Exam 4 Flashcards
Mineral nutrients
Elements
Present in small quantities
Mineral element rankings
Calcium > phosphorus > potassium > sodium = chloride > magnesium
Major minerals
Calcium
Phosphorus
Magnesium
Sodium
Chloride
Potassium
Trace minerals
Iron
Copper
Iodine
Selenium
Chromium
Manganese
Molybdenum
Zinc
Roles of minerals
Electrolyte
Structure
Component of a prosthetic group
Signal transduction
Cofactor role
Factors affecting mineral content
Genetic variation (animals and plants)
Mineral content of animal feed/medications
Mineral content of soil/water for plants
Cooking utensils
Food processing
Fortification
Bioavailability
Rate and extent to which a nutrient is absorbed and used
Calcium functions
Bone health
Catalytic role
Signal transduction
Calcium bone health
Part of bone structure
Hydroxyapatite in bone
The trabecular bone structure of bone marrow and blood vessel
Osteoblasts
Build new bone
Osteoclasts
Dissolve bone to mobilize calcium
Calcium catalytic role extracellular
Regulation of blood clotting/coagulation
Calcium catalytic role Intracellular
Regulation of muscle contraction
Transmission of nerve impulses
Secretion of hormones
Activation of enzyme reactions
Calcium absorption enhanced by
Active vitamin D hormone
Lactose , other sugars
Adequate protein intake
Increased calcium needs (pregnancy)
Calcium absorption inhibited by
Lack of stomach acid
Vitmain D deficiency
High phosphours intake
Phytate
Oxalate
Calcium sources (50% absorbed)
Cauliflower
Cabbage
Brussel sprouts
Kale
Broccoli
Calcium sources (30% absorbed)
Milk
Yogurt
Fortified foods
Calcium sources <5% absorbed
Spinach (due to oxalate)
Maintain mineral balance
Minerals are not expended/destroyed during biological processes
Required in diets due to variable efficiency in recycling
Bioavailability
Transition metals can be reactive and/or toxic
Parathyroid hormone
Raise blood calcium levels
Stimulates activation of vitamin D
Stimulates calcium reabsorption in kidney, intestine
Stimulates resorption/release from bones
Calcitonin
Lower blood calcium levels
Inhibits activation of vitamin D
Prevents calcium reabsorption in kidney
Limits calcium absorption in intestines
Inhibits resorption from bones
Osteoporosis
Silent diseases
Increases when you age
Osteoporosis prevention
Weight-bearing exercise
Resistance exercise
Nutrition
Weight bearing exercise
Work against gravity
Cycling and swimming does not count
Resistance exercise
Delays the rate of bone density drop
Increase mechanical force that increases osteoblast and decreases osteoclast
Phosphorus
2nd most abundant mineral in the body
Hydroxyapatite in bone and teeth
Phosphorus roles
Part of major buffer system
Part of RNA/DNA
Assist in energy metabolism
Help transport lipids in the blood
Structural component of cell membranes
Magnesium roles
Maintain bone health
Part of protein making machinery
Necessary for energy metabolism
Participates in enzyme systems
Muscle contraction and blood clotting
Supports normal function of immune system
Stabilizes ATP
Iron functions
Oxygen carrier
Cofactor of enzymes
Iron: oxygen carrier
Iron helps accept, carry, release oxygen
Heme has Fe 2+ at center of porphyrin ring
Hemoglobin
4 heme groups, protein subunits
Each subunit can carry an oxygen
Delivers oxygen and moves CO2
Myoglobin
Heme protein in muscle cells
Single heme group and subunit
Release oxygen to cells
Iron cofactor
Enzymes in TCA cycle
Cytochromes in ETC
Production of neurotransmitters
Redox active
Iron gene expression
Packing and unpacking of DNA → transcription → mRNA → translation → protein processing → protein degradation
Fe 2+
Ferrous iron
Fe3+
Ferric iron
Proteins requiring iron to function
Hemoglobin
Myoglobin
Iron containing enzymes
Iron transport proteins
Transferrin
Transferrin receptor
Ferroportin
Iron storage protein
Ferritin
Iron sources
Heme and nonheme
Meat
Poultry
Fish
Tofu
Dried beans
Dark chocolate
Whole grains
Green leafy vegetables
Absorb heme iron
Goes through heme transporter into enterocyte
Absorb nonheme iron
Has to be reduced to Fe 2+
Goes through DMT1 into enterocyte
DMT1 handles other 2+ ions
Iron might have to compete with Zn or Ca
Absorb food iron
Food iron –> mucosal cells
If not needed –> excreted
If needed –> ferritin, transferring, blood, body
Absorbing iron
If iron isn’t needed
Travels to ferritin
Stored
If iron is needed
Goes to ferroportin
Has to be oxidized to Fe 3+ (need Copper)
Attaches to transferrin
Travels throughout the body
Heme transporter
Transport heme iron into enterocyte
DMT1
Divalent metal transporter 1
Transports Fe2+
Ferroportin
Transports Fe2+ out of enterocyte, into liver
Transports cell membrane (opens it up)
Allows cells to send out iron
Transferrin
Moves iron around
Transport ferric iron to body cells
Transferrin receptor
Cells make it
Picks up iron from circulation
Ferroxidase
Oxidizes Fe2+ into Fe3+ so it can attach to transferrin
Ferritin
Iron binding protein
Produced in enterocytes
Binds and stores mucosal iron
Prevents it from entering the bloodstream
Low iron stores
Transport protein production increases
Ferritin production decreases
Allow iron into bloodstream
High iron stores
Transport production decreases
Ferritin production increases
Stored iron is excreted when enterocytes are sloughed
Enhance iron absorption
Increased requirements
Consumption of animal tissues
Fe 2+ is better absorbed than Fe 3+
Heme iron is better absorbed
Vitamin C
Gastric acid
Inhibit iron absorption
Decreased requirements
Phytate in whole grains and legumes
Oxalate in green leafy vegetables
High fiber intake
Polyphenols
Excess Ca, Zn, Mn
Bioavailability factors
Method of food prep
Nutrient nutrient interaction
Nutrition status
Physiological need
Dietary substances
Fiber
Phytate
Oxalate
Polyphenols
Gastric acidity
Genetic variation
Aging
