Chapter Nine: Water and Minerals

Identify the functions of water Describe the process by which the

body regulates water intake and water excretion

Identify normal causes of water loss List causes of additional (less usual)

water losses

Chapter Eight, Cntd. Name the major minerals and the

functions and deficiencies of those at risk Explain osteoporosis and the risk factors

that contribute to its development Name the trace minerals and their

functions and deficiencies of those at risk Explain how the use of alcohol affects

nutritional status

Water and Body Fluids Adult body is comprised of 60% water Water functions

Transports nutrients and waste products Participant in chemical reactions

(metabolism) Solvent for water soluble nutrients Maintains blood pressure and body

temperature

Water Functions, Cntd. Lubricant and cushioning for joints Shock absorber for eyes, spinal, and

placenta

Water Balance Regulators

Thirst—outward sign of dehydration Diminished with age

Hypothalamus monitors lack or excess Triggers pituitary to release ADH

(antidiuretic hormone) when salts are too high and volume of blood or blood pressure is too low

Kidneys respond by excreting or withholding fluids

Water Losses Losses normally occur from:

Urine—water required to excrete urine and body wastes

Lungs as vapor Feces Skin in the cooling process About 2½ quarts per day

Recommended Water Intake 8-12 cups per day (pale yellow urine

indicates appropriate dilution) Water, milk and juices are best

sources Alcoholic beverages and those

containing caffeine act as diuretics Fruits, vegetables, meats and cheese

also contribute to water intake

Fluid and Electrolyte Balance Mineral salts when dissolved in water

contain electrical charges and are known as electrolytes

Electrolytes and water are the most vital to life—electrolytes hold water in compartments where needed

Electrolytes outside the cell are sodium and chloride

Electrolyte inside the cell is potassium

Electrolyte and Fluid Balances Balances can be upset by large fluid losses

Vomiting Diarrhea Heavy sweating Fever Burns Wounds causing blood loss

Electrolytes also help maintain the acidity pH of body fluids

Major Minerals Needed in larger amounts in the body Sodium:

Principle electrolyte in the extracellular fluid outside the cell

Maintains acid-base balance—muscle contraction and nerve transmission

Sources: processed foods, salt added while cooking (select iodized salt)

Major Minerals, Cntd. Sodium

Average intake is about 3300 mg and Daily Value recommendation is 2400 mg

Risks of too much are high blood pressure or hypertension

Choose and prepare foods with less salt—U.S. Dietary Goal

Major Minerals, Cntd. Chloride:

Extracellular electrolyte Usually associated with either sodium

or potassium Part of HCL acid found in the stomach Best source in table salt

Major Minerals, Cntd. Potassium

Principal charged electrolyte found inside the cell

Critical to keeping the heartbeat steady Diets low in potassium can contribute to

elevated blood pressure Sources: fresh food of all kinds,

especially fruits and vegetables—oranges & bananas

Major Minerals, Cntd. Calcium

Necessary for growth of a healthy skeleton and prevention of bone disease later in life

Most abundant mineral in the body 99% of calcium found in the bones and

teeth—provides rigidity 1% found in body fluids—vital to life

Regulate muscle contractions Transmits nerve impulses

Major Minerals, Cntd. Blood clotting Cofactor to several enzymes

Deficiencies: Osteoporosis

Porous, thin, fragile bones found mostly in older women

Can also correlate with high blood pressure

Absorption can vary between 30-75%

Major Minerals, Cntd. Sources:

Best are in the daily group (2-3 cups per day of fluid milk or their equivalents)

Vegetables: mustard greens, kale, parsley, watercress, and broccoli

Meat group: particularly sardines, including bones and poultry

Major Minerals, Cntd. Phosphorus 2nd most abundant mineral in the

body Excess in the diet can cause

excretion of calcium—carbonated beverages and high protein diet, especially from meat sources

Trace Minerals Needed in smaller amounts in the

body Iron:

Absorption is limited—10-15% absorbed from dietary sources—can increase with good Vitamin C sources eaten together

Function: component of the protein hemoglobin that carries oxygen from the lungs to tissues

Trace Minerals, Cntd. Deficiency—Iron deficiency anemia—

most prevalent in children and pre-menopausal women

RDA is 10-15 mg per day Sources: Most absorbable sources

are meats, poultry and fish, esp. organ meats; plant sources are less absorbable

Toxicity: can cause death, especially in small children

Trace Minerals, Cntd. Zinc:

Multiple metabolic functions Deficiency can cause growth retardation

and affects immune function Sources are high protein foods

Iodine: Integral part of the thyroid hormone,

thyroxin

Trace Minerals, Cntd. Deficiency causes mental and

physical retardation Problem in underdeveloped countries

who don’t have access to iodized salt Sources: Iodized salt or foods grown

in iodine rich soil; high mountain areas have little in the soil

Trace Minerals, Cntd. Fluoride

Necessary for normal bone and tooth development

Teeth are more resistant to decay Sources: drinking water either

naturally or from fluoridated water

Nutrition and Alcohol Abuse Sources of Alcohol:

Wine, wine coolers, beer, and hard liquor

Nutritional deficiencies can result from Depression of appetite—less food eaten Interference with digestion, absorption,

metabolism and excretion of nutrients Vitamins and minerals necessary for normal

metabolism interfered with so fewer nutrients are available from food

TEST QUESTIONS Water is involve in all of the

following EXCEPT: A. Regulation of body temperature B. conversion of lipids to amino acids C. Lubricant around joints D. Solvent for minerals and vitamins

Test Questions Which of the following body

processes in NOT dependent upon the presence of calcium in the body fluids? A. Blood clotting B. Muscle contraction C. Transmission of nerve impulses D. Transportation of oxygen in the

bloodstream

Test Questions A deficiency of _________ is one of

the world’s most common preventable causes of mental retardation

A. Zinc B. Selenium C. Magnesium D. Iodine