Transcript BIOL103 Ch 8 Minerals Fall16 for Students

Chapter 8
Water & Minerals:
The Ocean Within
A Note to My Students
• Please use these lecture notes in addition to the
previous lecture notes on chapter 8
• The material is the same, but has been
reorganized so that you can better understand
that nutrients work together to serve a similar
purpose/function
• I have added my own thoughts to some of the
slides so that you will not miss the main points
• Email me or have office hours with me if you have
any further questions on the material
Understanding Minerals
• Minerals
– Inorganic
– Not destroyed by heat, light, acidity, alkalinity
– Micronutrients (needed in small amounts)
– Grouped as:
1. Major minerals (>100 mg/day)
2. Trace minerals (<100 mg/day)
Minerals in Foods
• Found in plant (soil) and animal (diet) foods
• Found in drinking water: sodium, magnesium,
fluoride
• Mineral absorption limited by several factors:
1. GI tract length
2. Competing minerals (ex. megadose)
3. High-fiber diet contain phytates (iron, zinc,
manganese, calcium)
4. Oxalate (calcium)
Major Minerals and Health
• Mineral status significantly affects health
• Play critical parts in hypertension and
osteoporosis
Hypertension
• Fluid balance (blood, sweat, tears)
– Sodium, Potassium, and Chloride
– In our kidney: maintain balance of electrolytes
to pull water across a wall of cells from the
bloodstream  bladder
• Hypertension: high blood pressure
– Diet:
• High sodium, low potassium
• More salt  less water removed = higher BP
Nerve Impulse Balance
• Neurons send messages electrical signals
using charged chemicals
– Sodium (Na+): outside
– Chloride (Cl-) : outside
– Potassium (K+): inside
– Calcium (Ca2+): out, at end of axon
Steps:
1. At rest: Na+ is outside,
K+ is inside
• Overall, electrical
charge is negative
inside than outside
2. Stimulus opens Na+ ion
gates: Na+ in
3. Action Potential is
created  signal is
transmitted
Nerve Impulse Balance
• Transmission of a nerve
impulse is rapid and
self-propagating (like
dominoes)
• Transmission of nerve
impulses depends upon
a difference in charge
across the cell
membrane
Muscle Contraction and Heart Activity
Bone Structure
• Hydroxyapatite: a
crystalline mineral
compound of calcium and
phosphorous
– Supplies Ca and P blood
and soft tissues
• Bone cells
– Osteoblasts
– Osteoclasts
• Fluoride promotes the
deposition of Ca and P in
bones and teeth
Blood Calcium
• Regulation of blood calcium levels
– Calcitriol/Vitamin D
– Parathyroid hormone
– Calcitonin
• Why control blood calcium?
– Important for muscle contraction and nerve
impulses
• If too high  non-responsive
• If too low  spasms, convulsions
Regulation of Blood Calcium and
Vitamin D/Calcitriol
Regulation of Blood Calcium
(Calcitonin and Parathyroid Hormone)
Magnesium
• Function
– Participates in more
than 300 types of
enzyme-driven
reactions such as
energy metabolism
– Cardiac and nerve
function
• Main Storage: Bones
Protein Shape
• Sulfur helps proteins
maintain their
functional shapes such
as skin, hair, nails
– Disulfide Bridges
Trace Minerals
• Trace Minerals:
– Iron, Zinc, Selenium, Iodine, Copper, Manganese,
Fluoride, Chromium, Molybdenum
•
•
•
•
Cofactors for enzymes
Components of hormones
Participate in many chemical reaction
Essential for:
– Growth
– Immune System
Brain and Nervous System
• Nerve cell protection
– Iron helps produce myelin sheath
• Nerve cell communication:
– Iron helps produce neurotransmitters
Oxygen Transport
• Hemoglobin vs. Myoglobin
– Both require iron to help stabilize its
structures
Iron
• Deficiency:
– Iron-deficiency anemia
• Toxicity:
– Adult doses can cause poisoning in children
– Hereditary hemochromatosis – a genetic disorder
in which excessive absorption of iron results in
abnormal iron deposits in the liver and other
tissues.
Detoxification
Molybdenum
– Enzyme cofactor for sulfite
oxidase: sulfite  sulfate
– Sulfur is critical in our
ability (cytochrome P450)
to detoxify unwanted
contaminant in our liver,
and to detoxify heavy
metals
Antioxidant
• Superoxide dimutase (SOD):
1. Cu-Zn SOD
2. Mn-SOD
– Selenium is part of Glutathione Peroxidase:
antioxidant enzyme
•
Glutathione made from Sulfur
• Molybdenum: Sulfite  Sulfate
Thyroids
• Thyroid hormone helps
regulate body
temperature, basal
metabolic rate,
reproduction, and
growth
– Iodine: thyroid hormone
production (T3, T4)
– Selenium: converts
thyroid hormone to its
most active form (T3)
Iodine and Thyroid Gland
Goiter (Iodine Deficiency or Toxicity)
Cretinism (Iodine Deficiency during
Pregnancy)
• Severely stunted physical
and mental growth due to
deficiency of thyroid
hormones, usually due to
maternal hypothyroidism
• Other signs: thickened
skin, enlarged tongue, or
protruding abdomen.
Fluoride
• Functions
– Promotes the deposition of calcium and
phosphate in bones and teeth
• Food sources
– Fluoridated water
• Balance
– Excess can cause fluorosis: discoloration and
“specks” on teeth; weakens teeth.
• The fluoridation debate
Fluorosis
•
•
Fluoridated water responsible for about 40% of fluorosis
Fluoridated toothpaste responsible for about 60% of fluorosis
Absorption vs. Inhibition
• Enhances Absorption:
– Vitamin C and Iron
– Vitamins A, C, E and Selenium
• Inhibition/Competition:
– Copper, Iron, Zinc, (& Calcium)
– Magnesium, Manganese, Calcium (& Iron)
– Copper and Molybdenum
– Oxalate: Calcium (and non-heme iron)
– Phytates: All the minerals
Relationships
• Need vitamins B1, B6, and iron to convert Tryptophan to
B3
• Copper & Iron
– Works with ceruloplasmin, a copper-dependent enzyme
required for iron transport.
• Copper & Zinc
– Wilson’s disease (genetic disorder that increases copper
absorption)
• Selenium & Iodine
– Goiters: Iodine deficiency can be caused by selenium
deficiency
Other Trace Minerals and
Ultratrace Minerals
•
•
•
•
•
Arsenic
Boron
Nickel
Silicon
Vanadium