Vitamins Flashcards
1
Q
overview
A
- diverse group of organic molecules required in very small quantities for health, growth, and survival
- act as co-enzymes, symptoms of deficiency arise from loss of enzyme activity
- expand chemistry available in living systems
2
Q
DRI
A
- dietary reference intakes
- multiple tables that provide a global view of micronutrient requirements and toxic levels
3
Q
RDA
A
- recommended daily allowance
- one component of DRI
- defined as amount sufficient to meet the nutrient requirement of 97-98% of healthy individuals in a given group
- varies for different populations based on gender, age etc
- RDAs are reviewed and changed when research warrants
4
Q
optimal amt of vitamins
A
- cover a range
- deficiency
- biochemical parameters of def
- average
- nutrient-nutrient or nutrient-drug interactions
- toxicity symptoms
5
Q
how do deficiencies arise?
A
- poor nutrition
- increased demand
- problem with absorption of one or more vitamins
- interactions with meds
6
Q
lipid soluble
A
- ADKE
- structures resemble lipids
- generally stored more efficiently than water soluble
- deficiencies don’t arise as quickly
- toxicity may be a problem (A and D)
7
Q
water soluble vitamins
A
- B and C
- more hydrophilic structures
- in general, def arise more rapidly if vitamin is unavailable, they are excreted efficiently
- less likely to be toxic
8
Q
vitamin A
A
- visual cycle (rods and cones)
- synthesis of certain glycoproteins and mucopolysaccharides
- retinoic acid acts as hormone
- antioxidant
- from egg yolks, liver, butter, whole milk for retinol
- carotenoids from dark green and yellow veggies
9
Q
vitamin A def
A
- night blindness, xerophthalmia
- follicular hyperkeratosis
- anemia despite normal iron intake
- poor growth in children
- increased susceptibility to infection and cancer
- groups:poor, malnourished, premature babies
10
Q
vitamin A family
A
- beta-carotene
- all trans retinol
- all trans retinal
- 11-cis retinal (needed to vision cycle- goes to all trans when reacts with photon, loses opsin, nerve impulse)
- retinoic acid- gene transcription
- accutane (acne)
11
Q
vitamin D
A
- maintaining bone
- calcium homeostasis
- acts as a hormone
- receptors present in many tissues, full range unknown (cancer?)
- from sun, saltwater fish, liver, egg yolk, milk and butter fortified
12
Q
vitamin D def
A
- rickets/ osteomalacia-soft bones/ loss of minerals
- increased susceptibility to breast and other cancers, metabolic syndrome, diabetes, infection
- toxicity rare, but leads to high levels of calcium and bone loss
- poor, elderly, alcoholics
13
Q
vitamin D and cancer
A
- controversial area of very active research
- a number of studies show that low serum vitamin D levels, particularly in post menopausal women are correlated with increased risk of breast cancer
- some correlation between polymorphisms in the vitamin D receptor and certain cancers
- effects are postulated to arise from cell cycle signaling effects through the vitamin D receptor
14
Q
vitamin K
A
- localization of enzymes required for blood clotting
- helps catalyze addition of gamma-carboxyglutamate to clotting enzymes
- def-easy bruising, bleeding, hemorrhage
- newborn infants, patient on long term antibiotics, elderly and other with defects in fat absorption
- gastric bypass
15
Q
Quinone ring
A
- vitamin K
- phyllo- plants, kale- K1
- or mena-microbes, klebsiella-K2
16
Q
vitamin K and clotting
A
-essential for enzymes involved in GLA modification of clotting enzymes
17
Q
newborns/antibiotics and K
A
- lack intestinal bacteria that make K, might need supplementation
- poor absorption of fats may have insufficient vitamin K
18
Q
vitamin E
A
- antioxidant
- protects membranes from damage
- prevents oxidation of LDL
- from oils
19
Q
vitamin E def
A
- cardiovascular disease
- neuro symptoms
-patients with severe prolonged defects in absorption or genetic defects- celiac
20
Q
vitamin E family
A
- a-tocopherol actively maintained in the human body and is found in blood and tissues
- located in all cell and organelle membranes
- intercepts free radicals and prevents chain reaction of lipid destruction
21
Q
vitamin C
A
- cofactor for oxidases involved in collagen formation
- required for synthesis of steroids in stress (response to trauma)
- aids absorption of iron
- has antioxidant activity
- water soluble
- readily absorbed from food
- from citrus fruits, green veggies, tomatoes
22
Q
Vitamin C def
A
- mild bruising, immunocompromise
- SCURVY-decreased wound healing, osteoporosis, hemorrhage and anemia, fatigue
- corkscrew hairs and pinpoint hemorrgage
- periodontal disease
- poor diet/ increased need
- smokers
- long term treatment with aspirin, the pill, corticosteroids
23
Q
vitamin C and collagen biosynthesis
A
- required for prolyl and lysyl hydroxylases
- in order to make a triple helix of collagen
- hydroxylation of lysine and proline
24
Q
vitamin C and colds
A
- promoted by linus pauling
- little experimental evidence for prevention of colds, may shorten duration and/or moderate symptoms
- little toxicity in most people, can lead to GI upset and kidney stones
- higher RDA may help with promoting iron uptake and with antioxidant effects
25
Q
energy releasing B vitamins
A
1-thaimine 2-riboflavin 3-niacin biotin 5-pantothenic acid 6- pyridoxine
26
Q
hematopoietic B vitamin
A
9-folate
12- cobalamin
27
Q
common effects of def in energy releasing B vitamins
A
- symptoms show in rapidly growing tissues- skin- dermatitis, swollen red tongue, glossitis, GI- diarrhea
- nervous system also affected because of higher energy demand
- peripheral neuropathy
- depression, confusion
- lack of coordination
- malaise
- overlapping and distinct features
28
Q
thiamine
A
- B1
- required cofactor for several enzymes in cellular energy metabolism (TPP)-transketolase, pyruvate and a-ketoglutarate DH
- particularly critical in nervous system
- from yeasts, liver, whole grains, some bean, pork, and fish
29
Q
thiamine def
A
- mild: GI sx, depression, fatigue (poor, elderly)
- moderate: wernicke-korsakoff syndrom
- severe: beriberi-diet of polished rice, alcoholics
30
Q
wernicke korsakoff
A
- moderate/severe deficiency
- chronic alcoholics
- characterized by mental disturbance, unsteady gait, uncoordinated eye moements
- CHF
31
Q
beriberi
A
- severe
- wet-extreme muscle weakness, poly-neuropathy, heart failure, edema
- dry-no edema
32
Q
riboflavin
A
- B2
- precursor to FAD and FMN
- def-ariboflavinosis- rash around nose, IF of mouth and tongue, burning and itching eyes, light sensitivity
- alcoholics, but quite uncommon
- from milk, yogurt, cheese, meat, eggs, broccoli, asparagus, oranges and whole grain foods
33
Q
niacin
A
B3
- precursor of NAD and NADP
- given to patients with hypercholesterolemia or hypertriglyceridemia
- pellagra-dermatitis, dementia, diarrhea
- corn or millet based diets
- treated with trp or niacin
- from meat and other high protein foods, cereal grains
34
Q
biotin
A
- coenzyme for several carboxylases
- deficiency caused by eating a lot of rare eggs
35
Q
pantothenic acid
A
- B5
- required for synthesis of CoA
- required for TCA cycle and metabolism of all fats and proteins
- deficiency very rare, sx typical of B vitamins
36
Q
pyridoxine
A
- B6
- precursor of pyridoxyl phosphate (PLP)
- required for glycogen breakdown and synthesis of GABA and heme
- deficiency-mild-irritability, nervousness, depression
- severe-peripheral neuropathy, convulsions, decreased glu tolerance, hyper-homocysteinemia, anemia
- pts treated with isoniazid for TB susceptible
- from meat, egg yolk, veggies, whole grain cereal
