Transcript dvsklgfs

12.1 Minerals
Chapter 19
Problem Sets #5 and 6 (Vitamins and
Minerals)
Chapt 19# 1,2, 5,10,11,17,46
MINERALS: Macro- and MicroNutritional minerals: the various elements
that are essential for proper functioning of
the human metabolism, ie. for good health.
Living beings simply cannot generate minerals in
their own bodies.
All of our minerals became part of the earth at its
creation and enter our bodies only from the earth,
directly through the plants we eat or indirectly
from the animals that feed on plants.
Fats
20%
20%
Protein,
Carbohydrates,
Calcium, Phosphorus
Water
60%
Vitamins and all
other minerals
(less than 1%)
Of the nearly 90 naturally-occurring elements,
only 11 of them make up over 99% of the
mass of the human body.
Major Elements of the Human Body
Element
Oxygen
Carbon
Hydrogen
Nitrogen
Calcium
Phosphorus
Chlorine
Potassium
Sulfur
Sodium
Magnesium
Symbol
% by weight
% by atoms
O
C
H
N
Ca
P
Cl
K
S
Na
Mg
64.6
18.0
10.0
3.1
1.9
1.1
0.40
0.36
0.25
0.11
0.03
25.5
9.4
63.0
1.4
0.3
0.2
0.06
0.03
0.05
0.04
0.01
Elements:
H ,C ,N ,O, (S)
(from macronutrients)
Macro Minerals: Ca, P, Mg, Na, K, Cl, (S)
(over ~400 mg)
Trace Minerals:
(under 15 mg)
F, I, Fe, Cu, Zn, Cr, Mo,
Mn, Co, Se
Probable Trace:
animals )
Ni, Si, Sn, V, B, As
(in
For the essential nutritional minerals of our diet:
the 'metals' are present as cations, eg. Na+,Ca++
the 'non-metals' occur as anions, eg. I-, PO43As a consequence they are water-soluble, are
excreted and may need to be replaced.
Overcooking foods in boiling water will leach out
many of the minerals.
Many mineral supplements are not as readily
absorbable as "natural sources'.
Concentrations of many trace minerals are
dependant on others, ie. ratios are important.
The nutrient minerals have varied functions:
components of enzymes, structural components in
bones and teeth, electrolyte balance in body fluids
and as transport 'vehicles'.
The minerals must be maintained in balanced
amounts, with no deficiencies and no excesses.
Many of the body’s minerals, because they are
water-soluble, are excreted daily in the feces,
urine and sweat and must therefore be
replenished. For most of the minerals, the
amount excreted each day is very nearly the
amount ingested.
There are 46 different minerals in the human
body, 21 of which are known to be essential.
The seven macrominerals make up about 4%
of body weight. They are calcium, phosphorus,
magnesium, sodium, potassium, chloride and
sulfur.
The macrominerals are necessary in building
bones, maintaining body fluids, maintaining proper
pH in body tissues, transmitting nerve impulses,
maintaining cell membrane structures and
facilitating enzyme action.
Sodium , potassium and chloride, as ions
(Na+,K+, Cl- ), are essential to electrolyte balance in
body fluids. Electrolyte balance, in turn, is essential
for fluid balance, acid–base balance and
transmission of nerve impulses.
When there is extreme fluid loss through vomiting,
diarrhea traumatic injury, electrolytes must be
supplied to restore their concentration in body fluids .
Name
Function
Sodium (Na+)
Major extracellular ion
Potassium (K+)
Major intracellular ion
Sodium is a vital micronutrient, but is present in most NA diets
through excessive intake of salt (sodium chloride). Physicians
recommend ingesting about 1.2 grams of sodium/day (or ~ 3gms of
salt). This is twice the estimated minimum requirement.
Many N.Americans exceed the recommended daily intake
by 3X. For example, a typical “double burger” contains nearly
1g of sodium.
Normal daily urinary excretion of sodium is in the range of
1.4 to 7.8g for adults. If excess sodium is not eliminated, water is
retained, which may lead to edema (swollen legs and ankles).
Various clinical studies have shown that increased levels of
sodium raise the blood pressure of some individuals but have no
effect on the blood pressure of others. The high salt diets of 70 g
per day in certain areas of Japan have traditionally produced an
unusually high frequency of heart attacks .
Food limerick #1
There was an old fellow called Walt
Who seasoned his food with much salt
His blood pressure rose
From his head to his toes
So his doctor told him to halt!
Potassium
Though less abundant in the body than its sister
element, sodium, is still essential to intra–cellular
enzyme activity and the transmission of nerve
impulses.
Peaches, watermelon, bananas and potatoes are
rich sources of potassium and can be eaten to meet
the estimated 2g (2000 mg ) daily requirement.
The regulation of the concentration of K+
relative to Na+ is especially important for the proper
rhythmic beating of the heart.
In the case of some nutrient elements, good
health depends on the element being present in
the proper amount and in the proper ratio to one
or more other elements.
An example of an important ratio is the potassium/
sodium ratio (K/Na ratio) which has to be within
certain limits to facilitate the transmission of electrical
signals between nerve cells .
Typical values of the K/Na ratio are greater than 1.
Some K/Na ratios for specific tissues are: muscle,
4; liver, 2.5; heart,1.8; brain,1.7 and kidney,1.0.
Natural, unprocessed food have high K/Na weight
ratios. Fresh, leafy, vegetables average a K/Na
ratio of 35. Fresh, non-leafy vegetable and fruits
average a ratio of 360, with extreme values of 3 for
beets and 840 for bananas. K/Na ratios in meats
range from 2 to 12.
Potassium and sodium compounds are
quite soluble in water. During processing (and
cooking, if foods are boiled), both potassium and
sodium compounds are dissolved by water and
discarded.
The sodium is replenished by “salting” of the food
(addition of sodium chloride). Potassium is
usually not added to the food.
In general
• No nutritional need for us to add salt to our
foods
• Already enough present!!
Calcium
• the major component of bones and teeth
• needed for blood clotting,
• required for muscle contraction and
transmission of other nerve impulses.
• slows down the heartbeat by increasing
electrical resistance across nerve membranes.
Calcium is metabolized in the body by a hormone
synthesized from (vitamin D). Fat slows down
calcium absorption but lactose speeds it up.
Bones and Teeth
If mineralization and demineralization occur at the
same rate, there is a state of dynamic equilibrium
between these two opposing reactions and no net
loss results:
Demineralization
5Ca2+ + 3PO43- + OH-
Ca5(PO4)3OH
Mineralization
NB:
-OH
+ H+
H 2O
Excess H+ removes -OH causing demineralization
Substituting F for OH produces a more stable
crystal and 100 times less soluble in acids.
Hydroxyapatite fluoride effects
• Structural reinforcement
Fluoridation of Drinking water
• NaF at 1 ppm level used since 1960 in most
Canadian cities: substantial reduction in
tooth decay
• Also Sodium monofluorophosphate in
toothpaste Na2PO3F: source of F• Do we need both?
• Argument against “ Fluoride is toxic”
Cheaper fluoride sources
• Hydrofluorosilicic acid (HFSA) now used
extensively (cheaper than NaF)
• By product of wet scrubbing of phosphate
fertilizer factory smokestacks
• CaF2.93Ca3(PO4)2: Fluoroapatite mineral source
• H2SiF6 is shipped as a 23% solution, then diluted
180,000 : 1 with municipal water
• Contains very low levels of lead and arsenic
impurities
Gatineau City council decision
• In favour of fluoridation
• Niagara Regional Council: rejected motion
to fluoridate on Jan 24, 2008
• Still controversial! Ottawa Citizen Letters to
Editor Feb 4, 2008!
• What do you think?
Osteoporosis
A deficiency of calcium, usually in older persons
and especially in post-menopausal women, can
lead to loss of 'bone density' or brittle bones. The
hormone estrogen suppresses bone dissolution.
To maintain good bone density, one should ingest
1) ~1.5g/day of 'soluble' Ca2+; 2) adequate Vit.D
3) adequate Mg2+
This must be accompanied by sufficient weight
bearing exercise.
NB. Caffeine in 5-6 cups of coffee/day inhibits Ca
uptake by 30%!
Bone Density Profiles
D
e +
n
yrs
s
10
20
30
40
50
60
i _
t
general pop’n, pre 1980
y
post menopause, pre 1980
general, 2000!
In women over 65/70 more deaths due to'complications'
of broken hips/pelvis/vertebrae than from breast cancer!
NB. Increasing number of women not reaching
adequate bone density by 30/35 years.
Why the change over the last 27
years?
• Lifestyles becoming more sedentary
• Poorer nutrition
• Too much caffeine?
Hormone Replacement therapy
(HRT)
• Menopausal women given Estrogen
supplements- (recall: estrogen inhibits bone
dissolution)
• Also helps control “hot flashes”
• Downside: increases breast cancer risk
• risk/benefit ratio needs to be considered!
Bone Structure
osteo
normal
Magnesium (Mg++)
Uses: 'energy production'; nerve function; bone &
teeth formation; helps regulate heart rhythm;
assists blood clotting;aids in insulin function.
RNI (Recommended Nutritional Intake):
~200mg/day
Deficiency: risk of heart disease and diabetes
Sources: whole grains, nuts, legumes, green
veggies, shellfish( largely eliminated in
processed foods)
Demo: Magnesium in chlorophyll (peas)
Chorophyll
The “antenna” that plants use to
harvest sun’s energy
-Absorbs both red and violet
light:hence reflected light appears
green
Complementary colors absorbed:
reflected (seen)
Cooking green vegetables (peas)
Central magnesium ion (Mg+2) in
chlorophyll is replaced by 2 protons (H+)
from citric and malic acids in the food. This
changes the amount of E needed to excite
the electrons, hence changing the colour:
yukky green peas!!
Effect of baking soda (NaHCO3)
• Neutralizes the acids in the vegetables
• Green colour maintained (more appetizing)
A penny for your pots!
• Green chlorophyll colour does not fade
when a penny is added to the pot
• Acids in the peas cause a bit of the Cu to
dissolve and the Cu+2 ion displaces the
Mg+2 in the chlorophyll, producing a more
stable complex with a central copper ion.
Keeping pickles looking fresh
and green
• Grandma may have added a penny to the
pickle jar! Vinegar will discolour vegetables
over time.
• “Canning lime” or “pickling lime”:
hydrated CaO used to keep pickles crisper
(less mushy). Ca+2 ion displaces Mg+2.
Phosphorus (PO43-)
Uses: necessary component of bones/teeth,
phospholipids and Adenosine TriPhosphate
(metabolic energy-transfer agent)
RNI: 1000mg(1g)/day
Deficiency: rare
Sources: meat/fish/poultry, dairy products, colas
Sulfur (-SH, SO42-)
Uses: component of two amino acids and
vitamins;
important functional group in 10 protein
structure; part of sulfate anion
RNI: not established
Deficiency: unknown
Sources: all protein (plant & animal): from amino
acids cystine and methionine
Essential Trace Minerals
Ten are confirmed as essential for humans:
iron, copper, zinc, manganese, iodine, fluoride,
chromium, selenium, molybdenum, cobalt,
Essential for mammals, but not yet confirmed for
humans, are:
nickel, vanadium, silicon
(plus arsenic, boron, tin)
Manganese in blueberry juice
• Sharper MRI (magnetic resonance imaging)
signals seen for bile ducts and other parts of
GI system
• Mn atomic number 25 (electron
configuration: 1s2, 2s2,2p6,3s2,3p6,4s2,3d5
has 5 unpaired electrons, hence acts as a
relaxation agent for water and faster MRI
signals
Blueberry juice :rich in
manganese
• Given to patients at St. Paul’s Hospital
Vancouver before MRI scans on GI system.
Micronutrient Terminology in Canada
RNI (Recommended Nutrient Intakes) - the recommended amount of essential nutrients for
healthy individuals in each age/gender group.
RDI (Recommended Daily Intakes) - the highest
recommended RNI value for each nutrient
(used on food labels).
Micronutrient Terminology in USA
RDA (Recommended Dietary Allowances) intake levels of essential nutrients that are
'adequate to meet the known nutritional
needs of practically all healthy persons'.
USRDA (Recommended Daily Allowances) standards for nutritional information on food
labels (based on RDAs).
Similar to, respectively, RNI and RDI in Canada
Nutritional Values - NA 'Harmonization'
Canadian & US nutritional scientists are establishing
consistent values for all food-related categories.
These will be called Dietary Reference Intakes
(DRIs) and will cover the following categories:
1) calcium, vit.D, phosphorus, magnesium, fluoride;
2) folate and other B vitamins; 3) antioxidants;
4) macronutrients; 5) trace elements; 6) electrolytes
and water; 7) fiber and other food components
Compendia for the first two categories are now
(2001) published.
Iodine (I-)
Uses: essential for thyroid gland to produce
thyroxine, a hormone that regulates all cell
metabolism, ie. growth/development.
RNI: 160 mcg/day
Deficiencies: enlarged thyroid(goiter); severe
mental retardation(cretinism) of newborns
can occur if pregnant women are deficient.
Sources: salt water fish/vegetation, iodized salt
Goiter – it’s not pleasant !
Thyroid gland enlargement
• Expands in an attempt to produce enough
thyroxine!
Iodine deficiency was virtually eliminated in NA in
1924 by a Public Health initiative requiring the
inclusion of potassium iodide(KI) in table salt by
the Morton Salt Co.
Worldwide ~1.6 billion people still suffer from
iodine deficiency.
In the 1990's an epidemic of fetal brain
development/mental retardation was reported
from the interior of China leaving ~1 million with
some retardation(>100,000 as cretins)!
Iodized salt
• Mostly NaCl, but KI added
Also present in salt
• SiO2 (sand!) as a very fine powder
• Stops caking by absorbing moisture
• Not metabolized!
Thyroxine – the Thyroid Hormone
HO
CH
Tyrosine(essential a.a.)
COOH
NH2
I2
I
HO
I
O
CH2 CH
NH2
I
I
Thyroxine
COOH
Iron (Fe++)
Iron is part of heme which is critical for the transport
of oxygen by hemoglobin and the temporary storage
of oxygen in heart muscles by myoglobin.
RNI: 8 - 10mg/day (higher for pregnant women)
Deficiency: anemia( the red blood cells are low in
hemoglobin and thus carry a decreased
oxygen supply), fatigue, decreased
resistance to infection.
Sources: animal protein,seafood, dried fruits, bran
Heme Iron in red meat is best!
• Anemia can be caused not only by iron deficiency
but also 'heredity' or lack of vits. B6, B9 or B12
(pernicious anemia).
•A person with 20% of normal hemoglobin levels
still has the energy/strength to walk.
•Iron must be absorbed as Fe2+ ions. Iron from
animal sources tends to be better absorbed
than that ingested from plant sources or 'pills'.
•Caution, excess iron can be toxic!
•An estimated 20% of North Americans (particularly
post-puberty women) have iron deficiencies.
Iron in your cereal (DEMO)
•
•
•
•
Reduced iron : is metallic iron Fe0.
GER ( Gain of electrons is reduction)
Fe+3 (ferric) + 3 electrons > Iron
Fe+2 (ferrous) + 2 electrons > Iron
• Body uses ferrous in heme proteins
myoglobin and hemoglobin
Zinc (Zn++)
Uses: cell growth; proper functioning of
immune system
RNI: 9-12 mg/day
Deficiency: poor wound healing; dwarfism (in
extreme cases, eg. Middle East).
Sources: protein; available in cheese, beans,
nuts, wheat germ but not readily absorbed
Do Zinc supplements treat the
common cold?
• “Zinc is required for the development and
activation of T-lymphocytes, a type of white
blood cell that helps to fight infection. Zn
supplements increase the numbers of Tlymphocytes in the blood and thus help
fight infection”
In general
• It is believed that for Zn lozenges to work, (a) they
must be taken at the first signs of a cold, and (b)
continued for the duration of the cold.
• Most evidence supports (a) but not necessarily (b).
• If (a) works , then (b) should not be needed!!
• Often combined with Vit. C, sugar and Echinacea
in formulation
Zinc lozenges
• Over the counter: take at the 1st sign of a
cold
• Boost immune system
Copper (Cu++)
Uses: structural proteins, nerve cells, pigmentation
Est. ~2mg/day
Deficiencies: poor tendons/ arterial walls, skeletal
defects
Sources: nuts, raisins, liver, legumes, shellfish
Selenium (Se+++)
Uses: antioxidant (anti-cancer?!); reduces blood
thickening
Est. 100mcg/day (extremely toxic if >800mcg)
Sources:
animal protein; grains if soil has it.
Epidemiological / Statistical correlation:
live stock (Great Plains ) and heart disease
(Trendy!) .
Cobalt (Co++)
Uses:
essential part of Vit. B12
RNI: Not established (probably mcg)
Deficiences: anemia, growth retardation
Sources: only animal protein
Chromium (Cr+++)
Use: assists insulin production; helps breakdown
protein and fat
Est. ~150mcg/day
Deficiency: increased risk of diabetes
Source: whole grains, nuts, seafood, prunes,
potatoes