Minerals Flashcards
General properties of minerals
Inorganic
Retain chemical identity
Not destroyed by heat, air, acid, light
Classified as: macro, micro trace, ultra-trace
Major minerals
Ca, P, Mg, Na, K, Cl, S
Trace Minerals
Fe, Zn, Mn, Cu, I, Se, Cr, F, Mo
Factors that influence mineral absorption
Not all can be absorbed Can compete for absorption sites Presence of vitamins Animal products are better absorbed Presence of binders and dietary fiber
General Functions of Minerals
Energy Metabolism (cofactors) Components of body compounds (RBCs, B12, bones, stomach acid, thyroid hormone) Water balance Transmission of nerve impulses Muscle contraction Growth and development
Risk for mineral deficiencies in the US
prolonged dietary inadequacies
decreased absorption
Calcium, Iron, and Zinc
Mineral Toxicity
Easy to reach UL and beyond especially with trace minerals (Fe, Cu, Zn, Se)
Too much can interfere with one another
Calcium absorption
Requires acidic environment (pH < 6) and depends on active Vit D
What protein binds with calcium?
Calbindin (turned on by Vit D)
What increases calcium absorption?
Acidic conditions in food (ex: OJ fortified with Ca)
Presence of Vit D
Lactose, glucose, Increased need (esp pregnancy)
Certain hormones (estrogen, growth hormone, PTH)
What decreases calcium absorption
Fiber, phytates, oxalates High P intake, excessive Fe, Zn Vit D deficiency Increased GI motility Steatorrhea (unabsorbed fat) Certain medications (thyroxin, cortisones, ANTACIDS) Increased urinary excretion Aging Gender Menopause
Organs and hormones involved in Calcium homeostatis
Thyroid, parathyroid (calcitonin, PTH)
Intestines
Kidneys
Bones
Calcium homeostasis: rising blood Ca
signals the thyroid to secrete calcitonin to inhibit activation of Vit D and prevents Ca reabsorption in the kidneys, limits absorption in the intestines, inhibits osteoclasts from breaking down bone
Calcium homeostasis: Falling blood Ca
signals the parathyroid glands to secrete parathormone: stimulates activation of Vit D. Together hey stimulate calcium reabsorption in the kidneys and enhances Ca absorption in intestines, stimulate osteoclast cells to break down bone to release Ca into blood
Osteoclasts
CUT Ca from bone: release calcium from bone, reabsorbed into blood, bone eroded
Osteoblasts
BUILD Ca into bone: secrete collagen matrix, bone mineral, promote bone formation
Ca Functions
Bone Development and Maintenance Blood clotting Nerve impulse transmission Muscle contraction (Cell Metabolism)
Bone structure: mineralization
Calcium is part of a crystal that is laid down on collagen. The more crystal the stronger the structure of the bone: HYDROXYAPATITE. This is what is released by osteoclasts.
Bone Mass
More bone mass in areas under higher stress
Peak bone mass reached between the age of 20-30
Bone loss begins in mid-adulthood
Significant loss at menopause
How to build higher bone mass
adequate diet healthy body weight normal menses weight bearing PA moderate intakes of protein, P, Na, Caffeine non-smoker lower the use of certain medications
Calcium and Blood clotting
Vit K–> gla proteins–>binds Ca
Prothrombin–> thrombin
Formation of fibrin
Ca and transmission of nerve impulses
Nerve impulse arrives and stimulates Ca influx –>releases neurotransmitters –> carries impulse across synapse to target cell
Muscle Contraction and Ca
Skeletal muscle stimulated by nerve impulse –> Ca ions released from intracellular stores within muscle cells –> ca and ATP allow contractile proteins to slide along each other
Ca deficiency
Osteoporosis
Osteopenia
stunted growth in children
tetany: uncontrolled muscle contraction, muslce plain, spasms, parathesia
Osteoporosis
Bones become porous and fragile (most common in postmenopausal women)
Risk factors for osteoporosis
Older age, low BMI, Race, smoking, excess alcohol consumption, sedentary lifestyle, female, maternal history,inadequate Ca and vit D throughout life,
Hypercalcemia
Ca toxicitiy
Usually due to hyperparathyroidism or malignancy, or due to pharmacological does of calcium
-kidney stones, constipation, soft tissue caclification
Ca AI
1000-1200 mg/day (based on 40% absorption)
Food sources of Ca
milk, dairy products, kale, collard, mustard greens, Ca fortified foods, canned fish
Phosphorus
85% found in skeleton, 14% soft tissue, 1% in blood and body fluids
Phosphorus absorption
enhanced by calcitriol (active Vit D)
Functions of Phosphorus
Mineralization of bones and teeth
Acid-base balance
Component of essential body compounds (structural and regulatory roles, energy storage and transfer)
P containing compounds
ATP, ADP
DNA, RNA
Phospholipids
Bone, Vit coenzymes, phosphorylated enzymes, proteins, and nutrients
P Deficiency
Rare, Hypophosphatemia:can be due to inadequate absorption from GI tract, increased excretion from kidneys
Refeeding syndrome: occurs in malnourished who are aggressively refed; P in blood shifts into cells, leaves blood levels even lower
P Toxicity
Rare: Altered Ca: P ratios: precipitates form, insoluble, insoluble, bone loss, hypocalcemia, tetany
RDA for P
RDA: 700 mg/d
Food Sources of P
widely distributed in foods, meat poultry, fish, eggs, milk, milk products, nuts, legumes, cereals, grains, soft drinks, coffee, tea, food additives
Magnesium
55-60% found in bone
20-25% in soft tissue
1% in plasma
Mg aborption
40-60% absorbed
kidneys regulate Mg concentration in blood
Mg functions
bone structure
associated with ATP, ADP
Nerve impulses and muscle contraction (Ca antagonist)
Magnesium deficiency
Rapid heartbeat, irritability, weakness (may be due impaired Na/K pumping)
Low magnesium tetany (uncontrolled neuromuscular tremors, convulsive seizures)
Low Ca, increased risk of osteoporosis
Mg toxicitiy
excessive intake can lead to diarrhea, can happen with impaired renal function or iv administration
Mg RDA
310 mg/d for women, 400 mg for me
Mg food sources
primarily in leafy grean plants, whole grains, nuts, seeds, hard tap water, dairy meat, chocolate, cocoa
What is an electrolyte?
all mineral salts whose ions dissolve in water (ions dissolved in water carry electrical current
Electrolytes and fluid balance
electrolytes attract water and water follows electrolytes
Osmosis
movement of water across a membrane from a less concentrated to a more concentrated solution
Osmotic pressure
amount of force needed to prevent this movement of water
Cell fluid balance
cells maintain intracellular H2O volume and electrolyte concentrations in narrow range, balance ion concentrations inside and outside of cell
Total positive ions = total negative ions
Electrolyte functions
fluid balance (osmotic pressure)
muscle contraction
transmission of nerve impulses
acid-base balance
Most important electrolytes
Sodium, Potassium, Chloride
Sodium excretion
regulated by kidneys (antidiuretic hormone, aldosterone, renin, angiotensin II) –> has effect on blood pressure
Na Functions
Participates in nutrient absorption/transport Maintains fluid, pH balance Maintains pH balance Muscle contraction Nerve transmission
Na deficiency
Rare (can be due to persistent vomiting/diarrhea or excessive perspiration)
Hyponatremia
Hyponatremia
low blood sodium- irritability, confusion, weakness, hostility, muscle cramps, nausea, vomiting, dizziness, shock, coma
Sodium toxicity
Hypernatremia Increased Ca excretion Kidney stone formation High intake accompanied by lack of water Symptoms: edema, acute hypertension
Na and Hypertension
High Na intake DOES NOT CAUSE hypertension
Na+ can contribute, but NaCl has the greatest effect on BP
Salt Sensitivity
Some people are more sensitive to BP effects
Genetic predisposition, advanced age, African Americans, chronic kidney disease,, hypertension, diabetes, obesity
Sodium AI
1500 mg/day
Food sources of sodium
canned meats, soups, condiments, pickled foods, traditional snacks
Potassium Functions
Maintains fluid and electrolyte balance
Supports cell integrity
Nerve-impulse transmission
Muscle Contraction
Potassium Deficiency
Rare, caused by excessive losses
Hypokalemia
Hypokalemia
muscle weakness, bloating, heart abnormalities
Hyperkalemia
Potassium toxicity- results in severe arrhythmias and cardiac arrest, usually due to impaired renal function, can stop heart if injected into vein
Potassium AI
4700 mg/day
K Food Sources
milk, potatoes, coffee, tomatoes, orange juice
Potassium and Hypertension
High intake is related to low prevalence of hypertension and stroke
DASH diet
dietary approaches to stop hypertension Key Foods: fruits, veggies, low fat dairy, nuts Key Components: High Ca, K, Mg Low in Na Low in fat, sat fat High fiber
Chloride
negative charge neutralizes positive charge of Na and maintains electrolyte balance
Cl functions
major electrolyte formation of gastric acid (HCl) immune response (phagocytosis) nerve function chloride shift
Cl shift
helps transport CO2 from body tissues to lungs, disposal of Co2 in exhaled air
Cl deficiency
does not occur under normal circumstances
severe diarrhea, vomiting –> convulsions
Toxicity
Large intake may cause fluid retention and implicated in blood pressure increase
Cl AI
2.3 g/d
Foods with Cl
mostly consumed via NaCl, but also found in eggs, milk, meat, seafood
Trace Minerals
Daily nutritional needs <100 mg 9 essential (Fe, Zn, Cu, Mn, Se, Cr, I, F, Mo)
Worldwide iron deficiency
most common nutritional deficiency worldwide
affects >1 billion in developing countries
in most developed nations, 2/3 of all children and women of child bearing age
Iron
65% found in hemoglobin (functional)
10% in myoglobin
1-5% is part of enzymes
remainder in blood or storage (nonfunctional)
Iron in body dependent on
gender, age, size, nutritional status, general health stores, Fe stores
Trace Minerals
Daily nutritional needs <100 mg 9 essential (Fe, Zn, Cu, Mn, Se, Cr, I, F, Mo)
Worldwide iron deficiency
most common nutritional deficiency worldwide
affects >1 billion in developing countries
in most developed nations, 2/3 of all children and women of child bearing age
Iron
65% found in hemoglobin (functional)
10% in myoglobin
1-5% is part of enzymes
remainder in blood or storage (nonfunctional)
Iron in body dependent on
gender, age, size, nutritional status, general health stores, Fe stores
Two forms of iron
Heme iron: contained in hemoglobin, myoglobin of meat, fish, poultry (more bioavailable)
Nonheme iron: present in veggies, grains, and supplements
Mucosal Block
Fe in food is absorbed into mucosal cells of small intestine–>get attached to a protein called ferritin binds with Fe and binds it in cell for as long as the cell is alive (3-6 days). If body has need for iron it will get transported to wherever it is needed or into storage. Must be bound to transferrin. If your body does not need iron it will stay bound to ferritin and when cells die off the iron gets excreted with it.
Absorption of heme iron
proteases cleave globin from hemoglobin, myoglobin and heme is absorbed intact in small intestine
Heme oxygenase hydrolyzes Fe fromprotoporyphyrin
Factors enhancing nonheme Fe absorption
meat, fish poultry (MFP factor)
Acids: ascorbic acid, HCl from stomach, citric lactac acids from foods
Sugars
Factors inhibiting Noneheme Fe absorption
Phytates and fibers (whole grains, soy, nuts) Oxalates: spinach, beets, rhubarb Calcium and phosphorus (milk) tannins and polyphenols (tea, coffee) EDTA (food additives) *can cause milk anemia
Mucosal Block
Fe in food is absorbed into mucosal cells of small intestine–>get attached to a protein called ferritin binds with Fe and binds it in cell for as long as the cell is alive (3-6 days). If body has need for iron it will get transported to wherever it is needed or into storage. Must be bound to transferrin. If your body does not need iron it will stay bound to ferritin and when cells die off the iron gets excreted with it.
Functions of Fe
Component of body proteins: Hemoglobin, Myoglogbin, cytochromes
Enzyme cofactor
Fe toxicity
Fe poisoning, accidental Fe overload (usually from supplements)
Who is at risk for Iron deficiency anemia
pregnant women, infants & toddlers, teenagers, women in childbearing years, vegans, runners
Symptoms of Iron Deficiency Anemia
fatigue upon exertion, difficulty concentrating
Iron Deficiency without anemia
Paleness, brittle nails, fatigue, difficulty breathing, poor growth
Pica: behavior associated with deficiency: consuming non food substances
Fe toxicity
Fe poisoning, accidental Fe overload (usually from supplements)
Factors that inhibit Zn absorption
fiber, phytates, oxalates, Fe, Cu
Fe RDA
8 mg/day males
18 mg/day females (under 50)
Food sources of Iron
red meat, poultry, fish, eggs, enriched grains, fortified cereals, legumes, dark green leafy vegetables, dried fruit, iron skillet
Factors that enhance Zinc absorption
protein, citric and picolinic acids from human milk, low Zn status
Factors that inhibit Zn absorption
fiber, phytates, oxalates, Fe, Cu
Zn Absorption and transport
Stored in cell, bound to metallothionein
Transported through cell (CRIP) into plasma bound to albumin for use by other tissues
Zinc Excretion
metallothionein synthesis regulates Zn absorption (can prevent overabsorption); mucosal block similar to Fe
Excretion: Mucosal block and intestines to body and back to intestine
also excreted in urine and sweat
Zn functions
metalloenzyme component: provides structural integrity to enzyme, and/or participates in catalytic reaction, required by more enzymes than all trace minerals combined
Zn foods
animal products, shellfish, legumes, nuts, whole grains (NOT ENRICHED)
Acrodermatitis enteropathica
severe deficiency, rare genetic disease, severe dermatitis in infants, switched from breast milk to cow’s milk
Zinc toxicity
chronic toxicity: imparired Fe, Cu status, anemia, immune deficiency, reduces HDL
Acute toxicity: diarrhea, cramps, nausea, vomiting
Zn RDA
8 mg/day women
11 mg/day men
Zn foods
animal products, shellfish, legumes, nuts, whole grains (NOT ENRICHED)
Functions of Cu
metalloprotein component and enzyme cofactor
Ceruloplasmin: transports Cu in blood, oxidizes Fe2 to Fe3 for transport, key factor in hemoglobin synthesis, helps release stored Fe from ferritin
Ceruloplasmin and Iron transport
ferroxidase activity, High Fe intake interferes
*why prolonged Cu deficiency can cause anemia
Copper deficiency
rare
Genetic defect: Menkes’ kinky hair syndrome
Iron deficiency anemia due to supplementation
Cu toxicity
not common
Acute: hemolytic anemia, liver, kidney damage, vomiting
Chronic (hereditary): Wilson’s disease accumulates copper in the liver, brain, kidneys, and cornea leading to premature death if undetected
Copper RDA
900 micrograms for adults
Food sources of Cu
organ meats, shellfish, nuts, cocoa, mushrooms, whole grains
Selenium (Se)
Occurs in foods as selenocysteine and selenomethionine
Se food sources
Organ meats, seafood, muscle meats, whole grains, dairy, fruits and vegetables
Se deficiency
Keshan disease: viral, heart disease
Se Toxicity
Selenosis: excess supplementation, nausea, vomiting, fatigue, diarrhea, hair and nail loss or brittleness, inhibition of protein synthesis, garlic breath odor
Acute poisoning can be lethal
Se RDA
55 micrograms/day
Se food sources
Organ meats, seafood, muscle meats, whole grains, dairy, fruits and vegetables
Iodide functions
integral part of thyroid hormones: regulate metabolic rate, growth, development, etc.
Iodide deficiency
Insufficient thyroxine; thyroid continually releases TSH and thyroid cell size increases in size and number
Goiter:
enlargement of thyroid gland due to Iodide deficiency
Iodide toxicity
thyroid gland enlargement, thyroid hormone synthesis is inhibited
Iodide RDA
150 micrograms/day
Iodide food sources
iodized salt, saltwater fish, seafood, molasses
Fluoride Functions
Prevents demineralization of calcified tissues
Aids in synthesis of flourapatite crystals
Protects against tooth decay
Increases bone mass
Fl toxicity
flourosis: mottling of teeth
Fluoride AI
- 1 mg/day women
3. 8 mg/day men
Food sources of Fl
tea, seafood (consumed with bones), seaweed, grains, vegetables
Chromium Functions
Enhances insulin action: mechanism of action under investigation
Glucose tolerance factor: may initiate S-S bridging
Chromium Deficiency
impaired glucose tolerance- diabetes like
Chromium toxicity
no toxicity from foods, possible industrial exposure
Chromium AI
35 micrograms/day men
25 micrograms/day women
Chromium food sources
small amount of information available, in plants it is dependent on soil content
Most reliable: meats, poultry, egg yolk, brain, whole grain, cheese, mushrooms
Manganese functions
enzyme cofactor: binds to ATP, ADP, facilitates macronutrient metabolism
Mg AI
1.8-2.3 mg/day
Mg deficiency and toxicity
deficiency is rare, toxicity from supplements, environmental contamination or nervous system disorders
Molybdenum (Mo)
Essential cofactor for xanthine oxidase/dehydrogenase
Deficiency: rare, toxicity only in lab animals
Mo RDA
45 micrograms/day
Mo food sources
milk, milk products, beans, whole grains, nuts
Ultratrace minerals
Boron, Nickel, Silicon, Arsenic, Vanadium
