Nutrition: Vitamins and Minerals Flashcards
What are the two water soluble vitamins?
b and c
Water soluble vitamins are excreted once concentration surpasses the ____ ____
renal threshold
Metabolic stores labile, depletion occurs in weeks or months. Deficiencies show up quickly on inadequate diet. True or false?
true
B-complex and vitamin c are not stored in the body and must be replaced everyday. True or false?
true
Thiamin (B1) is is rapidly converted to ____ ____ and ____ ____
thiamine pyrophosphate; thymine triphosphate
A symptom of thiamine deficiency is loss of appetite, constipation, nausea, mental depression, fatigue - this set of symptoms is referred to as ____-____ syndrome
Wernicke-Korsakoff
Severe thiamin deficiency leads to beriberi disease. What type of population is this seen with?
population that rely on polished rice and alcoholics
Dry beriberi can cause ____ ____ and it is considered wet beriberi when coupled with _____
muscular dystrophy; edema
Both forms of beriberi lead to ___ failure
heart
note: coffee and tea destroy thiamin
Riboflavin (B2) is a recourse of ____ and ____ - both are coenzymes
FAD; FMN
Riboflavin is required for ___ mobilization so deficiency contributes to anemia
iron
Symptoms of Riboflavin deficiency include?
scaly dermatitits, glossitis
note: chronic alcoholism can lead to deficiency
_____ slows conversion of riboflavin to FMN and FAD
hypothyroidism
Niacin (B3) is not a vitamin in strict sense - it can be synthesized from ____
Trp
60 mg Trp -> 1 mg Niacin….. not very efficient
What does Trp require to synthesize Niacin?
pyridoxine, riboflavin, and iron
Dietary niacin and niacinamide are converted to ___ and ___
NAD; NADP
Deficiency of Niacin causes ____ of tongue
glossitis (redness)
The disease associated with Niacin deficiency is pellagra. What three D’s are seen with pellagra?
dermatitis, diarrhea, dementia
Pyridoxine, pyridoxamine, and pyridoxal are naturally occurring forms of vitamin ___
B6
Pyridoxine is required for the synthesis of what NTs?
serotonin, NE, Epi, GABA
note: also required for myelin formation
Deficiency of pyridoxine causes what symptoms?
irritability, nervousness, and depression in mild deficiency
convulsions in severe deficiency
____ is covalently bound to an amino group of lysine residue in carboxylase of pyruvate, acetyl-CoA, and propionyl-CoA
biotin
Where is biotin found and synthesized?
found in peanuts, chocolate, and egg
synthesized by intestinal bacteria
Folic acid in diet usually occurs as _____ derivatives with 2 to 7 ___ acid residues joined in gamma-peptide linkages
polyglutamate; glutamic
What enzyme removes extra glutamate in the intestine?
folypoly-gamma- glutamate carboxylase II
The monoglutaminated folic acid is taken up by reduced folate carrier into what cells?
intestinal mucosa
Folate deficiency inhibits what?
DNA synthesis by decreasing availability of purine
note: neural tube birth defects, cervical and colon cancer
Vitamin B12 contains ___ and its derivatives
B12
B12 deficiency results in accumulation of both ____ and ____ acid
homocysteine; methylmalonic
In foods, B12 is bound to proteins in the ____ or ____ form
methyl; 5’-deoxyadenosyl
note: must be released from protein by hydrolysis in the stomach or trypsin digestion in the intestine
A Cobalamin (B12) deficiency causes what?
pernicious anemia with neurological deterioration caused by demyelination of nervous tissue
Vitamin C is a cofactor for oxidases involved in what?
hydroxylation of lysine and proline, synthesis of carnitine, and NE
Hydroxylation of Lys and Pro is required for ____ to cross-link properly
procollagen
Vitamin C is required for maintenance of normal CT and for wound healing, and bone formation. true or false?
true
Ascorbic acid-water soluble vitamins (vitamin C), when dysfunctional, cause the most severe symptoms of ____
scurvy
____ may act as an antioxidant against oxidative stress
ascorbate
How does scurvy present?
formation of brown spots on skin, spongy gums, and bleeding from all mucous membranes
What is the time from for onset of scurvy symptoms?
1-6 months depending on vitamin C storage level in body to begin with
Ascorbic acid is required for a range of essential metabolic reactions and is absorbed by both ____ ____ and ____ diffusion
active transport; simple
Without ____ ____, gums would bleed because blood vessels need collagen and teeth would fall because they depend on collagen for their attachment to the gingiva
ascorbic acid
What are the fat soluble vitamins?
Vitamins A, D, E, and K
Retinol, retinal, and retinoid acid are the active forms of vitamin ___
A
Precursors of vitamin A are synthesized by plants as ____, some are cleaved to retinol and stored in the liver as ___ ____
carotenoids; retinol palmitate
Liver, yolk, butter, and milk are good sources of ___; ____ are found in dark green and yellow veggies
retinol; carotenoids
At low oxygen tensions, ___-___ is very effective antioxidant against cancers initiated by free radicals
beta-carotene
In addition to direct role of vitamin A in visual cycle, carotenoids lutein and zeaxanthin reduce the risk of ___ ____
macular degeneration
Retinyl phosphate is required for synthesis of glycoproteins. This is an important component of ___
mucus
Retinol and/or retinoid acid down regulate the synthesis of ___
keratin
Retinol and/or retinoid acid are required for the synthesis of iron transport protein ___
transferrin
note: thus vitamin A deficiency can lead to anemia
Night blindness is an early symptom of vitamin ___ deficiency
A
Severe deficiency of vitamin A leads to progressive keratinizaiton of the cornea, known as ____
xerophthalmia
Vitamin A accumulates in the liver where it can become toxic. What are some of the symptoms?
bone pain, scaly dermatitis, enlargement of liver and spleen, nausea, and diarrhea
Vitamin D is a group of fat-soluble vitamin responsible for enhancing what?
intestinal absorption of calcium, iron, magnesium, phosphate, and zinc
note: D2 and D3 are most important
Vitamin D is synthesized in the skin from ___ from sun
cholesterol
In the liver, D3 is converted to ____; D2 is converted to ____
calcidiol; 25-hydroxyvitamin D2
Part of the calcidiol is converted by the kidneys to ___, the biologically active form of vitamin D
calcitriol
Calcitriol circulates as a hormone in the blood, regulating what?
concentration of calcium and phosphate in the blood stream and promoting the healthy growth and remodeling of bone
Insufficient sun exposure causes ____ which is softening of the bones
osteomalacia (rickets in children)
note: can be from deficiency in calcium, phosphorus, or vitamin D
Vitamin D toxicity causes hypercalcemia. What are the main symptoms?
anoxrexia, nausea, vomitting, weakness, renal failure
note: mental retardation can be seen in young children along with abnormal bone growth
___ is the continued formation of osteoid matrix and cartilage that are improperly mineralized resulting in soft liable bones. ____ is demineralization of preexisting bones
Rickets; osteomalacia
In regards to osteomalacia and osteoporosis, osteoid matrix remians intact in ___ but not in _____
osteomalacia; osteoporosis
Vitamin E occurs as tocopherols and tocotrienols, which are ____
antioxidants
alpha-tocopherol is potent against what?
ROS
gamma-tocopherol is potent against what?
Reactive nitrogen species
Tocopherols and tocotrienols also prevent oxidation of LDL which does what?
reduces risk of cardiovascular disease
In regards to Vitamin E deficiency, what type of symptoms can occur with prolonged deficiency associated with malabsorption disease
neurological
True or false? Vitamin E can act as an anticoagulant, increasing the risk of bleeding problems.
true
In combination with certain drugs such as ___, hypervitaminosis E can be life-threatening. It may also counteract vitamin ___, leading to a deficiency
aspirin; K
Vitamin K occurs as K1 in ___ vegetables and K2 in ____ bacteria
green; intestinal
Vitamin K is required for the conversion of ____ acid to __-___ acid
glutamic; gamma-carboxyglutamic
gamma-carboxyglutamic acid residues are good ___ and allow the proteins to bind ___ required for their biological activity
chelators; Ca2+
In carboxylase reactions, the active hydroquinone form of vitamin K is converted to what?
inactive 2,3 epoxide form
note: regeneration requires K epoxide reductase
Vitamin K is essential in blood ___
coagulation
note: this is why deficiency causes increased coagulation time
Where do vitamin K1 and K2 accumulate?
K1: liver
K2: peripheral tissues
The most common vitamin K deficiency occurs in which individuals
newborn infants and in patients with obstructive jaundice and diseases leading to malabsorption and long-term antibiotic therapy
This is the most abundant mineral in the body. Mostly in bone, small amount outside of bone functions in a variety of essential processes
Ca2+
Low serum Ca2+ stimulates formation of what?
1,25-dihydroxycholecalciferol - enhances intestinal Ca2+ absorption
Vitamin __ is required for optimal utilization of calcium
D
True or false? exercise facilitates calcium utilization for bone formation
true
Symptoms of Ca2+ deficiency resemble those of vitamin __ deficiency
D
Bone density reaches its maximum between what years?
10-35
This mineral is required for many enzyme activities, particularly those utilizing an ATP complex and for neuromuscular transmission. This mineral is significantly reduced during processing of food items.
Magnesium
Deficiency of Mg2+ occurs in _____, with use of certain diuretics and metabolic acidosis
alcoholism
The main symptoms of Mg2+ deficiency are what?
weakness, tremors, and cardiac arrhythmia
Supplemental Mg2+ can help prevent formation of calcium oxalate ___ in the kidney
stones
Iron is a component of ___ in hemoglobin and myoglobin, which are essential for O2 transport
heme
Total body iron in human adults is __-__ g. Erythrocytes normally live only ____ days; meaning erythrocytes containing 20 mg of iron are destroyed each day
3-4; 120
The net loss of iron for males and postmenopausal women is shedding of intestinal and skin cells, which amounts to about __-__ mg/day
1-2
Assuming a 10-15% efficiency of Iron absorption, an RDA of ___ mg/day for normal adult males and ___ mg/day for menstruating females has been set. For pregnant females, it is ___ mg/day
8; 18; 27
Patients develop ____ degeneration and ___ due to increased iron in the pancreas and brain
retinal; diabetes
_____ is primarily a genetic disease of iron overload. Patients with this disease develop iron deposits in the liver, heart, and endocrine tissue even though they have normal intakes of dietary iron.
hemochromatosis
Treatment for hemochromatosis consists of regular ___, which is effective at preventing the symptoms of hemochromatosis if started early enough. People with hemochromatosis are also advised to avoid foods and supplements containing high levels of iron or vitamin ___
phlebotomy; C
There are a number of clinical tests that can be used to determine iron status. What is the normal range for males and females for hemoglobin?
males: 13.8-17.2 gm/dl
females: 12.1-15.1 gm/dl
What is the normal hematocrit range for males and females?
males: 36.1-44.3%
females: 40.7-50.3%
note: hematocrit is % of RBCs found in whole blood
Iron-deficiency anemia is characterized as _____ _____ anemia, meaning that the RBCs are smaller and paler than normal due to their decreased hemoglobin content
microcytic hypochromic
Dietary iodine is efficiently absorbed and transported to the ___ gland
thyroid
Thyroid hormones function in regulating what?
basal metabolic rate of adults and the growth and development of children
____ fish are the best natural food sources of iodine and in the past population groups living in inland areas suffered from the endemic deficiency disease called ___
saltwater; goiter
____ is part of the catalytic center of over 300 metalloenzymes, including RNA and DNA poly
zinc
Zinc fingers provide what to proteins?
structural stability and are also important for protein-protien interactions (signal transduction)
Relatively large amounts of loosely bound zinc are also found in vesicular structures including?
synaptic vesicles of nerve terminals and cells of islets of langerhans
Intracellular zinc levels are controlled in part by a group of 14 transporters called ____ which transport zinc into cells and 10 transporters called ____ which control the efflux of zinc from the cytosol to extracellular space
ZIPs; ZnTs
Zinc deficiency in children is usually marked by what?
poor growth and impairment of sexual development; also poor wound healing and dermatitis
Zinc is present in ____, a salivary polypeptide that appears to be necessary for normal development of taste buds
gustin
Zinc is required for ___ production by monocytes and T cells
cytokine
In lead poisoning, lead replaces the zinc which leads to ____
anemia
Severe zinc deficiency is seen primarily in ____ patients with chronic renal disease
alcoholic
The most characteristic early symptom of zinc-deficient patients on long term parenteral nutrition (TPN) is ___
dermatitis
Ceruloplasmin and hephaestin are important copper-containing enzymes that do what?
oxidize iron to facilitate its binding to transferrin
Dopamine beta-hydroxylase is an important copper-containing enzyme that does what?
NE synthesis
Lysyl oxidase is an important copper-containing enzyme that does what?
collagen cross-linking
Tyrosinase is an important copper-containing enzyme that does what?
pigment formation
anemia, hypercholesterolemia, demineralization of bones, leukopenia, fragility of large arteries, and demyelination of neural tissue are all symptoms of what?
copper deficiency
Copper deficiency is relatively rare and is usually only seen because of excess ___ intake
zinc - zinc and copper compete for absorption
____ disease is an x-linked disorder characterized by global copper deficiency
Menkes
What mutation causes Menkes disease?
ATP7A copper transporter - interferes with the ability of intestinal mucosal cells to transport copper into the bloodstream
What are the symptoms of Menkes disease?
mental retardation, growth retardation, hypothermia, loos skin and joints, hypo pigmentation, and kinky hair
____ disease is an autosomal recessive disease characterized by copper overload, particularly in the liver and the brain
Wilson
What mutation causes wilson’s disease?
ATP7B copper transporter that prevents the liver and neurological tissue from getting rid of excess copper
What are the signs of Wilson’s disease?
liver failure, seizures, psychiatric symptoms, characteristic gold-brown ring called the Kayser-Fleischer ring around the periphery of the cornea
____ is a component of the low-molecular-weight protein chromodulin which potentiates the effects of insulin by facilitating insulin binding to its receptor and receptor kinase signaling
chromium
The chief symptom of chromium deficiency is what?
impaired glucose tolerance, a result of decreased insulin effectiveness
Selenium is one of the few nutrients not removed by the milling of flour and is usually though to be present in adequate amounts in the diet. True or false?
true
Selenium supplementation may reduce the risk of what cancers?
lung, breast, and bladder
____ is a component of arginase, glutamine synthetase, Mn superoxide dismutase, and phosphoenylpyruvate decarbyxlase and activates a number of other enzymes
mangansese
______ is present in xanthine oxidase
molybdenum
____ appears to be important for bone formation, nerve function, and immune response
boron
