Chapter 9- Water and Minerals by leader6

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									                     Chapter 9- Water and Minerals
Water
      Water acts as a solvent- it dissolves many body compounds such as sodium
       chloride (table salt)
      Water is the perfect medium for body processes because it enables chemical
       reactions to occur
      Forms the greatest component of the human body, making up 50% to 70% of the
       body’s weight (about 10 gallons)
      Lean muscle tissue contains about 73% water
      Adipose tissue is about 20% water
      An adult can survive for about 8 weeks without eating food but only a few days
       without drinking water

WATER IN THE BODY-INTRACELLULAR AND EXTRACELLULAR FLUID
   Water inside cells forms part of the intracellular fluid (fluid within the cell)
   When water is outside cells or in the bloodstream, it is part of the extra cellular
    fluid (the outside cells)
   Water shifts freely in and out of cells
   If blood volume decreases, water can move from the areas inside and around cells
    to the bloodstream to increase blood volume
   Blood volume increases, water can shift out of the bloodstream into c3ells and the
    surrounding areas, leaving to edema
   The body controls the amount of water in the intracellular and extra cellular
    compartments mainly by controlling ion concentrations
   Ions are minerals that have electrical charges, and so are called electrolytes
   Water is attracted to sodium, potassium, chloride, phosphate, magnesium and
    calcium
   By controlling the movements of ions in and out of the cellular compartments
   The body maintains the appropriate amount of water in each compartment using a
    process called osmosis
   Overall, where ions go, water follows

WATER CONTRIBUTES TO BODY TEMPERATURE REGULATION
   Water temperature changes slowly because it has a great ability to hold head
   When overheated, the body secretes fluids in the form of perspiration, which
    evaporates through skin pores
   To evaporate water, heat energy is required
   As perspiration evaporates, heat energy is taken from the skin, cooking it in the
    process
   About 60% of the chemical energy in food is turned directly into body heat
      the other 40% is converted to forms of energy cells can use, and almost all of that
       energy eventually leaves the body in the form of heat
      if this heat could not be dissipated, the body temperature would rise enough to
       prevent enzyme systems from functioning efficiently
      perspiration is the primary way to prevent this rise in body temperature
      too cool efficiently, perspiration must be allowed to evaporate
      evaporation of perspiration occurs quickly when humidity is low
      this is why humans can cool off and therefore tolerate hot, dry climates far better
       than they do not, humid climates

WATER HELPS REMOVE WASTE PRODUCTS
   water is an important vehicle for transporting waste products from the body
   most unusable substances in the body can dissolve in water and exit the body
    through the urine
   urea is a major body waste product
   this by-product of protein metabolism contains nitrogen
   the more protein we eat the more nitrogen we excrete-in the form of urea-in the
    urine
   likewise the more sodium we consume, the more sodium we excrete in the urine
   the amount of urine a person needs to produce is determined primarily by excess
    protein and salt intake
   a typical urine volume is about 1 liter or more per day
   a somewhat greater urine output than that is fine, but less (especially less than 500
    mL) forces the kidneys to form very concentrated urine
   the simplest way to determine if water intake is adequate is to observe the color of
    one’s urine
   whereas urine should be clear or pale yellow, concentrated urine is very dark
    yellow in color
   the heavy ion concentration in turn increases the risk of kidney stone formation in
    susceptible people
   kidney stones are formed from minerals and other substances that have
    precipitated out of the urine and accumulated in kidney tissues

HOW MUCH WATER DO WE NEED PER DAY
   the adequate intake for total water intake is 2.7 liters for adult women and 3.7
    liters for adult men
   coffee, tea, and soft drinks often contain caffeine, which increases urine output
   much of the water needed is used to produce urine
   thirst mechanism can lag behind actual water loss, however, during prolonged
    exercise and illness, as well as in one’s older years
   athletes especially should monitor fluid status
   once the body registers a shortage of available water, it increases fluid
    conservation
   2 hormones that participate in this process are antidiuretic hormone and
    aldosterone
      Antidiuretic hormone to force the kidneys to conserve water
      Aldosterone, which signals the kidneys to retain more sodium and, in turn, more
       water
      By the time a person loses 1-2% of body weight in fluids, he or she will be thirsty
      At a 4% loss of body weight, muscles lose significant strength and endurance
      At a 20% reduction, coma and death may soon follow
      Too much water can also lead to ill health, such as low blood electrolyte
       concentrations
      Blurred vision is one resulting symptom

Minerals- An Overview
      Some minerals work as cofactors, which enable enzymes to function.
      They also contribute too many body compounds (iron is a component of red blood
       cells).
      Sodium, potassium, and calcium aid in the transfer of nerve impulses throughout
       the body.
      Body growth and development also depend on certain minerals (calcium).
      Water balance requires sodium, potassium, calcium, and phosphorus.
      If we require greater than 100 milligrams of a mineral per day, it is considered a
       major mineral; otherwise, it is considered a trace mineral.

Mineral Bioavailability

The concept of absorbing variable amounts of a nutrient from food sources is called
bioavailability.

Overall, minerals from animal products are better absorbed than those from plants
because binders and fiber are not present to hinder absorption.

The mineral content of plants greatly depends on mineral concentrations of the soil in
which they are grown.

The more refined a plant food, like white flour, the lower its content of minerals.

Oxalic acid (oxalate): an organic acid found in spinach, rhubarb, and other leafy green
vegetables that can depress the absorption of certain minerals present in the food, such as
calcium.

Phylate: components of fiber that limits the absorption of some minerals by binding to
them.

Mineral toxicities
An excessive mineral intake can have toxic results, especially with the trace minerals,
such as iron and copper. Supplements pose the biggest threat for mineral toxicity because
they exceed current standards for mineral needs, especially those that supply more than
100% of the daily values.

Sodium: The body absorbs almost all the sodium that gets eaten. It is the major ion
in extra cellular fluid and a key factor in retaining body water.

Only when weight loss from sweat is over 2-3% of the total body weight (5 or 6
pounds) should sodium losses raise concern. Salting foods is sufficient in restoring
body sodium for most people.

The more processed and restaurant food one consumes, generally the higher the
sodium intake.

The daily value for sodium is 2300 milligrams.

Potassium: it performs many of the same functions as sodium (fluid balance and
nerve impulse transmission). The difference is it operates inside, rather than outside
of the cells. Intracellular fluids contain 95 % of the potassium in the body. Low
blood potassium is a life threatening problem, causing heart beat irregularity,
decreasing the blood pumping capacity.

Major contributors to the diet include: milk, potatoes, beef, coffee, tomatoes, and
orange juice.

Adequate intake is about 4700 milligrams.

Taking diuretics can deplete the body’s potassium (caffeine in coffee).

Chloride: a component of the acid produced in the stomach. They are used during
immune responses as white blood cells attack foreign cells. We consume most
chloride as salt added to foods.

Calcium: More than 99% of the calcium in the body is used to strengthen bones and
teeth. This calcium represents 40% of all the minerals present in the body.

The calcium circulating in the bloodstream supplies the calcium needs of body cells.

The amount of calcium in the body depends greatly on its absorption from the diet.
It requires an acidic environment in the intestinal tract to be absorbed efficiently (it
is absorbed in the upper level of the tract, where stomach acid lingers primarily).

Adults absorb about 25% of the calcium in the foods eaten, but during time when
the body needs extra calcium (infancy and pregnancy), absorption increases to as
high as 60%.
Factors enhancing calcium absorption:

A. the blood levels of parathyroid hormone.
B. the presence of glucose and lactose in the diet.
C. the flow of digestive contents through the intestine.

What limits calcium absorption?

A. acid in fiber from grains.
B. excess phosphorus in the diet.
C. polyphenols in tea
D. vitamin D deficiency
E. diarrhea
F. old age

We have excellent hormonal systems to control blood calcium levels, so a normal
value can be maintained despite an inadequate calcium intake, but the bones pay
the price…they are the calcium bank that can be added or withdrawn. The bone
loss caused from low calcium absorption from the bank proceeds slowly.

By not meeting calcium needs, people (especially women) are setting the stage for
future bone fractures.

Functions of calcium:

1. blood clotting and muscle contraction: if blood calcium falls below a critical point,
muscles cannot relax after contraction. The body stiffens and shows involuntary
twitching.
2. Nerve transmission: calcium assists the flow of neurotransmitters to prevent
nerve function failure.
3. Cellular metabolism regulation: enzyme and hormone activity helps to aid
cellular metabolism.

The lack of calcium to perform any of these is called TETANY.

Calcium also reduces colon cancer risk and lowers LDL cholesterol.

Calcium sources

75% of the calcium in North American diets is from dairy
products. (The exception is cottage cheese: calcium is lost during production).
If you don’t like dairy, use leafy greens, broccoli, sardines, salmon, fortified OJ and
breakfast cereals.
The most nutrient-dense source of calcium is nonfat milk.

The adequate intake for calcium is 1000-1200 milligrams per day; while upper levels
are 2500 milligrams (greater intake increases the risk for some forms of kidney
stones

People who do not like milk will take calcium supplements. Calcium carbonate is the
most common supplement used (calcium based antacid tablets). There is some
evidence that calcium supplementation may decrease zinc absorption. Food sources
are the best choice for absorption.

Yogurt is the highest food source of calcium.

Osteoporosis- loss of bone calcium. High risks for this include a poor dietary intake
of calcium. There are 1.5 million bone fractures per year in the U.S., usually in the
hip, spine, or wrist.

The slender inactive woman who smokes is most susceptible to osteoporosis.

There are 2 primary bone structure types:

A. cortical bone: dense, compact bone that comprises the outer surface and shafts of
bone, also called compact bone.
B. trabecular bone: spongy inner bone found in the spine, pelvis, and ends of bones,
especially in heavily stressed areas, such as joints.

Bone mass strength depends on bone mass and bone mineral density.

The more bone there is, and the more densely packed bone crystals there are in the
bone, the stronger the bone structure.

The ultimate amount of bone built by a person is clearly dependent on gender, race,
and family patterns. There is also a genetic pattern of the degree of calcium
absorption. Men have higher bone mass than women, and blacks have heavier
skeletons than whites

Bone loss begins at age 30 and proceeds slowly to menopause (around 50), and then
it speeds up.

Osteoporosis prevention involves 3 main elements

-meeting calcium needs
-since the hormones of regular menstruation contribute to bone maintenance in
young women, any sign of menstrual irregularities is reason to see a doctor.
-an active lifestyle that includes weight bearing activity.
99% of calcium in the body is found in bones.

Phosphorous

The body absorbs phosphorus quite efficiently. About 85% of the body’s phosphorus is
inside bone (provided by milk, cheese, meat, and bread). Vitamin D enhances phosphorus
absorption (the same for calcium).

Phosphorus is a component of enzymes, DNA (genetic material), and compounds of
energy metabolism.

Magnesium

_important for nerve and heart function and aids many enzyme reactions. Rich sources
for magnesium are plant products, such as whole grains.

The refined grain products that dominate the diets of many North Americans are poor
sources of this mineral.

Milk, meat, coffee, broccoli, potatoes, squash, beans, nuts, and seeds are good sources of
magnesium.

Sulfur

Sulfur helps in the balance of acids and bases in the body and is an important part of the
liver’s drug detoxifying pathways. It is usually supplied by proteins




Trace Minerals
      Trace minerals are also called micro minerals
      Although we need 100 milligrams or less of each trace mineral daily, they are just
       as essential to good health as are major minerals
      Evidence of trace minerals is still unfolding
      1961 researchers linked dwarfism in middle eastern villagers to a zinc deficiency

IRON (FE)
   iron deficiency is still one of the most common nutrient deficiencies worldwide
   iron is the only nutrient for which young women have a greater RDA than do
     adult men
   the body uses several mechanisms to regulate iron absorption
      controlling absorption is important because our bodies cannot easily eliminate
       excess iron once it is absorbed
      overall, iron absorption depends on its form in the food, the body’s need for it,
       and a variety of other factors
      the form of iron in foods especially influences how much is absorbed
      about 40% of the total iron in animal flesh is in the form of hemoglobin and
       myoglobin
      the heme iron is absorbed about two or three times more efficiently than the
       simple elemental iron, called nonheme iron
      consuming heme iron and nonheme iron together increases nonheme iron
       absorption
      overall, eating meat with vegetables and grain products enhances the absorption
       of all nonheme iron present
      vitamin C in amounts of about 75 milligrams can increase nonheme iron
       absorption
      so one should consider drinking a glass of orange juice when taking an iron
       supplement
      overall, the most important factor influencing nonheme iron absorption is the
       body’s need for it
      iron needs are increase during pregnancy and growth
      at high altitudes, the lower oxygen concentration of the air causes an increase in
       the hemoglobin concentration of blood and thus an increase in iron needs

FUNCTIONS OF IRON
   iron is part of the hemoglobin in red blood cells and myoglobin in muscle cells
   if neither the diet nor body stores can supply the iron needed for hemoglobin
     synthesis, the number of red blood cells decreases in the bloodstream
   physicians use both the percentage of red blood cells (called hematocrit) and the
     hemoglobin concentration to asses iron status
   when hematocrit and hemoglobin fall, an iron deficiency is suspected
   in severe deficiency, hemoglobin and hematocrit fall so low that the amount of
     oxygen carried in the bloodstream is decreased
   such a person has anemia, defined as a decreased oxygen-carrying capacity of the
     blood
   while there are many types of anemia, iron-deficiency anemia is the major type
     worldwide
   women are also very vulnerable during childbearing years from blood loss during
     menstruation

SOURCES
   animal sources contain some heme iron, the most bioavailable form
   the major iron sources in the adult diet are ready-to-eat breakfast cereals, animal
    products and bakery items, such as bread
   milk is a very poor source of iron
      a common cause of iron-deficiency anemia in children is an over reliance on milk,
       coupled with an insufficient meat intake
      total vegetarians (vegans) are particularly susceptible to iron-deficiency anemia
       because of their lack of dietary heme iron
      the higher RDA for young and middle-age women is primarily because of
       menstrual blood loss

UPPER LEVEL FOR IRON
   the upper level for iron is 45 milligrams per day
   although iron overload is not as common as iron deficiency, it can be a serious
     result of misuse because it can easily build up in the body and lead to toxic
     symptoms

Zinc

Most people worldwide rely on cereal grains for their source of protein, and calories, but
adequate zinc absorption becomes a problem.

Up to 200 enzymes (including the one that aids in metabolizing alcohol), require zinc for
optimal activity.

Zinc aids in DNA synthesis, protein metabolism, immune function, development of
sexual organs, storage, release, and function of insulin, cell membrane structure and
function, and it aids in the production of an enzyme that keeps cells from damaging.

Animal foods supply almost half of an individual’s zinc intake.

Many companies are singing the praises of zinc as a cold remedy. Even though studies
showed that cold symptoms went away in half the time, nausea was a side effect, and it
showed that there is different bioavailability of zinc, and some zinc pills were more
potent.


Selenium

Its best role is aiding the activity of the enzyme that participates in reducing the damage
that free radicals do to cell membranes.

Vitamin E works together with selenium by donating electrons to electron seeking
compounds.

Selenium deficiency symptoms include muscle pain and certain form of heart damage.

Sources are fish, organ meats, eggs, and shellfish

Chromium
It aids in the action of the hormone insulin, and the maintenance of glucose uptake
into cells (a major prevention of diabetes).

A deficiency is characterized by impaired blood glucose control and elevated blood
cholesterol and triglycerides.

Egg yolks, whole grains, organ meats, mushrooms, nuts, and beer are good sources.

								
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