Chapter 9: Vitamins (overview + Vitamin C) Flashcards
organic, essential nutrients in minute amounts
aka “accessory growth factors”
do not yield energy when broken down but assist enzymes with energy production
vitamins
organic compounds present in small amounts and are essential for normal health and growth
vitamins
vitamins: gen charac and functions
not catabolized as a source of energy and are not used for structural purposes
many vitamins serve as _____
coenzymes
vitamins: gen charac and functions
most vitamins cannot be used in the form in which they are absorbed
some must be converted into its _____
ex: vitamin a
active form
vitamins: classification acc to solubility
includes vitamins a, d, e, k
fat-soluble vitamins
classification acc to solubility
include vitamin c and b-complex vitamins:
thiamin b1
riboflavin b2
niacin b3
pantothenic acid b5
pyridoxine b6
biotin b7
folate b9
cobalamin b12
water-soluble vitamins
related substances
2 group of compounds that are chemically related to vitamins and with of nutritional importance
provitamins
antivitamins
related substances
chemical precursors of vitamins that are converted with the body to active vitamins
ex: beta-carotene converted to vitamin a in the intestinal wall
provitamins
related substances
or antagonists are substances chemically related to true vitamins but cannot perform he biologic function of the true vitamins
ex: avidin present in raw and dried egg white that prevents the utilization of biotin
antivitamins
water-soluble vitamins
other names of vitamin c (4)
ascorbic acid
antiscorbutic factor
cevitamic acid
hexuronic acid
vitamin c: chemistry
a compound with _____ carbons closely related to the monosaccharide glucose
6 carbons
vitamin c: chemistry
vitamin is stable to _____ but easily destroyed by oxidation, light, alkali, and heat, esp. in the presence of iron and copper
these properties make it the most unstable vitamin
acid
vitamin c: chemistry
vitamin is stable to acid but easily destroyed by _____ (5), esp. in the presence of iron and copper
these properties make it the most unstable vitamin
oxidation, light, alkali, and heat
vitamin c: chemistry
vitamin is stable to acid but easily destroyed by oxidation, light, alkali, and heat, esp. in the presence of _____ and _____
these properties make it the most unstable vitamin
iron and copper
vitamin c: chemistry
exist in 2 forms
the oxidized form, dehydroascorbic acid, also has vitamin c activity
reduced and oxidized
vitamin c: chemistry
high levels of vitamin c are found in? (4)
pituitary and adrenal glands, eyes, white blood cells, and brain
vitamin c: absorption, transport, and utilization
absorbed in the _____ by sodium-dependent active transport system; a simple diffusion at a lower rate
jejunum
vitamin c: absorption, transport, and utilization
absorbed in the jejunum by _____; a simple diffusion at a lower rate
sodium-dependent active transport system
vitamin c: absorption, transport, and utilization
the degree of absorption decreases as the intake increases.
On average, about 90% of the nutrient is absorbed when the daily intake ranges between _____
20-120 mg
vitamin c: absorption, transport, and utilization
unabsorbed vitamin c in the large intestine creates an _____ like sugars resulting in watery stools or diarrhea
osmotic effect
vitamin c: absorption, transport, and utilization
unabsorbed vitamin c in the large intestine creates an osmotic effect like sugars resulting in _____ or _____
watery stools or diarrhea
vitamin c: absorption, transport, and utilization
transported in the _____, moving freely into body cells
blood
vitamin c: absorption, transport, and utilization
concentration is found in the ____ and the _____; tissue concentration exceeds the plasma level by 3-10 times
adrenal gland; retina
vitamin c: absorption, transport, and utilization
consumption of _____ per day can increase the total body pool to a level of 1.2-2.0 g that is sufficient to protect the body from scurvy for 90 days
100 mg
vitamin c: absorption, transport, and utilization
consumption of 100 mg per day can increase the total body pool to a level of _____ that is sufficient to protect the body from scurvy for 90 days
1.2-2.0 g
vitamin c: absorption, transport, and utilization
consumption of 100 mg per day can increase the total body pool to a level of 1.2-2.0 g that is sufficient to protect the body from scurvy for _____
90 days
vitamin c: absorption, transport, and utilization
vitamin c deficient diet declines the pool at a rate of about 3% a day until it reaches _____; signs of scurvy start to appear
300 mg
vitamin c: absorption, transport, and utilization
the body maintains a plasma vitamin c level of
1.2-1.5 mg/100 ml
vitamin c: absorption, transport, and utilization
degradation products
diketo-l gulonic acid
vitamin c: absorption, transport, and utilization
excess and unmetabolized vitamin is excreted in the
urine
relationships with other nutrients
prevents the oxidation of (4)
vitamins a, c, folic acid, and polyunsaturated fatty acids
relationships with other nutrients
prevents the oxidation of THF
tetrahydrofolate
relationships with other nutrients
facilitates the utilization of (3)
iron, calcium, folic acid
functions
important antioxidant that protects the body from
damaging oxidizing agents
functions
formation of _____, the fibrous structural protein in the connective tissues which serves as the matrix on which the bone and teeth are formed
collages
functions
synthesis of _____, a compound that participates in the transport of fatty acids into mitochondria
carnitine
functions
hormone and neurotransmitter synthesis (3)
steroids, catecholamine, serotonin
functions
operates in the metabolism of certain amino acids which may end up being converted to the hormones _____ and _____
norepinephrine and thyroxin
deficiency
symptoms include petechiae, swelling, infection, bleeding of gums, and muscle pains
other deficiency symptoms include anemia, lower resistance to infection, depression, and rough skin
those who do not consume sufficient quantities of fruits and vegetables
smoking (generates free radicals), hence elevated requirements for vitamin c
scurvy
toxicity
high levels of intake result in nausea abdominal cramps, diarrhea, fatigue, insomnia, hot flashes, rashes in skin, interference with medical tests, aggravation of gout symptoms, excessive urination and kidney stones
-
food sources
ripe papaya, citrus fruits, raw cabbage, tomatoes, guava, mango, cantaloupes, strawberry, sweet pepper, turnips, potato, and organ meats (liver and kidney)
recommended intake for children ages (1-12)
45 mg both male and female
recommended intake for school-age children and adolescents
55-60 mg
recommended intake for adolescents, adults, and old age
60 for females
70 for males
recommended intake for pregnant
60 +10
recommended intake for lactating
60 +35