Transcript The Micronutrients and Water Part 3

The Micronutrients and Water
Part 3
Chapter 2
Electrolytes

Electrically charged particles dissolved in
body fluids
•
•
•
Sodium (Na+)
Potassium (K+)
Chlorine (Cl-)
Sodium

Roles in body

Modulate fluid
exchange within the
body's fluid
compartments
A
B
With equal numbers
of solute particles
on both sides of
the semipermeable
membrane, the
concentrations
are equal, and the
tendency of water
to move in either direction
is about
the same.
A
B
Now additional solute is
added to side B. Solute
cannot flow across the
divider (in the case of a
cell, its membrane).
A
B
Water can flow both ways
across the divider, but has
a greater tendency to move
from side A to side B,
where there is a greater
concentration of solute.
The volume of water
becomes greater on side
B, and the concentrations
on side A and B become
equal.
Stepped Art
Fig. 12-6, p. 405
Sodium

Roles in body

Regulate the acid and base qualities of body
fluids
 NaHCO3
Sodium

Roles in body

Establish the proper
electrical gradient
across cell membranes
Sodium

Sodium Roles in the Body

Assists in nerve impulse transmission


Action potential
Assists in muscle contraction

Action potential
Sodium

Dietary recommendations


Moderate intake of salt and sodium.
Excesses may aggravate hypertension

4500 mg – typical Western diet
Sodium

Sodium in Foods



Processed foods (75% of dietary sodium)
Table salt (15% of dietary sodium)
Moderate amounts in meats, milks,
breads and vegetables (10% of dietary
sodium)
Sodium

Sodium and Hypertension

Salt can have a great impact on high blood
pressure.




Restriction does help to lower BP.
Salt sensitivity - BP dependent on sodium intake.
Dietary Approaches to Stop Hypertension
(DASH) dietary plan to lower BP
Sodium and Bone Loss (Osteoporosis)

High sodium intake linked to calcium excretion.
Sodium

Sodium Recommendations


Minimum Adults: 500 mg/day
Adequate Intake (2004)





For those 19-50 years of age, 1,500 mg/day
For those 51-70 years of age, 1,300 mg/day
For those older than 70 years of age, 1,200 mg/day
The upper intake level for adults is 2,300
mg/day.
Maximum % Daily Value on food labels is set at
2400 mg/day.
Sodium

Deficiency



After vomiting, diarrhea, heavy sweating.
Symptoms are muscle cramps, mental
apathy, and loss of appetite.
Salt tablets without water induce
dehydration.
Sodium


Be careful of hyponatremia during
ultra-endurance athletic activities
Conservation

Kidneys – aldosterone
Chloride

Chloride Roles in the Body


Maintains normal fluid and electrolyte
balance
Part of hydrochloric acid found in the
stomach

Necessary for proper digestion
Chloride

Essential nutrient in fluid balance.


Extracellular anion (Cl-)
It is associated with sodium


Rises and falls with sodium levels
Regulated (indirectly) by aldosterone
(sodium)
Chloride

Chloride Recommendations and
Intakes

Recommendations

Adequate Intake (2004)




For those 19-50 years of age, 2,300 mg/day
For those 51-70 years of age, 2,000 mg/day
For those older than 70 years of age, 1,800 mg/day
Upper intake level is 3,600 mg/day
Chloride

Chloride Deficiency


Deficiency is rare (sodium)
Losses:



Vomiting,
Diarrhea or
Heavy sweating.
Potassium



An electrolyte associated with fluid
balance.
Associated with hypertension.
It is found in fresh foods—mostly fruits
and vegetables.
Potassium

Potassium Roles in the Body


Maintains normal fluid and electrolyte
balance
Assists in nerve impulse transmission
and muscle contractions
Potassium

Potassium Recommendations and
Intakes

Adequate Intake (2004)



For all adults, 4,700 mg/day
Fresh foods are rich sources.
Processed foods have less potassium
Potassium

Potassium and Hypertension


Low potassium intakes increase blood
pressure.
High potassium intakes prevent and
correct hypertension.

K may make blood vessels less sensitive to
catecholamines – vasoconstriction
Water

Constitutes 40-70% of the total body
mass.
•
•
Muscle contains 65-75% water by weight.
Water represents only about 50% of the
weight of body fat.
Water
•
Of the total body water


62% exists in the intracellular
compartment
38% in the extracellular compartment
•
plasma, lymph, and other fluids outside the
cell.
Water




Provides structure and form to the
body
Regulates temperature
Provides a medium for substances to
interact chemically
Transports oxygen and nutrients
Water Intake

The average daily water intake comes
from
•
•
•
Liquid – about 1.2 L
Food – about 1.0 L
Metabolic water – about 0.3 L
Water Output

Daily water loss occurs from
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Urine – about 1-1.5 L
Insensible perspiration – about 0.50-0.70 L
Water vapor in expired air – about 0.25-0.30 L
Feces – about 0.10 L