Micronutrients Flashcards
How are micronutrients categorized?
Water and salts
minerals
vitamins
6 functions of Ca
regulation of intracellular enzymes blood clotting muscle contraction growth of bones and teeth calmodulin binding messenger function; hormone-receptor
Absorption of Ca promoted by:
Vit D Gastric acid lactose citrate, malate protein, phosphorous exercise
Absorption of Ca2+ prohibited by:
Oxalic acid Phytic acid Dietary fiber Phosphate Steatorrhea (soap) [fatty diarrhea]
Metal- phosphates are extremely (soluble/insoluble)
insoluble
What is seen in calcium deficiencies?
Rickets
osteomalacia (adult rickets)
osteoporosis
What prevents rickets?
Vitamin D
What is recommended consumption of Ca2+?
1000mg/day
women and adolescents need slightly more
What form of phosphorous is absorbed?
phosphate
Where is the vast majority of phosphate found?
85% bones and teeth
What is recommended intake of phosporous?
700-1250 mg/day
Excessive intake of phosphorous promotes excretion of what mineral?
Ca2+
What is the function of magnesium?
bone strength ATP hydrolysis enzyme cofactors binds nucleic acids muscle relaxation after contractions
What are the food sources of magnesium?
vegetables, nuts, legumes
What is the RDA of magnesium?
400 mg/day (male) 300 mg/day (female)
What symptoms are seen with deficiency of Mg? excess?
hypertension, vascular disease, preeclampsia
Alcoholics - DTs, tremors
Excess - anaesthetic effects, diarrhea
How is sulfur taken up by the body?
sulfate
What are some functions of sulfur?
source of electrons,
transfer groups Acetyl Coa
disulfide bonds, protein folding
Key metals involved in enzymatic activities and protein structure
Fe, Zn, Selenium, iodine Cu
What is the key role of Iron?
enzyme catalysis
electron transfer
oxygen transport
What is the role of Zinc?
catalysis
structure
protein interacting with DNA “Zinc fingers” (gene regulation)
Is Zinc redox active?
NO!!
What increases absorption of zinc? How is it bound?
binding of His, Cys (in various combinations) and nucleotides
What helps with Zn transfer into blood?
metallothioneins
Where is Zn stored?
muscle & bone
What are the Zn requirements?
M- 11 mg/day W 8mg/day
What are symptoms of Zn deficiency?
skin lesions, late onset of secondary sex characteristics, growth reduction, loss of appetite, genetic deficiiencies
What does Zn malabsorption lead to?
IBD
Too much Zn?
dizziness, nausea, gastric distress
can reduce Cu absorption
implicated in Alzheimer’s
can lower HDLs
What are Cu RDA?
0.9 mg/day
What is Cu used for?
cytochrome oxidase
What other metal relies on Cu for uptake? **
Fe
What impairs Cu uptake?
Excess Zn
What is seen with Cu deficiencies?
anemia, leukopenia, neutropenia, osteoporosis
What will excess Cu result in?
tremors, weakness, anorexia
What disease can impair absorption of nutrients?
Crohn’s, CF
Describe Wilson’s disease?
excess Cu and builds up leading to brain damage, involuntary movements
What is a sign of Wilson’s
gold rings in corneas
What is iodine essential for?
thyroid hormones affecting development, growth, metabolism
What is RDA for iodine?
150 MICROgrams/day
Deficiency of iodine will stimulate what disease?
goiter - enlarged thyroid
What is RDA for selenium?
55 MICROgrams/day
Deficiency of selenium can lead to?
cardiac failure, liver disease, cancer, atherosclerosis, hair loss
An excess of selenium (>400 ug/day) can lead to?
peripheral neuropathy, nausea, diarrhea, dermatitis, hair loss, nail deformities
What is selenium used for?
enzyme cofactor for antioxidant defense
thyroid hormone and insulin function
regulation of cell growth
fertility
What are some other metals needed?
Manganese, molybedium, chromium, cobalt, nickel
Probably required metals?
boron silicon, arsenic, tin, rubidium, germanium
possibly required metals?
Cd (Cadmium) Pb (Lead) Li (lithium) Al (Aluminuam Br (Bromine) Rd, ? Rb - Rubidium V - Vanadium F - Fluorine
What are the major extracellular fluids (ECF) solutes?
Na+
Cl-
HCO3-
What are the major intracellular fluid solutes?
K+
organic phosphate esters (ATP, creatine phosphate, phospholipid)
What are miliequivalents?
milliequivalents = milliMolar when 1 ionizable group
mEQ = 2x mMolar is there are 2 charges
If 3+, more pH dependent
What are the main macrominerals?
sodium
potassium
What does excess sodium lead to?
hypertension
ECF expansion
The net activity of GI tract down to jejunum is secrection of water and electrolytes. If you vomit you?
lose solutes
The net activity from jejunum to colon in reabsorption so if you have diarrheas you can lose?
liters /water
What problems exist with excess or deficiency of water and potassium?
cardiac arrest
K:Na ration linked to hypertension
Deficiency: heart arrhythmia, muscle weakness, increased blood pH (alkalosis)
What are four other macro minerals besides water, Na, K?
Calcium
Phosphorous
Sulfur
Magnesium
What is the function of phophorous
structure of nucleic acids, phospholipids
activation of enzymes by phosphorylation
Energy (ATP)
acid-base balance
