chapter 8 vitamins Flashcards
a vitamin is a
complex organic compound that regulates certain metabolic process in the body
a vitamin meets the following criteria
- the body cannot synthesize the compound or make enough to maintain good health
- it occurs naturally in commonly eaten foods
- signs and symptoms of a health problem eventually occur when the substance is missing from the diet
- good health is restored if the deficiency disorder is treated early by supplying the missing substance
it is ___ that any vitamins still need to be discovered
unlikely
why is it unlikely that any vitamins still need to be discovered
babies grow and thrive on infant formulas
very ill people who cannot eat solid foods can be kept alive for years on liquid synthetic feedings that contain all known nutrients
if a vitamin remained undiscovered, infants and people who are unable to consume solid foods would not be able to survive on formula diets
the body requires vitamins in ___ or ___ amounts
milligram, microgram
bone health vitamins
a, d, k, c
energy metabolism vitamins
thiamin, riboflavin, niacin, pantothenic acid, biotin, b-12, b-6
blood clotting vitamin
k
amino acid metabolism vitamins
b-6, folate, b-12, c, choline
antioxidant defense vitamins
e, c, carotenoids
immune function vitamins
a, c, d, e
RBC formation vitamins
b-6, b-12, folate, riboflavin
growth and development vitamins
a, d, choline
monosaccharides vitamin energy metabolism
thiamin, pantothenic acid, niacin, biotin
fatty acids and glycerol vitamin energy metabolism
all B except b-6
amino acid vitamin energy metabolism
b-6, b-12, biotin, folate
vitamins for intermediate energy-yielding compounds
riboflavin, niacin, folate, b-12
oxidizing agent
substance that removes electrons from atoms or molecules
oxidation reactions can form
unstable substances: radicals
most radicals are
highly reactive
why are radicals highly reactive
unpaired electron
radicals can remove
electrons from more stable molecules
radical damage may contribute to
serious chronic diseases and the aging process
radical formation:
1. a radical acts as an ___ by ____
arrow, hitting a vulnerable molecule, such as DNA
radical formation:
2. the damaged molecule becomes the source of
another radical that strikes another vulnerable molecule
radical formation:
3. the reaction repeats itself as
another radical forms and attacks another vulnerable molecule
antioxidant
substance that gives up to electrons to radicals
by _____, antioxidants stabilize the radical and help protect other molecules
giving up an electron
sources of vitamins
occur naturally in foods, synthesized in a lab
biological activity
vitamins degree of potency or effects in the body
some vitamins are more biologically active in the
natural form or synthetic form
bacteria in the large intestine can produce certain vitamins
biotin, K
the body is able to synthesize
vit d, niacin
vitamin enrichment
addition of specific amounts of thiamin, riboflavin, niacin, folic acid, and iron to refined wheat flour and other milled grain products
vitamin fortification
addition of one or more nutrients to a wide array of commonly eaten processed foods during manufacturing
fat soluble vitamins
a, d, e, k
water soluble vitamins
B group, c, choline
____ vitamins are generally more readily stored in the body and have a higher risk of developing toxicity
fat soluble
most vitamins are absorbed in the
small intestine
fat soluble vitamins are absorbed with
dietary fat
absorption generally increases when the body needs more of the vitamin during
periods of growth
pregnancy, breastfeeding
_____ that affect the GI tract can reduce vitamin absorption
disease, conditions
cystic fibrosis interferes with ___ digestion and ___ soluble vitamin absorption
fat, fat,
vitamin deficiencies can result from
poor diets or certain health conditions
in the US severe vitamin deficiencies are uncommon due to
food preservation, food enrichment or fortification, availability of fruit or veggies
populations at risk for vitamin deficiency
alcohol use disorders, older adults, people who are hospitalized for lengthy periods, people with anorexia nervosa and certain GI tract disorders and rare metabolic defects
vitamin toxicity can occur from
supplements, megadoses
preserving the vitamin content of food
- avoid buying wilted, bruised, shriveled, moldy produce
- eat fresh produce with edible peels or skins
- trim, peel, cut raw produce just before eating or serving
- cook in small amounts of water and reuse cooking water
- cut food into larger pieces for cooking
- use quick cooking methods such as microwaving, steaming, stir frying
MyPlate includes vitamins
a, d, e, k
MyPlate: oil vitamins
e, d, a, k
MyPlate: fruit vitamins
a precursors, e
MyPlate vegetable vitamins
a precursors, k, e
my plate dairy vitamins
a, d
my plate grain vitamins
e
my plate protein vitamins
e, a, d,
vitamin a major functions in the body
normal vision and reproduction, cellular growth, immune system function
vitamin a adult RDA/AI
700-900 mcg
vitamin A major dietary sources
preformed: liver, milk, fortified cereals
provitamin: yellow-orange, red, dark green fruits and vegetables
vitamin a major deficiency signs and symptoms
night blindness, xerophthalmia, poor growth, dry skin, reduced immune system functioning
vitamin a major toxicity signs and symptoms
nausea vomitting, headaches, bone pain and fractures, hair loss, liver damage, interference with vitamin k absorption
vit a UL
3000 mcg/day
vitamin d major functions
absorption of calcium and phosphorus, maintenance of normal blood calcium, calcification of bone, maintenance of immune function
vit d RDA
15-20 mcg
vit d major dietary sources
vit d fortified milk, fortified cereals, fish liver oils, fatty fish
vit d major deficiency signs and symptoms
rickets in children, osteomalacia in adults, soft bones, depressed growth, reduced immune system functioning
vit d UL
100mcg/day
vit d major toxicity signs and symptoms
poor growth, calcium deposits in soft tissue
vitamin e major functions
antioxidant, maintenance of nervous and immune system functions
vitamin e RDA
15mg
vitamin e major dietary sources
vegetable oils, certain fruits and vegetables, nuts and seeds, fortified cereals
vitamin e major deficiency signs and symptoms
loss of muscular coordination, nerve damage, reduced immune system function
vitamin e UL
1000mg
vitamin e toxicity signs and symptoms
excessive bleeding
vitamin k major functions
production of active blood-clotting factors
vitamin k RDA
90-120 mcg
vitamin k major dietary sources
green leafy veggies, canola and soybean oils
vitamin k deficiency signs and symptoms
excessive bleeding
vitamin k UL
unknown
vitamin k toxicity signs and symptoms
unknown
vitamin a animal sources
retinol (preformed)
liver, fish liver oils, butter, eggs, fortified milk
most active form of vitamin a in the body
retinol
vitamin a plant sources
carotenoids (provitamin)
yellow-orange, red, some green fruits and vegetables
some carotenoids, particularly _____, can be converted into active vitamin a
beta-carotene
vitamin a needed for production, maturation, and maintenance of
epithelial cells
nightblindness
inability to see in dim light
rods need vitamin a to form
rhodopsin
vitamin A RDA males and females
900, 700
vitamin a deficiency affects epithelial cells
certain epithelial cells produce too much keratin
vitamin a is a ____ and can cause miscarriage
teratogen
why is vitamin d necessary
increase calcium and phosphorus absorption
reduce urinary calcium excretion
increase calcium and phosphate deposits in bone
proper immune function
production of adequate vitamin d is possible if
you live south of the 33rd parallel and are outdoors when the sunlight is most intense
vitamin of public health concern
d
rickets
vitamin d deficiency disorder in children that results in soft bones that do not grow properly and become deformed
osteomalacia
poorly mineralized bones that break easily
long term vitamin d deficiency contributes to
osteoporosis
vitamin e form used by the body
alpha-tocopherol
vitamin e is destroyed by
exposure to oxygen, metals, lights, and high temperatures
phylloquinone
family of vitamin k, in plants
menaquinone
family of vitamin k, fermented foods
most water soluble vitamins function as components of
specific coenzymes
thiamin functions
part of coenzyme involved in release of energy from carbohydrates
metabolism of certain amino acids
synthesis of neurotransmitters
thiamin food sources
whole grain and enriched breads and cereals, pork, nuts, legumes, OJ
thiamin RDA
1.2 males, 1.1 females
thiamin deficiency
beriberi
beriberi
weakness and poor muscle coordination
wernicke-korsakoff syndrome
degenerative brain disorder resulting from thiamin deficiency that occurs primarily among people with alcohol use disorder
excess thiamin is
readily excreted in urine
riboflavin functions
part of two coenzymes needed for the metabolism of carbs, lipids and amino acids
riboflavin food sources
milk, yogurt, other milk products, enriched cereals, liver
riboflavin RDA
1.1 females 1.3 males
riboflavin deficiency
rare
riboflavin toxicity
not known
niacin functions
part of two coenzymes that participate in numerous chemical reactions, including releasing energy from macronutrients
niacin food sources
enriched cereals, beef liver, tuna, salmon, poultry, pork, mushrooms
the human body can synthesize some niacin from
tryptophan
niacin RDA
14mg female 16mg male
niacin deficiency
pellagra
pellagra
dermatitis, diarrhea, dementia, death
niacin toxicity
not from naturally in foods
megadoses of supplements can cause flushing, itching, GI ulcers, vision loss, liver damage
vitamin b-6 functions
part of coenzyme needed for amino acid metabolism
neurotransmitter synthesis
participates in the synthesis of heme
vitamin b-6 food sources
liver, meat, fish, poultry, potatoes, bananas, spinach, sweet red peppers, broccoli
vitamin b-6 RDA
1.3-1.7mg
vitamin b-6 deficiency
rare
dermatitis, anemia, seizures, depression, confusion
vitamin b-6 toxicity
from megadoses
folate functions
part of coenzyme THF
DNA synthesis, amino acid metabolism
conversion of homocysteine to methionine
folate forms
folate, natural
folic acid, synthetic
folate food sources
green leafy vegetables, liver, legumes, asparagus, broccoli, OJ
folate RDA
400mcg
folate early deficiency
lack of folate affects cells that rapidly divide such as RBD
folate deficiency leads to
megaloblastic anemia
folate deficiency during pregnancy increases the risk of
giving birth to infants with neural tube defects
spina bifida
spine does not form properly before birth and fails to enclose the spinal cord
anencephaly
brain does not form properly or is missing
folate concerts with high intakes
none
vitamin b-12 functions
part of coenzymes needed for
folate metabolism, homocysteine metabolism, maintenance of myelin sheaths
vitamin b-12 food sources
animal foods, fortified foods
vitamin b-12 in food is bound to
proteins
after release from protein, vitamin b-12 must bind to
intrinsic factor for absorption in ileum
vitamin b-12 RDA
2.4 mcg
vitamin b-12 deficiency
characterized by nerve damage and megaloblastic RBC
b-12 deficiency often results from
food-cobalamin malabsorption
food-cobalamin malabsorption
problems that interfere with intestinal absorption of cobalamin
pernicious anemia
autoimmune disorder that causes inflammation and destruction of cells in the stomach that produce intrinsic factor
pantothenic acid functions
component of coenzyme a, energy metabolism and fatty acid production in the body
pantothenic acid food sources
fortified cereals, beef and chicken liver, sunflower seeds, mushrooms, peas, soy milk
biotin functions
chemical reactions that add CO2 to other compounds
biotin food sources
variety of foods, liver, eggs, peanuts, salmon, pork, sunflower seeds, mushrooms
avidin
protein in raw egg whites that binds biotin and prevents its digestion
vitamin c functions
collagen synthesis and maintenance
antioxidant activity
immune system functioning
synthesis of bile, certain neurotransmitters, hormones
collagen
protein that gives strength to connective tissue such as bone, cartilage, and tendons
vitamin c also called
ascorbic acid
vitamin c food sources
fruits and vegetables
scurvy
vit c deficiency
fatigue, petechiae, poor wound healing, east bruising, bleeding gums, loosened teeth
vitamin C RDA
75 female 90 male
people who smoke need to add an extra ____ mg of vit c per day
35
vitamin c excess intake
gastrointestinal upset
vitamin-like nutrient
choline
choline sources
liver, wheat germ, eggs, beef, pork
choline functions
needed for the production of phospholipids and neurotransmitter acetylcholine
choline AI
425 female 550 male
choline deficiency
liver damage
choline excessive intake
fishy body odor, reduced BP
niacin as medicine
megadoses have been prescribed to reduce LDL cholesterol levels
natural vitamins are better for you because they have more biological activity than synthetic vitamins. true or false
false
certain vitamins can be toxic if consumed in high doses. true or false
true
vitamin e is an antioxidant. true or false
true
vitamins are a source of “quick” energy. true or false
false
according to scientific research, taking large doses of vitamin c daily prevents the common cold. true or false
false
