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

Intracellular

67%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% Adults15% Infants

Fluid Sources and Losses (in liters)

Importance of Water

Moments without oxygenDays without waterWeeks 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

20% water loss is fatal

How to Become Dehydrated

• Intake of caffeine• Intake of alcohol• Diuretic medications• Sweating• Heat exposure

Effects of Dehydration on Health

Chronic Mild Dehydrationis linked to:

• Reduced – Physical Performance– Mental Performance– Salivary Gland Function

• 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 Body100% 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

Met

abol

ic

H 2O

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

(<66% of DRI)

Approx. <990 mg/day

Adequacy

DRI: 1500 mg/day

DRV: 2400 mg

Toxicity

(>UL)

>2,300 mg/day

Cardio-Vascular: hyponatremia, cardiac failureCentral Nervous System: mental apathy, weaknessGI System: loss of appetiteNeuro-Musccular: muscle cramping, skeletal muscle cell injuryOther: 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 strokeOther: 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

(<66% of DRI)

Approx. <1520 mg/day

Adequacy

DRI: 2,300 mg/day

(3,800 mg NaCl)

RDI: 3,400 mg

Toxicity

(>UL)

>3,500 mg/day

(5,800 mg NaCl)

Bone & tooth: growth failure in childrenCentral Nervous System: mental apathyGI System: loss of appetiteNeuro-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

(<66% of DRI)

Approx. <990 mg/day

Adequacy

DRI: 4,700 mg/day

DRV: 3,500 mg

Toxicity

(UL is Not Established)

Bone & tooth: bone turnoverCardio-Vascular: hypokalemia, cardiac arrhythmia, increased blood pressure with increased risk for heart attack and stroke Neuro-Musccular: muscle weaknessOther: 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