Transcript 413 PHG lecture

Minerals
By EBTESAM ALSHEDDI
Small, naturally occurring, inorganic,
chemical elements
 Regulate body processes
 Give structure to things in the body
 No calories (energy)
 Cannot be destroyed by heat
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What are minerals?
Categories of minerals
• Major minerals are needed in the diet in amounts greater than
100 mg per day or are present in the body in amounts greater
than 0.01% of body weight.
• Trace minerals are required in the diet in amounts less than
100 mg per day or are present in the body in amounts less than
0.01% of body weight.
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Major minerals
◦ Calcium
◦ Phosphorus
◦ Magnesium
◦ Electrolytes (sodium,
chloride, potassium)
◦ sulfur
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Trace minerals
◦ Chromium
◦ Copper
◦ Flouride
◦ Iodine
◦ Iron
◦ Manganese
◦ Selenium
◦ Zinc
The Minerals in Your Body
Figure 12.1
Minerals in the Diet
Copyright 2010, John Wiley & Sons, Inc.
Major Minerals
Copyright 2010, John Wiley & Sons, Inc.
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.
Copyright 2010, John Wiley & Sons, Inc.
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Sodium is the principal
cation in extracellular
fluids
functions include:
 osmotic equilibrium
(fluid balance)
 acid-base balance
 carbon dioxide
transport
 cell membrane
permeability
 muscle contraction
 Nerve impulse
transmission
Sodium (Na)
food sources: table
salt, salty foods
(potato chips,
pretzels, etc.), baking
soda, milk.
 RDA for adults: 1.1 to
3.3 gm/day
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deficiency:
• dehydration
• acidosis
• tissue atrophy
• Mental confusion
• Muscle cramps
excess:
edema
hypertension
Potassium (K)
•The principal cataion in
intracellular fluid
•functions:
Deficiency (hypokalemia):
• Buffer constituent
• Acid-base balance Muscle weakness, Paralysis, Mental confusion
and Irregular heart beat.
• Water balance
 causes:
• Muscle contraction
• Nerve impulse
 increased renal excretion (diuretics)
transmission
 primary aldosteronism
 severe vomiting and diarrhea
 cutaneous losses via perspiration
•Food sources:
• Excess(hyperkalemia):
vegetables, fruit
(bananas), whole grains, Muscle weakness, Irregular heart beat, vomiting
• causes:
meat, milk
sudden increased intake
•RDA for adults: 1.5 - 4.5
severe tissue trauma and burns
gm/day
acute and chronic acidosis
Chloride (Cl)
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An essential anion
Closely connected with sodium in foods, body tissues
and fluids and excretions
readily absorbed along with sodium
important for osmotic balance, acid-base balance, in the
formation of gastric HCl, muscle contraction and nerve
impulse transmission
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Deficiency of chloride:
 hypochloremic alkalosis
 hypovolemia
 pernicious vomiting
 psychomotor
disturbances
Major Minerals and Bone Health
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Minerals make up the crystalline structure
that gives strength to bones and teeth
◦ Major minerals
 Calcium, phosphorus, and magnesium
◦ Trace mineral
 Flouride
Minerals Make Up Bones and Teeth
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the most abundant of the minerals
the 5th most abundant element in
the body
needed by all cells
found in largest amounts in bones
(99%)
Calcium (Ca)
Three hormones involved in regulation
 Vitamin D3
 from kidney
 Parathyroid hormone (PTH)
 from parathyroid gland
 Calcitonin
 from thyroid gland
PTH and Vitamin D3 act to increase plasma Ca, while calcitonin
acts to decrease plasma Ca
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function of calcium:
◦ structural unit of bones and teeth
◦ contraction and relaxation of muscles
◦ stabilizes nervous tissue
 low calcium --- irritable nerves --- tetany
 high calcium --- depresses the nervous irritability
◦ required for blood clotting
◦ activates various enzymes
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RDA
◦ adult: 800 mg/day
◦ pregnancy and lactation: 1200 mg/day
Deficiency
Osteoporosis, convulsion
and heart failure .
Toxicity
Mineral imbalance, shock,
kidney failure, mental
confusion
Calcium
-parathormone (PTH) by the
parathyroid gland and
thyrocalcitonin secreted by the
thyroid gland maintain serum
levels
 -with decreased serum calcium
levels, PTH increases and causes
transfer of calcium from bone to
blood to increase serum levels
 -decreased levels also cause
kidney to reabsorb calcium more
efficiently (might normally be
excreted in the urine) and to
increase intestinal absorption
 -when blood levels are increased,
calcitonin acts by the opposite
mechanisms as PTH to decrease
serum levels
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Regulation of Calcium
Homeostasis
Osteoporosis Risk
Copyright 2010, John Wiley & Sons, Inc.
Gender and Bone Mass
Copyright 2010, John Wiley & Sons, Inc.
Phosphorus
Phosphorus is the second most abundant mineral in the
body
 required in many phases of metabolism
 foods rich in calcium are also richest in phosphorus (milk,
cheese, eggs, beans, fish)
RDA for phosphorus is established on the basis of a 1:1
relationship with calcium
Adults: 800 mg/day
Pregnancy and lactation: 1200 mg/day
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Fluid balance
Regulate energy metabolism
Component of bones, teeth
Part of DNA, RNA (cell growth, repair)
Deficiency
Muscle weakness, bone pain
and dizziness.
Toxicity
Muscle spasm, convulsion
and low blood calcium
Magnesium
-Function
bone, muscle contractility, nerve
excitability
-antagonistic to calcium
--in a muscle contraction, Mg relaxes,
and calcium contracts
--low Mg can cause pregnancy induced
HTN
 Part of 300 enzymes (regulates body
functions)
 Best sources are all green plants
(chlorophyll); meats
 RDA: 350 mg/day
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Toxicity
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-respiratory depression,
apnea
-CV—hypotension,
cardiac arrest,
-GI—N/V
-neuromuscular—
paresthesias, confusion,
coma, hyporeflexia,
paralysis
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◦ pregnancy and lactation: 450 mg
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Deficiency
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-anorexia, growth failure, cardiac and neuromuscular changes—
weakness, irritability, mental derangement
 -tetany, muscle cramps
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Component of amino acids
◦ cystine, cysteine, and methionine for bioactive
and structural proteins
 wool contains about 4% sulfur
Chondroitin sulfate is a constituent of
cartilage
 Deficiency is related to protein deficiency
 Sulfur is widely available in meat, eggs,
milk, cheese, legumes, and nuts.
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Sulfur
Summary of Calcium, Phosphorus,
Magnesium and Sulfur
Copyright 2010, John Wiley & Sons, Inc.
The Trace Elements
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Deficiency
◦ Aneamia
◦ neutropenia
◦ bone demineralization
◦ failure of
erythropoiesis
Toxicity
Nausea, vomiting and
diarrhea.
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sources
Copper (Cu)
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important trace
mineral
component of several
enzymes
Increases iron
absorption
needed to form
hemoglobin and
collagen
 liver, shellfish, whole
grains, cherries,
legumes, nuts
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Considered essential because of its
beneficial effect on tooth enamel
Benefits include: less dental caries, stronger
bones, reduction in osteoporosis and
calcification of the aorta
In large quantities it is deleterious to teeth;
dental fluorosis: pitting, chalky, dull white
patches and mottling of teeth
1 to 2 parts per million is adequate for
drinking water
Main sources include drinking water and plants
(spinach, lettuce, onions)
Average daily intake: 1.5 – 4.0 mg/day
Fluoride
Iodine
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Iodine is necessary for :
The formation of thyroid hormones (T-4
and T-3)
Temperature regulation
deficiency of iodine (hypothyroidism) is
manifested by a goiter (enlargement of
the thyroid gland)
salt water fish and seaweeds are a good
source of iodine
to prevent the development of endemic
goiter, table salt has been spiked with
sodium iodide
Chromium
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Cr III may act as a cofactor for insulin,
enhancing glucose utilization
deficiency leads to impaired glucose tolerance
(glucose tolerance factor)
sources: corn oil, whole-grain cereals, clams,
drinking water (variable)
forms a coordination complex with micotinic
acid and the amino acids glycine, glutamate
and cysteine
chromium may have a role in type 2 diabetes
RDA: 0.05 – 0.2 mg
frequently available in pharmacies as chromium
picolinate
Manganese (Mn)
Deficiency leads to:
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Weight loss
Transient dermatitis
Nausea and vomiting
Changes in hair color
Reduced bone density
Impaired lipid and glucose
metabolism
Manganese is an activator of
several different enzymes.
Synthesis of protein found in
bone and cartilage
Toxicity
• Impairment of neuromuscular
system
Sources: blueberries, wheat
bran, beet greens, lettuce,
legumes, fruit
RDA: 2.5 – 5.0 mg
heme iron
◦ meats
◦ poultry
◦ fish
20-23% of heme-iron
is absorbable
Iron
non-heme iron
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vegetables
fruits
legumes
nuts
breads and cereals
only ~ 3% on non
heme iron is
absorbed
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occurs in upper part of small intestine
about 10% of food iron is absorbed
requires gastric HCl (releases ionic iron)
also requires copper
ferrous is better absorbed than ferric form
Fe++ forms chelates with ascorbic acid,
certain sugars and amino acid
Iron absorption
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stored in 2 forms:
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stored in liver, spleen, bone marrow,
intestinal mucosal cells and plasma
 ferritin (a water soluble complex consisting of a
core of ferric hydroxide and a protein shell
(apoferritin)
 hemosiderin (a particulate substance consisting of
aggregates of ferric core crystals)
Iron distribution and storage
Initial symptoms
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easy fatigability
lack of appetite
headache
dizziness
palpitations
then: hypochromic-microcytic anemia
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microcytosis (small RBCs)
hypochromia (poor fill of hemoglobin)
poikilocytosis (bizarre shapes)
anisocytosis (variable sizes)
IRON DEFICIENCY
Causes:
◦ excessive blood loss (parasitic, accidental,
menstrual): is most common cause
◦ rapid growth in children with limited intake of
iron
◦ malabsorption
 gastric resection
 sprue
◦ increased metabolic requirement
 pregnancy, lactation or neoplasia
IRON DEFICIENCY
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hematology (microcytic hypochromic cells)
low serum iron
low serum ferritin( indicates low body
stores)
low hemosiderin
high total iron binding capacity (TIBC)
Diagnosis of iron deficiency
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average diet contains 10 - 15 mg of iron
per day
a normal person absorbs 5 -10% of this
iron or 0.5 - 1.0 mg daily
iron absorption increases in response to
low iron stores
menstruating women: 1 - 2 mg per day
pregnant women: 3 - 4 mg per day
Iron absorption
give 200 - 400 mg of iron per day
up to 25% of the iron preparation may be
absorbed
 give on an empty stomach
 enteric coated iron tablet should not be
taken
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Treatment of iron deficiency
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parenteral iron is used in patients who
have had bowel resections or in cases of
inflammatory bowel disease
◦ normally given IM (painful)
oral iron causes black stools, constipation,
cramping
 do not administer with antacids or metal
chelators (tetracyclines)
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Treatment of iron deficiency
common in small children ingesting large
doses of soluble iron compounds
Acute iron toxicity
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Required for carbohydrate
and fat metabolism
Toxcity:
•Food sources: nuts,
shellfish, meat/fish poultry,
Brittle hair and nails
whole grains, meat, milk
Skin rash
•RDA for adults:
55ug/day
Nausea and vomiting
Weakness
Difeciency
Heart disease
Arthritis
Impaired immune function
selenium
Muscle pain and wasting
Depression
Assist more than 100 enzyme systems
Zinc
 Required for proper immune function
 Growth and sexual maturation
 Gene regulation
Deficiency
 Toxicity:
• Growth retardation
 Nausea and vomiting
• Delayed sexual
 Diarrhea
maturation
 Depressed immune function
• Eye and skin lesions
 Headach
• Hair loss
 Decrease absorption of
• Increase incidence of
copper
illness and infection
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•Food sources: meat/fish poultry( best absorbed form
of zinc), fortified cereals and legumes
•RDA for man: 11mg/day
•RDA for woman: 8mg/day