L19 Vitamins Flashcards
What are vitamins
micronutrients required for normal function
derived from diet
TF: All lipid-soluble vitamins are organic compounds
True
What are some lipid-soluble vitamins
A, E, D, K
TF: Large amounts of vitamin are required for healthy function
False, only small amounts are required
TF: Vitamins are a source of energy
False
TF: Food preparation can decrease the amount of vitamins available for absoprtion
True
What are some factors that affect the absorbability of vitamins?
Source (plant vs animal)
Sunlight (D)
Moisture
Growing conditions of plant
Plant maturity at harvest
Packaging & storage
TF: Calcium is important for Vitamin D absorption
False, other way around
Which vitamin requires sunlight for absorption
D
What is flour fortified with
niacin and folate
What are some reasons for vitamin deficiency
Food processing, storage, diet, drug interactions, disease, physiological state
genetics: lack of certain enzymes
What is the closest we’ve gotten to personalized medicine
identifying needs in individuals for vitamins
what is a provitamin? example?
an inactive form of a vitamin that the body needs to activate
e.g. beta-carotene which is cleaved half to form two molecules of vitamin A
What are the 2 major subcategories of vitamins?
water-soluble and lipid-soluble
Which system circulates vitamins
lymphatic system (which then deposits vitamins into the circulatory system/blood
Why are fat-soluble vitamins possibly dangerous (unlike water-soluble vitamins)
they can accumulate in the body which can cause severe toxic effects
water-soluble vitamins do not build up as they can be peed out
TF: water-soluble vitamins enter the lymphocyte before entering circulation
False, they enter the bloodstream directly
In which part of the GIT are vitamins solubilized
duodenum (first part of SI)
how are lipid-soluble vitamins transported throughout the body
in micelles and chylomicrons (enterocyte and beyond)
What catalyzed the release of fat-soluble vitamins from their esters?
pancreatic esterase (in presence of bile salts)
At high doses, vitamins _ and _ can be absorbed directly from water-miscible emulsions
A and E
What kinds of diseases can cause decreased absorption of fat-soluble vitamines
intestinal, biliary, pancreatic diseases
What is Vitamin A important for? (6)
- night and day vision (becomes part of the retina)
- immune function (leukocyte production)
- cell proliferation and differentiation (regulates enzyme production, blood carrier proteins, structural proteins)
- skin (epithelial cells)
- reproduction (maintains fertility, allows for sperm production, embryo development)
- bones (osteoclast increase)
Vitamin A is a precursor for _
rhodopsin, photopigment found in rods of the retina which help for night vision
The lack of which vitamin can cause night blindness
A
Our ability to see is dependent on what?
rod and cone photoreceptors in the posterior aspect of the eye
By what ratio do cone outnumber rod photoreceptors?
Trick question, rods outnumber cones by 20:1 ratio
How many layers of the retina must light pass through
10
which photoreceptor is used for day vision?
cones
photoreceptors are composed of…
nucleus and outer segment composed of discs that contain light-absorbing photopigments
Vitamin A deficiency can result in… (7)
- xerophthalmia (inability to see) - eye issues
- hyperkeratosis (keratin disease) - skin issues
- vulnerability to infection
- growth retardation
- Bone deformation
- Defective teeth
- Kidney stones
What are symptoms of vitamin A deficiency (10)
fatigues, vomiting, abdominal pain, bone + joint pain, loss of appetite, skin disorders, headaches, blurred/double vision, liver damage, skin discoloration
TF: vitamin A is a teratogen
True, can cause birth defects like cleft palate and heart abnormalities
TF: acne treatments could possibly be a cause of excess vitamin A
true, retinoids and acutane
Too much vitamin A has been implicated in…(4)
increased risk of hip fracture in postmenopausal women, lung cancer, cardiovascular mortality, total mortality
Vitamin D is activated in _ to make its active form _
liver and kidneys, 25-hydroxyvitamin D (25(OH)D)
What are the functions of vitamin D
- bone health and production (D3 facilitates calcium absorption)
- protection against chronic diseases
- regulates insulin formation and secretion
TF: overdose in vitamin D can help protect against certain cancers
False,
but effective in rodent models
What are some dietary sources for vitamin D
oily fish, egg yolk, animal liver
TF: vitamin D can be synthesized from the skin
True
Vitamin D increases absorption of _ and _. It also stimulates _ by _
calcium, phosphorus
calcium retention by kidneys
Vitamin D is excreted in _
bile, urine
What happens when vitamin D reaches its target tissue
it binds to the nuclear vitamin D receptor, complex is then taken into the nucleus to dimerize with the retinoid X receptor (RxR), this then interacts with the VDR response element to alter gene expression
What is vitamin D deficiency associated with
rickets (children): causes bowed legs
osteomalacia and osteoporosis (adults)
> soft bones
What does vitamin D toxicity cause
hypercalcemia: causes kidney stones and psychiatric overtones (uncommon)
TF: Vitamin D can decrease cancer progression and prevent cancer
False
Which family of vitamin E is required by humans
alpha-tocopherol
Which vitamins are mainly stored in body fat
A, D, E
(K is mainly stored in liver)
What is the main function of vitamin E
antioxidant, protecting cell membranes from free radicals
potentially lowers to the risk of chronic diseases
- defends cell membranes, lungs, DNA, heart (protects against lipid per oxidation), eye, liver, breast, muscle)
maintains beta-carotene (vitamin A provitamin) antioxidant activity
What is the recommended amount of vitamin E for adults
15 mg / day
19 mg / day for breastfeeding women
What are some dietary sources for vitamin E
nuts, seeds, vegetable oil, whole grains, wheat germ oil, fruit, vegetables, animal products
TF: vegans are at risk of vitamin E deficiency
true, unless they replace them
What disease can cause vitamin E deficiency
problems with fat absorption (intestinal, biliary, pancreatic), chronic gut diseases (Crohn’s), rare genetic disorder
TF: Vitamin E toxicity is detrimental
False, but can interfere with blood clotting at very very high levels (rare)
TF: oral consumption of Vitamin E is not safe when added in e-cigs
True, causes lung injury
What is another name for vitamin K
phylloquinone
TF: Vitamin K comes in 5 forms
False, only K1 and K2
What are the main functions for vitamin K
bone health and blood clotting
What is the dietary recommendation for vitamin K
120 mg/day (men)
90 mg/day (women)
Which vitamin is necessary for the synthesis of thrombin from its precursor prothrombin (as well as other clotting factors)
K
TF: Deficiency in vitamin K leads to excessive blood clotting
False, it causes excessive bleeding
Vitamin K is necessary for the synthesis of clotting factors)
What is warfarin and with which vitamin does it interfere with
it is an anticoagulant drug that interferes with vitamin K
What are some food sources for vitamin K
green veggies and plant oils
also produced in intestinal bacteria
Why are some newborns at risk of vitamin K deficiency
lack of vitamin K in breastmilk (formula is fortified with vitamin K)
What can vitamin K toxicity cause
interference with anticoagulant medications
Which are the water-soluble vitamins? What are their functions
B (8) and C
B: coenzymes in energy metabolism
C: antioxidant and stabilizes vitamin E
What are oxidants
reactive molecules that can react with protein, DNA, lipids and other cellular molecules
When doing so, these molecules are damaged (free radicals) and can cause disease and inflammation
Describe vitamin B1
thiamin
part of the coenzyme thiamine pyrophosphate (TPP) which helps glucose breakdown, makes RNA, DNA, and synthesize/regulate neurotransmitters
1.1, 1.2, 1.4, 1.5 (men, women, pregnant women, breastfeeding women)
What are food sources for vitamin B1
pork, legumes, nuts, seeds, fish, seafood, grain products
cooking reduces availability
What is Beriberi
vitamin B1 deficiency, characterized by profound muscle weakness and nerve destruction
headache, irritability, depression, loss of appetite
Describe vitamin B2
riboflavin
coenzyme in energy metabolism and supports antioxidants
Food sources for vitamin B2
milk, dairy, enriches grains, eggs
Why are foods that are high in riboflavin stored in opaque containers?
riboflavin is broken down by light
Which vitamin B must be stored in opaque containers
B2
What is vitamin B2 deficiency called
ariboflavinosis, common in alcoholics
skin disorders, excess blood (hyperemia), edema of the mouth and throat, angular stomatitis (lesions at the corners and inside mouth), cheilosis (swollen, cracked lips), air loss, reproductive problems, sore throat, itchiness, redness
What is vitamin B3 also known as? describe its function? what foods is it found in
niacin
coenzyme in energy metabolism and supports FA synthesis
enriched rains, meat, poultry, fish, nuts, peanuts
What is pellagra
vitamin b3 deficiency condition
Four Ds: dermatitis, diarrhea, dementia, death
severe deficiencies only ^
Deficiencies in what vitamins can worsen pellagra symptoms
pellagra = vitamin B3 deficiency
worsened by deficiency in B1, B6, or iron
High doses of which vitamin can treat high blood cholesterol?
B3 (niacin)
Which amino acid is a precursor for niacin (B3)
tryptophan
Toxicity in which vitamin B can cause skin flushing and liver damage?
B3
Vitamin A as well
What is vitamin B6 also known as? describe its function. What foods is it found in?
pyridoxine
Part of PLP, coenzyme in protein and amino acid metabolism as well as gluconeogenesis
helps produce non-essential amino acids, neurotransmitters, hemoglobin
helps lower levels of homocysteine
meat, fish, poultry, potatoes, fortified meat substitutes, bananas, sunflower seeds (important in meat sources, thus absent in plant based diets)
What is vitamin B6 deficiency characterized by
microcytic hypochromic anemia, heart disease (due to high homocysteine levels), damage to nervous system, depression, headaches, confusion, convulsion
Vitamin B6 toxicity can result in…
(pyridoxine toxicity) subtle neurological damage, upset stomach, headache, sleepiness, tingling, prickling, burning sensation
Describe folate, its function, and where it can be found in diet
vitamin B9
coenzyme in DNA synthesis, cell division, amino acid metabolism, normal RBC maturation
fortified cereals, enriched grains, green leafy vegetables, orange juice, sunflower seeds, legumes
Which vitamins work to control homocysteine levels
B6, B12, B9
Folate (B9) deficiency is associated with…
megaloblastic anemia (RBC cannot mature), diarrhea, birth defect in infants (spina bifida)
Vitamin B12 deficiency can be masked with _
folate supplements
folate supplements can mask vitamin _ deficiency
B12
Folate toxicities is common in _ and can cause _
hypersensitive people, or people with poor nutrition
hives, respiratory depression
Development of the spine is encouraged by which vitamin
folate (B9)
Describe vitamin B12, its function, where its found
cobalamin (refers to cobalt containing compounds)
needed for normal folate function, helps maintain myelin sheath around nerve axons
found only in animal foods: meats, liver, milk, eggs
absorption requires intrinsic factor
TF: deficiency in vitamins B9 and B12 is associated with spina bifida
False, only B9, not B12
How is vitamin B12 broken down
in stomach, forms complex with haptocorrin from salivary glands
complex taken into SI where it is split and complexes with intrinsic factor
Majority of vitamin B12 is released in _
feces, rest is taken up by gut endothelium into bloodstream
Vitamin B12 deficiency can lead to
cobalamin deficiency (cobalamin = B12), pernicious anemia -> nerve damage + megaloblastic anemia (enlarged RBC)
Describe vitamins B5 and B7, what their functions are and where they are found
B5: pantothenic acid, component of coenzyme A, widespread in foods (reduced by freezing, canning, or refining)
B7: biotin, coenzyme for metabolism of glycogenic amino acids and FA and DNA synthesis + plays a role in energy release from FA. found in cauliflower, liver, peanuts, cheese
What compound can prevent absorption of vitamin B7
raw egg whites (protein avidin)
Describe vitamin C, its functions, where it is found
ascorbic acid
antioxidant, collagen synthesis, enhances iron absorption from plants, synthesis of steroid hormones, thyroid hormones, bile salts and parts of DNA
citrus fruits, strawberries, kiwi, fortified juice, broccoli, tomatoes, potatoes, cabbage, leafy greens, peppers
Who is Linus Pauling
some guy who believe vitamin C excess was healthy on the basis the it is water-soluble so its not protein-bound in the blood
TF: vitamin C can help reduce the duration of a cold
False, it is not fully proven
also note: that vitamin C does not protect against actually catching a cold
What are symptoms of scurvy
loss of teeth, pale skin, sunken eyes, muscle deterioration, organ failure, death
TF: scurvy refers to vitamin C toxicity
False, deficiency
TF: Taking high doses of vitamin C has no adverse effects
false, it can cause GI distress (puking)
TF: hesperidia, pangamic acid, rutin all help in boosting our health
False!!!! BOGUS!!!
