Transcript Water and Electrolytes

Water and The Electrolytes
By Jennifer Turley and Joan Thompson
© 2016 Cengage
Presentation Overview
•
•
•
•
•
•
•
Water and minerals in the body
Water functions & importance
Fluid compartments
Intake needs & sources
Output & loss
Dehydration & intoxication
The electrolytes: Na, K, & Cl
Minerals in the Body
• Minerals are inorganic elements that are
naturally found in earth.
• Major (>5 gm in reference body) & Trace
• Major minerals = electrolytes (sodium,
potassium, and chloride)
• Major minerals in bone = calcium,
phosphorus, and magnesium
• Major mineral in protein = sulfur
• Trace minerals = iron, copper, iodine,
manganese, fluoride, chromium,
molybdenum, selenium, zinc, & cobalt
Water & Minerals in the Body
• Needed in mg or µg amounts (depending on
the nutrient) & based on age, gender, and
conditions of pregnancy and lactation.
• Inadequate/deficient intake → deficiency
signs/symptoms over time.
• Excess (>UL) intake → toxicity signs/symptoms
over time.
• Some foods or food groups provide a good
source of some minerals and not others.
• In general, eat a wide variety of foods from
each of the food groups & drink fluids to meet
mineral and water needs.
Water: Chemical Form
• Water is an inorganic compound
composed of two hydrogen atoms and
one oxygen atom.
• It is abbreviated chemically as H2O.
Functions of Water in the Body
•
•
•
•
•
A medium for chemical reactions
Participates in energy formation
Regulates nutrients & waste products
Helps regulate body temperature
Lubricants & cushions
– joints, eyes, spinal cord, etc.
• Maintains blood volume
Fluid Compartments
Extracellular
25%
interstitial
8%
blood/plasma
Fluid Balance: Intake Needs
• Adult DRI: ♂ 3.7 liters/day ♀ 2.7 liters/day
There is no UL for water
• Another recommend level is 1 ml/Calorie
♂ : 2900 Calories = 2.9 Liters (12 C)
♀: 2200 Calories = 2.2 Liters (9 C)
These may not be optimal
fluid intake levels.
Strenuous physical activity & heat
stress
greatly increase water needs.
Fluid Turnover
Without Perspiration
4% Adults
15% Infants
Fluid Sources and Losses
(in liters)
Importance of Water
Moments without oxygen
Days without water
Weeks without food
~ 60% of total body weight is
water
Fluid Balance: Input & Output
• Optimal fluid intake and output leads to
normal skin integrity, body weight, urine
volume and urine color.
• Enough fluid should be taken in to
produce a clear urine output every 2
hours while awake.
• With insufficient intake and obligatory
output, dehydration results.
Adverse Effects of Dehydration
% Loss Severity
Symptoms
1-2
Mild
Thirst, fatigue, weakness, loss of
appetite
3-4
Moderate Impaired performance, dry
mouth, urine reduction,
impatience, apathy
5-6
Moderate Headache, irritability, sleepiness,
increased respiration
7-10
Severe
Dizziness, muscle spasm,
imbalance, delirium, collapse
How to Become Dehydrated
•
•
•
•
•
Intake of caffeine
Intake of alcohol
Diuretic medications
Sweating
Heat exposure
Effects of Dehydration on Health
Chronic Mild
Dehydration
is linked to:
• Increased Risk
– Urinary tract infection &
stones, constipation,
hypertension, heart disease,
kidney dysfunction,
hyperglycemia with diabetes,
and possibly colon and
bladder cancer and
bronchopulmonary disorders.
Water Intoxication
• Rare, usually from forced water intake,
• Serious life threatening consequences.
• Associated with low blood levels of
sodium (hyponatremia)
–
–
–
–
CNS edema
lung congestion
muscle weakness
Maximum renal clearance (urinary output) ~700 ml
(24 ounces) -1000 ml per hour.
• With heavy exercise, replace both water
and electrolytes.
Sources of Water for the Body
100%
Water, diet soda
90-99%
Nonfat milk, berries, watermelon, celery, lettuce
80-89%
Fruit juice, yogurt, apples, oranges, grapes, carrots
70-79%
Shrimp, banana, corn, potato, cottage cheese
60-69%
Cooked pasta, legumes, salmon, chicken, ice cream
50-59%
Ground beef, hot dog
<50%
Crackers, cereals, pretzels, nuts, butter, margarine, oils
The Electrolytes
• Electrolytes are salts that dissolve in
water & dissociate into charged particles
called ions.
– Sodium: Na+
– Potassium: K+
– Chloride: Cl-
• Electrolytes function in Fluid/Water
balance & acid-base balance (excessive
vomiting can cause alkalosis).
Water Follows Electrolytes
Fluid and Electrolytes
• Drinking water & eating regular foods
restores fluid & electrolyte balance.
• With excessive sweating, bleeding,
vomiting, or diarrhea special drinks
may be used to restore electrolytes.
Sodium
Deficiency & Toxicity
Food Sources: Salt, sea salt, soy
sauce, processed foods, MSG.
Deficiency
Adequacy
Toxicity
(<66% of DRI)
DRI: 1500 mg/day
(>UL)
Approx. <990 mg/day
DRV: 2400 mg
>2,300 mg/day
Cardio-Vascular: hyponatremia, cardiac
failure
Central Nervous System: mental
apathy, weakness
GI System: loss of appetite
Neuro-Musccular: muscle cramping,
skeletal muscle cell injury
Other: renal failure
Normal ECF balance and
volume, plasma osmolarity
and volume, pH balance, and
the membrane potential of
cells
Cardio-Vascular: increased
blood pressure with increased
risk for heart attack and stroke
Other: fluid retention (edema)
Adult deficient, adequate, toxic values
Food Processing and Sodium
Adult DRI: 1,500 mg/day
Chloride
Deficiency & Toxicity
Food Sources: Salt (~2700 mg/tsp), salt substitute (~2600
mg/tsp), sea salt, soy sauce, processed foods with salt, seaweed,
rye, tomatoes, lettuce, celery, and olives.
Deficiency
Adequacy
Toxicity
(<66% of DRI)
DRI: 2,300 mg/day
(>UL)
Approx. <1520 mg/day
(3,800 mg NaCl)
>3,500 mg/day
RDI: 3,400 mg
(5,800 mg NaCl)
Bone & tooth: growth failure in
children
Central Nervous System: mental
apathy
GI System: loss of appetite
Neuro-Musccular: muscle
cramps
Normal ECF balance and
volume and plasma
osmolarity and volume.
Hydrochloric acid
production
Cardio-Vascular: in
combination with sodium,
increased blood pressure
with increased risk for heart
attack and stroke
Quantitative data unavailable for graphical analysis
Potassium
Deficiency & Toxicity
Food Sources: All whole foods like meats, milk, fruit, vegetables, grains, and
legumes, as well as, salt substitute
Deficiency
Adequacy
Toxicity
(<66% of DRI)
DRI: 4,700 mg/day
(UL is Not Established)
Approx. <990 mg/day
DRV: 3,500 mg
Bone & tooth: bone turnover
Cardio-Vascular:
hypokalemia, cardiac
arrhythmia, increased blood
pressure with increased risk
for heart attack and stroke
Neuro-Musccular: muscle
weakness
Other: glucose intolerance,
risk of kidney stones
Normal ICF volume and
function, nerve
transmission, muscle
contraction, and vascular
tone, blunts the rise in
blood pressure from
excess sodium, and
decreases kidney stone
reoccurrence
In renal (kidney) failure
only.
Cardio-Vascular:
hyperkalemia, cardiac
arrest
Neuro-Musccular:
muscle tetany
Potassium in Whole Foods
Adult DRI: 4,700 mg/day
Some Summary Points
• Adequate fluid intake is important for health and
optimal functioning.
• Dehydration has negative health effects.
• Fluid intake should support producing a clear
urine every 2 hours while awake.
• The electrolytes function to regulate fluid &
acid-base balance.
References for this presentation are the same as those
for this topic found in module 5 of the textbook