unit 5- vitamins Flashcards
(93 cards)
1
Q
vitamins
A
- organic compounds that are vital to life and indispensable to body fxn
- only needed in minute amounts, and are non-caloric, essential nutrients
2
Q
2 classes of vitamins
A
1) fat soluble
2) water soluble
-the solubility of a vitamin confers on its many characteristics and determines how it is absorbed, transported, stored and excreted
3
Q
fat soluble vitamines
A
ADEK
- dissolve in lipid and require bile for absorption
- absorbed into lymph and travel through blood with protein carriers
- they are not readily excreted, tend to build up and therefore higher risk for toxicity
4
Q
can fat soluble vitamins collect up?
A
-can be stored in liver or with other lipids in fatty tissues, and can build up to toxic amounts
(therefore caution fat soluble supplements)
5
Q
3 active forms of vitamin A in body
And what are food sources of Vit A
A
1) retinol
2) retinal
3) retanoic acid
-preformed vit A is only found in foods of animal origin (liver and fish oil, as well as milk (lost when skim), cheese, and fortified cereal
6
Q
retinol
A
-stored in liver, and the body’s cells convert retinol to the two other active forms
7
Q
b-carotene
A
- found in plant foods (i.e. orange veggies such as carrots, sweet potatoes and apricots; and dark green veggies like spinach and broccoli; and other colour veggies such as iceberg lettuce, beets, and sweet corn)
- can be converted to vitamin A
8
Q
vitamin A functions
A
-gene expression, vision, cell differentiation, reproduction and growth, and immunity
9
Q
Vitamin A toxicity
A
- chronic intake of even small excesses can weaken bones and contribute to hip fractures
- pregnant women must use caution as it can cause malformations to fetus
- children are the most sensitive to toxicity
10
Q
Vit D
A
- cholecalciferol
- UV light from sun can convert cholesterol in human skin into Vit D precursor, which is absorbed into blood
- liver and kidneys then finish converting precursor to active Vit D
11
Q
D functions
A
- hormone
- plays role in regulating blood calcium and phosphorus levels, thus maintaining bone integrity
12
Q
D deficiency
A
- low levels may be linked to high bp, some types of cancer, T1D, heart disease, RA, IBD, and even MS
- the well established problems are calcium balance and bones=> rickets in children and osteomalacia in adults
13
Q
what does the risk of vit D deficiency increase with?
A
age
-due to lower intake, housebound, decreased ability to activate vit D, and need increases after 50
14
Q
Vit D toxicity
A
-most potentially toxic of all vitamins (but no risk just form sun)
15
Q
factors that affect conversion to active Vit D from sun?
A
-skin tone, sunscreen use, pollution, clothing, geography, and time of year
16
Q
Food sources of Vit D
A
- fortified milk and margarine, eggs, butter, fortified soy beverages (some rice and almond beverages), as well as some fatty fish
- more foods are starting to be fortified
17
Q
is breast milk high or low in Vit D
A
-low (therefore supplementation of breasted infants is recommended)
18
Q
Vit E
A
-tocopherol (god standard= alpha version)
19
Q
function of Vit E
A
- antioxidant (main defender against oxidative damage)
- especially important in RBC and lungs (high exposure to oxygen)
- may protect LDL from oxidation and reduce inflame (thus protecting against heart disease)
20
Q
Vit E deficiency: rare or common
A
rare (usually only occurs in premature infants)
21
Q
why is Vit E deficiency rare?
A
3 reasons:
1) found in many foods
2) body stores enough in fatty tissue to last a long time
3) cells recycle their working supply of vitamin E, using the same molecules over again
22
Q
Vit E toxicity
A
rre
-no adverse affects reported from naturally occurring Vit E
23
Q
when is Vit E toxicity more likely to occur?
A
frm supplements and fortified foods
24
Q
Food sources of Vit E
A
MANY:
-vegetable oils, f+v, fortified cereals/grains, meats+alts, and milk products
25
what destroys Vit e?
heat processing and oxidation
26
Vit K functions
- help synthesize proteins that help clot the blood
| - also needed for synthesis of key bone proteins
27
Vit K Deficiency
-few have
28
why are infants given a dose of Vit K at birth
- they are born with sterile intestinal tract, and vit K producing bacteria take weeks to establish
- give to prevent hemorrhage
29
Vit K toxicity
-rare (no upper limit set)
30
Vit K sources
- intestinal bacteria
| - dark, leafy greens, and members of cabbage family
31
which 2 fat soluble vitamins can be derived from non-food source?
Vid D and K
32
water soluble vits
- C and B
- dissolve in water, so they are absorbed into blood stream where they travel freely
- most not stored; are excreted in urine
- less risk of toxicity; needed in frequent doses
33
The B Vitamins
- act as coenzymes, and some are also involved in energy metabolism
- play important roles in body, and typically deficiencies occur together, as many food sources contain a combo of the Bs
34
In north america, which product is fortified by vit B
-refined grain products
35
Thiamin function
- plays critical role in energy metabolism of all cells
| - occupies site on nerve cell membranes therefore, nerve processes and muscles depend heavily on thiamin
36
thiamin food sourses
-small amounts occur in many nutritious foods, such as legumes, enriched/whole grain cereals, sunflower seeds and pork
37
thaimin deficiency
= beriberi
-characterized by loss of sensation in the hands and feet, muscular weakness, advancing paralysis and abnormal heart action
38
Wernicke-Korsakoff
-severe thiamin deficiency, seen in those who abuse alcohol (as it impairs the absorption of thiamin from the digestive tract and speeds up its excretion in the urine)
39
Thiamin toxicity
-no reports
40
Roboflavin function
- plays role in energy metabolism of all cells
| - helps to support vision and skin health
41
Riboflavin food srouces
-milk products, and enriched grain
42
Riboflavin deficiency
=ariboflavinosis
43
when diet is deficient in _____, it may also be deficient in riboflavin
- thiamin
- they have similar food sources
- riboflavin deficiency often goes undetected bc symptoms of thiamin deficiency more severe
44
riboflavin toxicity
-no reported
45
niacin functions
-also participates in energy metabolism of all cells
46
what aa can be converted to niacin in body
-tryptophan (found in almost all proteins)
47
niacin equivalents
-amount of niacin preseent in food and take into account the niacin that can be created from the tryptophan present in the food
48
niacin sources
-almost all protein containing foods are a source of niacin and tryptophan (only protein of corn limited)
49
Niacin deficiency
= pellagra
50
niacin toxicity
-linked to supplement intake rather than food
=niacin flush
-over time the body adapts to high doses and syptoms resolve, but it is important to monitor for liver damage
51
Niacin as a medication
-physicians may administer large doses as part of treatment to lower blood lipids
52
pantothenic acid and biotin functions
-both play role in energy metabolism
53
pantothenic acid and biotin food sources
-both are found widespread in foods
54
pantothenic acid and biotin deficiencies
-rare
55
vitamin B6
-pyridoxine
56
vit B6 functions
-participates in over 100 reactions in body tissues and plays role in the metabolism of protein and aa's
57
vit B6 food sources
-meats, fish, and poultry
58
vit B6 deficiency
-may be related to incidence of heart disease (more research needed)
59
cit B6 toxicity
large doses from supplements can be dangerous
60
Folate
=folic acid
61
folate functions
- plays important role in cell division
| - cells that divide rapidly are most vulnerable to deficiency
62
those at risk of folate deficiency
- pregnant
- elderly (many meds interfere with absorption; elderly often have lowered food intake)
- alcoholic (decreased absorption and lowe food intake)
- smokers (folate inactivation in lungs occurs, increasing need)
63
what kinds of meds can interfere with folate absorption
-antacids, aspirin, oral contraceptives, and anticonvulsants
64
what is folate deficiency associated with
- neural tube defects
- women of child birthing years advised to consume a 400ug supplement; all white flour, enriched pasta and corn meal have been fortified
65
neural tube defects
-abnormalities of the brain and spinal cord apparent at birth
66
folate food sources
-liver, legumes, beets, leafy green vegetables, as well as oranges, and cantaloupe
67
Vit B12 deficiency
- bc vit B12 and folate closely related, B12 deficiency causes identical anemia to folate deficiency
- also causes neuromuscular dysfunction, such as creeping paralysis and general malfunctioning of nerves and muscles
68
Vit B12 deficiency
- bc vit B12 and folate closely related, B12 deficiency causes identical anemia to folate deficiency
- also causes neuromuscular dysfunction, such as creeping paralysis and general malfunctioning of nerves and muscles
69
will admin of folate clear up anemia
yes
| -but allows vit B12 deficiency (and corresponding NM dysfunction) to continue undetected
70
what does Vit B12 require for absorption
-intrinsic factor (made by stomach)
71
what happens to IF as we age
-as we age, many lose ability to produce enough stomach acidity and IF, which reduces ability to absorb B12
72
does a change in diet always correct Vit B12 deficiency
- no
| - some people have inherited defect in gene for IF (this usually begins in mid-adulthood)
73
B12 food sources
-only present in foods of animal origin (vegetarians and vegans at higher risk; some vegetarian products are fortified- i.e. soy meat alts, some fermented products, some algae, Red Start T6635 yeast)
74
can a vitamin B12 deficiency occur in her infant even if the pregnant/lactating mother appears healthy?
yes
-deficiency in pregnancy can cause irreversible NS damage in the developing fetus, which cannot be detected until the baby is born
75
Vit C
= ascorbic acid
76
vit C fxn
-performs # of functions but best known is maintaining connective tissues and as an antioxidant
77
Vit C deficiency
- scurvy (symptoms from the breakdown of collagen in absence of vit C)
- rare
78
Vit C toxicity
- result of vit C being used as a nutraceutical
- here recommendations as high as 4000mg/day but UL= 2000mg/day
- leads to megadoses
79
nutrceutical
-marketing a nutrient as having pharmacological effect
80
Vic C requirement
-not that much bc much is recycled back into the active form for reuse (and urinate the rest out)
81
Vic C and smokers
-tobacco introduce oxidants to our body that depletes the body's Vit C
-therefore they need more to maintain blood vitamin levels similar to that of a non-smoker
(even being around second hand smoke)
82
Vit C sources
- f+v are key
| - best= fresh, raw and quickly cooked fruits, vegetables and juices
83
what is Vitamin C vulnerable to?
-heat and also destroyed by oxygen
84
Phytochemicals
- compounds derived from plants and have biological activity in the body and may support health beyond traditional nutrients
- can have profound physiological effects on our body
85
what was once thought about phytochemical
-at one time, phytochemical were thought to only play role in sensory qualities in food
86
food contains thousands of ___
chemicals
87
are chemicals in food all good?
some are beneficial, some have no effect, and others are harmful
88
food chemicals in different peple
-they exert different effects on different people or when taking differing doses or at different life stages
89
what is the safest way to obtain phytochemicals
-through foods
(as it is uncertain if any phytochemical is actually effective at fighting disease or if it safe to consime them at high doses)
90
functional foods
-whole or modified foods that demonstrate physiological benefits or have the ability to reduce chronic disease risk due to the phytochemical that they contain
91
modified functional foods
- have phytochemicals, nutrients, or other compounds added to them, which provide additional benefits
- added phytochemicals may produce effects that are vastly different from those seen in whole foods
- ie margarin, juice or yogurt that has plant sterol added to them
92
how do vitamins differ from carbs, fats and proteins
-structure (vits are individual units), function (don't yield energy) and dietary intake (micro or milligrams, not grams)
93
what does bioavilabilty of a vitamin depend on?
- efficienct of digestion and time of transit through GI
- previous nutrient intake and nutrition status
- other foods consumed at the same time
- method of food prep
- source of nutrient
