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Chapter 10
WATER AND THE
ELECTROLYTES
Water
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Water is an essential nutrient that must be
consumed for survival.
Water is a polar solvent in the body.
The polarity of water comes from hydrogen
and oxygen.
Blood is 90% water.
Blood transports oxygen and nutrients to cells
and removes carbon dioxide and waste
products.
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Water
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Water functions as a lubricant and cleanser.
Tears wash away dirt, synovial fluid
lubricates joints, saliva assists in chewing,
tasting and swallowing and spinal fluid
protects against shock.
Water assists in regulating body temperature
by holding onto heat and changing
temperature slowly.
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Water molecule
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Hydrolysis and Condensation
Reactions
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Water and pH Balance
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Water in the Body
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About two-thirds of body water is found inside cells. Water
inside cells is called intracellular fluid.
Extracellular fluid is found outside the cells.
Interstitial fluid consists of lymph, blood plasma and
extracellular fluid.
Intracellular fluid has the highest concentration of protein,
extracellular fluid has less, and interstitial fluid has the
lowest concentration of protein.
Extracellular fluid has the highest concentration of sodium
and chloride and a lower concentration of potassium.
Intracellular fluid has the lowest concentration of sodium
and the highest concentration of potassium.
The fluid pressure of blood against the blood vessels is
blood pressure.
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Osmosis
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Need for Water in the Body
Compared to Intake
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Resources for Water in the Diet
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Bottled Water
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Health Canada defines bottled water as water intended
for human consumption that is packed in a sealed
container. It can be derived from natural sources such as
springs and aquifers or from municipal water supplies.
One quarter to one third of Canadian households use
bottled water as their main source of drinking water.
70% choose bottled water because of taste and 25%
perceive bottled water as safer and healthier.
Similar standards are set by federal, provincial and/or
municipal agencies for both bottled and tap water.
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Thirst Mechanism
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Antidiuretic Hormone
Assists in
Fluid Intake
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Consequences
of Dehydration
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Electrolytes: Sodium, Potassium
and Chloride
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The correct combination and amounts of
electrolytes are essential for life.
Distribution of electrolytes affects the
distribution of water throughout the body.
Sodium, potassium and chloride are the
principle electrolytes in body fluids.
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Summary of Water and the Electrolytes
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Sodium Intake of Canadians
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CCHS collected information on Canadians’
intake of sodium and potassium. Sodium
intake was expressed as the percentage of
the population consuming above the UL.
90.2% of males (>19 years) above the UL
65.7% of women (>19 years) above the UL
A concern is that excessive sodium intake is
associated with increased risk for
hypertension.
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Sodium Intake of Canadians (continued)
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Hypertension
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Hypertension is a serious public health
concern in Canada.
20% of adult Canadians have hypertension
(140/90 mm or greater).
20% of adult Canadians have
prehypertension (120/80–139/89 mm).
It is estimated that 17% of Canadians do not
know they have hypertension.
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Hypertension and Diet
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The lower the amount of sodium in the diet,
the lower the blood pressure.
The average intake of sodium in the
Canadian diet is 3400 mg. A reduction in
sodium by 1000 to 1500 mg will reduce blood
pressure in those with and without
hypertension.
The Sodium Reduction Strategy for Canada
recommends that Canadians reduce their
sodium intake to less than 2300 mg/day.
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Hypertension and Diet (continued)
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Diet and lifestyle are both involved in
regulating blood pressure.
Maintaining a desirable body weight, staying
active and limiting alcohol consumption will
assist in keeping blood pressure within the
normal range.
Consuming a diet described in Canada’s
Food Guide or the Dash Diet will also help in
keeping blood pressure within the normal
range.
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Hypertension and Diet (continued)
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Hypertension and Diet (continued)
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Hypertension and Diet (continued)
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Food labels list the sodium-containing ingredients in the
ingredient list.
The Nutrition Facts panel gives the total amount of
sodium in milligrams and as a percentage of Daily Value
to help buyers compare food products.
Food labels can also include nutrient content claims
relating to salt or sodium.
Hypertension Canada recommends that Canadians
consume foods containing 200 mg of sodium per serving
but avoid foods that contain more than 400 mg of sodium
per serving.
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Hypertension and Diet (continued)
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Hypertension and Diet (continued)
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Potassium Intake of Canadians
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The average Canadian diet contains 2500 to 3500
mg of potassium/day, which is well below the
recommendation of 4700 mg/day.
Fruits and vegetables are the best source of
potassium. Canadians do not meet the number of
servings of fruits and vegetables recommended by
Canada’s Food Guide. This is the reason for their
low potassium intake.
Following Canada’s Food Guide and Dash Diet
recommendations would result in a potassium intake
of 8000 to 10,000 mg/day.
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Potassium Intake of Canadians (continued)
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Copyright
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