1
Q
folate
A
- B9
- precursor of THF, co-enzyme involved in generating precursors for DNA and protein synthesis
- def: neural tube defects in newborns of deficient mothers
- macrocytic anemia
- hyperhomocysteinemia
-pregnant women, elderly, alcoholics, patients with long term drug treatments, genetic polymorphisms in folate metabolism (relatively common)
2
Q
folate supplementation
A
- deficiency leads to lack of nucleotide synthesis-purines and dTMP
- anticonvulsants and OC pills can interfere with absorption
- inadequate folate early in pregnancy appears to be associated with neural tube defects
- mothers can be deficient without symptoms
- demand very high throughout pregnancy and lactation
- grain products enriched in folate have lowered the risk of deficiency, but supplements still routinely recommended for women of child-bearing age
3
Q
cobalamin
A
- B12
- coenzyme in methionine synthesis and conversion of methylmalonyl CoA to succinyl CoA
- needed in folate metabolism
- pernicious anemia with demyelination
- elderly, patients with malabsorption diseases, long term vegetarians
- from beef, fish, dairy, fortified cereals
- stored effectively even though water soluble
4
Q
B12 and cobalt
A
- contains cobalt chelated in middle of molecule
- B12 in food must be released from protein by acid hydrolysis in the stomach
- then must bind to intrinsic factor to be absorbed in the ileum
- lack of intrinsic factor is a source of B12 deficiency
5
Q
B12 and folate
A
- without B12, folate becomes trapped in a form that can’t be used for purine and dTMP synthesis
- excess folate can bypass trap, but can’t make up for other places B12 is needed
6
Q
folate and B12 deficiencies
A
- result in megaloblastic anemias
- large size of RBCs
- arises from deficiency in nucleotides, leading to decreased RNA and DNA synthesis
- cells increase in size and don’t divide
- can’t carry sufficient oxygen
- pernicious anemia specifically to B12 deficient anemia, resulting from lack of intrinsic factor
7
Q
minerals
A
- inorganic compounds critical for human physiology
- many minerals are enzyme cofactors, but they can also play structural roles in proteins or on their own
- categorized as macrominerals and microminerals based on the level required, but amt doesn’t correlate with importance
- often work in parallel with vitamins, so supplements often have both
8
Q
macrominerals
A
- 100-200 mg/day
- potassium
- sodium
- chloride
- calcium
- phosphorous
- sulfur
- magnesium
9
Q
microminerals
A
- microgram measurements
- iron
- copper
- zinc
- chromium
- iodine
- manganese
- selenium
- molybedenum
- fluoride
- boron
10
Q
calcium
A
- most abundant, from dairy products, leafy green veggies
- major component of bone
- signaling
- coagulation (localization)
- muscle contraction
- neurotransmission
11
Q
calcium deficiency
A
- muscle cramps
- osteoporosis
- rickets
- children, adult women, elderly
- also need vitamin D for absorption
12
Q
calcium and diet
A
- calcium comes solely from diet
- distribution is highly regulated
- 98% in bone and teeth
- hydroxyapatite is basic mineral component Ca5(PO4)3OH
- bone releases Ca if plasma too low
- 2% in rest of body
- low serum calcium signals enhance intestinal absorption and stimulates bone resorption
13
Q
osteoporosis
A
- porous bone from calcium deficiency
- calcium intake during period when bone is reaching maximum density (10-35) is important to prevent osteoporosis-often too late
- even higher levels are required to maintain bone mass in post-menopausal women
- exercise helps maintain density
14
Q
magnesium
A
- essential for many enzymes using MgATP (ATPases) as substrate
- present at high levels in bone
- deficiency leads to weakness, tremors, cardiac arrhythmia
- alcoholics, patients taking diuretics or with severe diarrhea/vomiting
- required for bone formation and 60% Mg in bone
15
Q
phosphorous
A
- mostly present in phosphates
- major component of bone
- constituent of nucleic acids, membrane lipids
- required in all energy producing reactions
- deficiency is rare and can result in rickets, muscle weakness and breakdown, seizure
- quite abundant in food supply
16
Q
iron
A
- o2/co2 transport in hemoglobin
- oxidative phosphorylation
- cofactor in several non-heme iron proteins and cytochromes (redox)
- from meat, dried legumes and fruits, iron enriched cereal products
17
Q
iron deficiency
A
- microcytic, hypochromic anemia
- decreased immunity (myeloperoxidase in macrophages)
- children and menstruating women, pregnant women, elderly
- one of the most common deficiencies worldwide
18
Q
iron absorption and distribution
A
- tightly regulated
- reduction of 3+ to 2+ is promoted by Vitamin C in diet (can get anemia from vitamin C deficiency)
- low pH in stomach helps release 3+ from ligands and makes it bioavailable
- uptake of iron in mucosal cells of small intestine is regulated in response to iron deficient or overload states
- iron is carefully escorted in both circulation and in cells because of potential for inadvertent redox damage
19
Q
barriers to iron absorption
A
- release of 3+ from food and
- availability of reducing agent to convert 3+ to 2+
- spinach has iron tightly chelated
- second requirement often produced by vitamin C
20
Q
characteristics of iron deficient anemia
A
- microcytic
- small, pale RBCs
- less hemoglobin is produced, RBCs undergo more cell divisions in bone marrow waiting for hemoglobin synthesis
- fatigue, pallor, weakness, dizziness
- MCV-measure of average RBC size, dividing line for big or small
21
Q
long term iron toxicity
A
- hemochromatosis
- iron overload leads to iron deposits in multiple tissues
- leads to compromised liver, pancreatic and cardiac function
- ultimately can compromise mitochondrial function and lead to lactic acidosis
- can also come from sickle cell breakdown of RBCs, genetic causes
- ROS
- transition metals can substitute for one another and cause enzymes to not work as well
22
Q
acute iron toxicity
A
- iron overdose in children
- most common cause of death due to toxicity in children under 6
- comes from consumption of adult iron supplements
- ROS
23
Q
copper
A
- assists iron absorption through ceruloplasmin
- cofactor for enzymes required in collagen synthesis, FA metabolism, elimination of ROS
24
Q
copper deficiency
A
- rare
- anemia
- hypercholesterolemia
- fragility of large arteries
- bone demineralization (collagen- lysyl oxidase)
- demyelination
- menkes syndrome/ consuming excessive zinc
- shellfish, legumes, nuts, bran
- loss of Cu containing desaturase leads imbalance in sat/unsat FA
25
ceruloplasmin
- fe3+ to fe2+
| - helps it bind to transferrin
26
menkes disease
- mutation in Cu transporter ATP7A
- need for transport of copper into golgi to supply Cu enzymes like lysyl oxidase
- enzymes are secreted without copper and don't work
27
wilson's disease
- ATP7B
- copper overload
- copper not sequestered properly and accumulates in liver with severe liver and nervous system symptoms
- liver failure and cancer
- copper ring around eye
28
zinc
- cofactor for over 300 metalloenzymes
- plays structural role in many proteins- zinc finger domain
- meat, shellfish, nuts, legumes
29
zinc deficiency
- poor wound healing
- dermatitis-earliest sx, can be reversed, scaly
- reduced taste acuity
- poor growth
- impaired sexual development in kids
- alcoholics, elderly, ppl with malabsorption or kidney disease
30
chromium
- component of chromodulin- facilitates insulin binding to its receptor
- def-impaired glucose tolerance (from reduced insulin effectiveness)
- susceptible-ppl with impaired glucose tolerance
- Cr3+ hasn't proven helpful in trt type II diabetes
31
iodine
- incorporated into T3 and T4
- regulates BMR
- goiter, hyper/hypo thyroid
32
goiter
- low iodine stimulates increased TSH
| - enlarged thyroid
33
selenium
- component of antioxidant enzymes (glutathione peroxidase)
- component of deiodinase enzymes in metabolism of T3 and 4
- keshan disease (little selenium in soil)
- cardiomyopathy and cretinism
34
manganese
- arginase, pyruvate carboxylase
| - superoxide dismutase
35
molypdenum
-xanthine oxidase
36
fluoride
-bones and teeth strength
37
sulfur
component of aa and used in post translational modifications
38
children
iron and calcium
39
teens
Ca, Mg, vitamin A, C and B6
40
women
iron, calcium, Mg, B6, folate
41
elderly
B6, 12, D, zinc, chromium
42
alcoholics
-multiple, folate, B6, thiamine
43
drug/nutrients
-interactions should be considered- can affect absorption
