabolic
activities:
•Minerals
•Vitamins
•Glucose
•Many other small
molecules in the body
Functions of Water
• Lubricant
–Acts as a lubricant or
cushion around joints;
in the eye, the spinal
cord
–In pregnancy cushions
the amniotic sac
surrounding the fetus
Functions of Water
• Maintains blood volume
• Body temperature
regulation
–evaporation of sweat
from the skim removes
excess heat from the
body
Functions of Water
• Structural support
–Maintains the structure
of large molecules such
as protein and glycogen
• Metabolic reactions
–Water participates in
every step of the process
of converting food to
energy and tissue
Body Composition
60%
Water in the Body
• Nutrient composition of the body
–Water = 60%
–Fat = 13-31%
•Male = 13 -21%
•Female = 23 -31%
–Carbohydrate, Protein, Vitamins,
Minerals, Other = 9 – 27%
Water in the Body
• Example: 150# body
–Water = 90#
–Fat = 20 -45#
–Carbohydrate, Protein, Major
Minerals = 15 -40#
–Vitamin, Minor Minerals = < 1#
Water In The Body
• Adult body composition is 60%
water; higher in children
• Water is ¾ of weight of lean tissue
• Water is ¼ of weight of fat tissue
• Proportion of water smaller in
women, obese, and elderly
Body Fluids
• Intracellular
• Extracellular
– Interstitial
– Intravascular
Water In = Water Out
Water Balance
• Water losses
– Obligatory losses=500cc/day (2 c.)
• Needed to dispose of body wastes
– Insensible losses – lungs, skin
• Water sources
•Food sources (700-1000 cc)
•Liquid sources
– Water vs. Liquids
Fluid:Nutrient Comparison
Fluid
Free Water (cc)
Calories/Protein
Water
240 cc (100%)
0/0
Juice (Apple)
210 cc (88%)
111/0
Whole Milk
214 cc (89%)
150/8
Instant
Breakfast
217 cc (80%)
250/13
Fruit Beverage
Supplement
191 cc (79%)
300/10
How Much Water is Enough?
Recommended Water Intake
• 1 cc/kcal (30-35 cc/kg)
• 6-10 cups per day
• Adequate Intake (AI):
• Men=3.7 L/day (about 14 c/day)
• Women=2.7 L/day (about 10 c/day)
Water Balance
• Dehydration
– See Signs of Dehydration
– Treat with Oral Rehydration Therapy
• Water Intoxication
– Hyponatremia
– Athletes
– Elderly
Fluid And
Electrolyte Imbalance
• Replacing lost
fluids/electrolytes
– Oral rehydration
therapy (ORT)
• ½ L. boiling water
• 4 t. sugar
• ½ t. salt
Coffee vs. Water
• What about coffee/caffeine?
• No significant difference in
hydration
• Caffeine naivety
Journal of American College of Nutrition
2000, 2003
For Caffeine Users
Objectives
• After reading Chapter 7 and class
discussion, you will be able to:
– Define terms associated with water
and body fluids
– Describe the fluid composition of the
body
– Describe water balance
– Identify sources of water and % of
water in selected foods
Objectives
• Discuss symptoms of dehydration
• Apply oral rehydration therapy
(ORT)
• Describe functions of water