MCP Lecture 6 Flashcards
Folate: number, function, deficiency, susceptible groups
B9
function: precursor of THF (coenzyme used in generating; precursors for DNA and protein synthesis)
deficiency: neural tube defect, macrocytic anemia, hyperhomocysteinemia
susceptible: pregnant women, elderly, alcoholics
What does folate deficiency cause?
deficiency inhibits DNA synthesis by decreasing availability of purines and dTMP
Cobalamin: number, function, deficiency, susceptible groups
B12
function: coenzyme in methionine synthesis and conversion of methmymalonyl CoA to succinyl CoA
deficiency: pernicious anemia - megaloblastic anemia with demyelination
susceptible: elderly, malabsorption diseases, vegetarians
What makes B12 different than other water-soluble vitamins?
stored very effectively in the liver
What causes deficiency in B12?
lack of intrinsic factor in the stomach
How does intrinsic factor help with absorption of B12?
B12 is released from protein in acidic stomach, binds intrinsic factor, absorbed in distal ileum
How does B12 deficiency affect folate?
folate trapped in form that cannot be used for purine and dTMP synthesis
What causes megaloblastic anemia?
folate and B12 = megaloblastic anemia - deficiency in nucleotides leads to decrease in DNA and RNA synthesis - cells increase in size without dividing - large immature RBCs released and cannot carry sufficient oxygen
What are the macrominerals?
potassium K+ sodium NA+ Chloride Cl- Calcium Ca2+ Phosphorus P Sulfur S Magnesium Mg2+
What are the microminerals?
iron copper zinc chromium iodine manganese selenium molybdenum fluoride boron
What are potassium, sodium, and chloride critical for?
as electrolytes for fluid homeostasis and in neuromuscular function
Calcium: functions, deficiency, susceptible groups
functions: component of bone, signaling, coagulation, muscle contraction, neurotransmission
deficiency: muscle cramps, osteoporosis, rickets
susceptible: children, adult women, elderly
What is required for calcium absorption and utilization?
vitamin D
What is the most abundant mineral in the body?
calcium
What is osteoporosis?
calcium deficiency causing porous bones
Magnesium: functions, deficiency, susceptible groups
functions: essential for many enzymes using MgATP (transporters need Mg to recognize ATP), high levels in bone (required for bone formation)
deficiency: weakness, tremors, cardiac arrhythmia (neuromuscular)
susceptible: alcoholics, patients taking diuretics
Phosphorus: functions, deficiency, susceptible groups
functions: component of bone, nucleic acids, membrane lipids, required in all energy-producing reactions
deficiency: RARE - rickets, muscle weakness and breakdown, seizure
Iron: functions, deficiency, susceptible groups
functions: O2/CO2 transport in hemoglobin, oxidative phosphorylation, cofactor in several nonheme iron proteins and cytochromes
deficiency: microcytic hypochromic anemia, decreased immunity
susceptible: COMMON - children and menstruating women, pregnant, elderly
What causes reduction of Fe3+ to Fe2+?
vitamin C
low pH in stomach helps release Fe3+ from ligands and makes it bioavailable
What are the two major barriers in iron absorption?
- release of Fe3+ from food (iron in spinach is tightly chelated and cannot be absorbed)
- availability of reducing agent to convert Fe3+ to Fe2+
What are characteristics of iron-deficient anemia?
microcytic anemia - small, pale RBCs
-less hg produced - RBCs undergo more cell divisions in bone marrow waiting for synthesis
What are the symptoms of iron-deficient anemia?
fatigue, pallor, weakness, dizziness
What does long term iron toxicity cause?
hemochromatosis - iron overload leading to iron deposits “iron tan” - eventually compromises mitochondrial function leading to lactic acidosis
What does acute iron toxicity cause?
overdose in children - most common cause of death due to toxicity (consumption of adult iron supplements)
What makes metal microminerals a toxic risk?
chemical properties as redox agents that can cause production of ROS
Copper: functions, deficiency, susceptible groups
function: assists iron absorption, cofactor for enzymes required in collagen syntehsis, fatty acid metabolism, and elimination of ROS
deficiency: rare - anemia, hypercholesterolemia, fragility of large arteries (bc collagen synthesis), bone demineralization demyelination
susceptible: Menkes’ syndrome or consuming excessive zinc
What is Menkes’ disease?
copper-deficiency disorder that comes from inherited mutations in a Cu-transporting ATPase - need to transport into golgi to supply Cu to enzymes (enzymes are secreted without Cu without transporter)
What is Wilson’s disease?
mutation resulting in copper overload
copper accumulates in liver with severe liver and nervous symptoms
Zinc: functions, deficiency, susceptible groups
functions: cofactor for many enzymes and plays a structural role in many proteins (zinc finger)
deficiency: poor wound healing, dermatitis, reduced taste acuity, poor growth and impaired sexual development in children
susceptible: alcoholics, elderly, people with malabsorption
What is the earliest symptom of zinc deficiency?
scaly dermatitis
Chromium: functions, deficiency, susceptible groups
function: component of chromodulin - facilitates insulin binding to its receptor
deficiency: impaired glucose tolerance
susceptible: those with impaired glucose tolerance
Iodine: functions, deficiency, source
function: incorporated into triiodothyronine (T3) and thyroxine (T4) - regulates BMR
deficiency: goiter, hyperthyroidism/hypothyroidism
source: saltwater fish
Selenium: functions, deficiency, source
function: component of antioxidant enzymes and deiodinase enzymes
deficiency: Keshan disease - cardiomyopathy and cretinism
source: selenium content in soil
Fluoride
incorporated into bone and teeth - strengthens
Boron
involved in bone formation
sulfur
component of amino acids
Most common vitamin and nutrient deficiencies in children
iron and calcium
Most common vitamin and nutrient deficiencies in teenagers
calcium and magnesium, vitamin A, C, B6
Most common vitamin and nutrient deficiencies in women
iron, calcium, magnesium, B6, folate, D
Most common vitamin and nutrient deficiencies in elderly
B6, B12, D, zinc and chromium
due to compromised absorption
Most common vitamin and nutrient deficiencies in alcoholics
especially folate, B6, thiamine
