Unit 5: Vitamins Flashcards
what are vitamins
- organic, non-caloric, essential nutrients which is assist in body function
intake of which vitamins often fall below dietary threshold (4)
- A
- D
- E
- C
what are the 2 classes of vitamins
- fat soluble
- water soluble
what are fat soluble vitamins
- vitamins that dissolve in lipid
what is required for absorption of fat soluble vitamins
- bile
where are fat soluble vitamins stored (2)
- liver
- fatty tissues
what is a risk with fat soluble vitamins? what indiciation does this have
- can build up to toxic lvls
= use caution with fat soluble vitamin supplements
list 4 types of fat soluble vitamins
- A
- D
- E
- K
describe the absorption of fat soluble vitamins
- absorbed like fats
- first into the lymph, then into the blood
describe the transport & storage of fat soluble vitamins
- travel w protein carriers in watery body fluids
- stored in the liver or fatty tissues
describe the excretion of fat soluble vitamins
- not readily excreted
- tend to build up in tissues
describe the toxicity of fat soluble
- likely from supplements
- occur rarely from foods
describe the requirement of fat soluble vitamins
- needed in periodic doses ( weekly or monthly)
- depends on the extent of body stores
- like fats, they can be retrieved in times of nutritional deficiency
what was the first fat soluble vitamin recognized
A
what are the 3 active forms of vitamin A
- retinol
- retinal
- retinoic acid
what is the fnxn of retinol? where is iit stored?
- stored in liver
- supports reproduction
- converted into the 2 other active forms
what is the fnxn of retinal
- active in vision
what is the fnxn of retinoic acid (3)
- acts as hormone
- regulates cell differentiation
- embryonic growth & development
as needed
what is a provitamin
- a substance that is converted within the body into a vitamin
what is b-carotene
- found in plant based foods
- antioxidant
- a precursor that is converted into active vitamin A in the body
it takes approx __ ug of b-carotene to supply 1 ug of retinol
12
list the functions of vitamin A (6)
- gene expression
- vision
- cell differentiation
- reproduction & growth
- immunity
what is vitamin A’s role in vision
- keeps cornea clear
- participates in light detection in the retina
- make up retinal pigment molecules which absorb the light
without retinal, the eye has issues ____
- adapting to light changes
what specific role does vitamin A have in reproduction & growth
- sperm development
- fetal growth
what much vitamin A does the body store? what does this mean?
~1 year supply of vitamin A
- symptoms of deficiency take over a year to appear
vitamin A deficiency is the leading cause of???
- preventable blindness in children around the world
what other things does vitamin A deficiency cause (3)
- dried out salivary glands
- hinder stomach & intestinal mucus secretion = hindered digestion & absorption
- associated w high keratin production = hardened & dried cornea
what causes vitamin A toxicity
- supplements
- fortified foods (cereals, vitamins)
what does vitamin A toxicity cause (2)
- weakened bones
- risk of hip fracture
describe how easy/hard is it to get vitamin A toxicity
- chronic intake of even small excess of vitamin A
describe vitamin A use in pregnant women
- pregnant women must be cautious
- chronic use at high doses can cause malformations of the fetus
what age group are the most sensitive to vitamin A toxicity
- children
list 7 good sources of vitamin A and beta-cortene
- fortified milk
- carrots
- sweet potatoe
- spinach
- beef liver
- bok choy
- apricots
what is the chemical name for vitamin D
- cholecalciferol
describe the role of UV light in vitamin D
- UV light from the sun converts a cholestrol compound in the human skin into a vitamin D precursor
- the vitamin D precursor is directly absorbed into the blood
- liver & kidneys then finish converting the precursor to active vitamin D
what is an essential nutrient?
- nutrients the body can’t make or make sufficient quantity of
is vitamin D an essential nutrient
- given enough sun, no
what is the fnxn of vitamin D
- hormone
- role in regulating Ca and PO4 = maintain bone integrity
low vitamin D levels may be linked to… (7)
- HTN
- some types of cancer
- type 1 DM
- heart disease
- rheumatoid arthritis
- IBD
- MS
what is the well-established problems of low vitamin D
- impairment of calcium balance & the bones
list 2 diseases that result from vitamin D deficiency
- rickets
- osteomalacia
what are rickets
- failure of the bones to calcify normally
what is osteomalacia
- bone disease in children & adults
what are 2 symptoms of rickets
- bowed legs
- beaded ribs
list risk factors for vitamin D deficiency (5)
- increases w age
- lower intake
- housebound (little UV exposure)
- decreased ability to activate
- low intake of milk or fortified soy beverage
at what point does our need for vitamin D increase
- after the age 50
of all the vitamins, which is the most potentially toxic? why?
- vitamin D
- can cause calcium blood lvls to raise too high causing kidney stones & calcification
what typicaly causes vitamin D toxicity
- supplements
is there a risk of vitamin D toxicity from sunlight?
- no
list some factors that affect the conversion of sunlight (6)
- skin tone
- sunscreen use
- pollution
- clothing
- geograhic location
- time of year
list some food sources of vitamin D (5)
- fortified milk & margarine
- eggs
- butter
- fortified soy beverages
- fatty fish
describe the vitamin D conten in breast milk
- low source of vitamin D
what does the low content of vitamin D in breast milk mean
- supplementation of breast fed infants is recommened
- infant formula is foritifed
a daily vitamin D supplement of ___ is recommended for exclusively breastfed infants, from birth to one year of age
10 ug (400 IU)
what is the active form of vitamin E
- tocopherol
what is the gold standard of vitamin E
alpha-tocopherol
what is the fncn of vitamin E
- antioxidant & one of the body’s main defenders against oxidative damage
where is vitamin E’s antioxidant effect espeically important?
- in RBC where they are exposed to high conc of O2
what can vitamin E protect against?
heart disease
how does vitamin E help protect against heart disease
- may protect low density lipoproteins from ocidation & reduce inflammation
how common is vitamin E deficiency?
- rare
why is vitamin E deficiency rare? (3)
- found in many foods
- body stores enough vitamin E in fatty tissue to last a long time
- the cells recycle their working supply of vitamin E
what are 2 examples of where vitamin E deficiency may occur?
- in premature infants before b4 the transfer of vitamin E from mother to baby
- may also occur in people w extremely low fat dieys
list symptoms of vitamin E deficiency (3)
- hemolysis due to oxidative stress
- loss of muscle coordination & reflexes
- impaired movement, vision, and speech
how common is vitamin E toxicity
- rare
when is vitamin E toxicity likely to occur (2)
from
- supplements
- fortified foods
what can extremely high doses of vitamin E cause
- interfere w clotting action of vit K
- enhance actions of anticoags
list food sources containing vitamin E (5)
- vegetable oils
- fruits & veggies
- fortified cereals/grains
- meats & meat alternatives
- milk products
what destroys vitamin E? what indiciation does this have?
- heat processing & oxidation destroyts vitamin E
= processed, fast foods, and deep fried foods contains little intact vitamin E
= frsh foods are best source
what iare 2 fnxns of vitamin K (2)
- help synthesize proteins that help clot the blood
- synthesize of key bone proteins
what do anticoagulant meds do
- interfere w the action of vitamin K in promoting clotting
list 1 examples of anticoags
- warfarin/coumadin
how common is vitamin K deficiency
- few north american adults experience it
why is vitamin K deficiency less common
- bc vitamin K is synthesized by gut bacteria
describe vitamin K synthesize in newborns
- newborns are born w a sterile intestinal tract = takes weeks for vitamin K producing bacteria to establish themselves
what else can cause vitamin K deficiency
- antibiotics that kill gut microbiome
how do we prevent hemorrhage in newborns
- they are given a dose of vitamin K at birth
when does vitamin K toxicity occur
- only in healthy adults
- rare
what can high levels of vitamin K interfere w
- anticoagulant effectiveness
what are the 2 categories of vitamin K sources
- non-food = intestinal bacteria
- food
list food sources of vitamin K (3)
- dark, leafy green veggies (spinach, collard greens)
- members of cabbage family
- veggie oils
what are the 2 water soluble vitamins
B and C
describe the absorption of water soluble vitamins
- absorbed directly into the blood
describe the trandport & storage of water soluble vitamins
- travel freely in watery fluids
- most are not stored in the body
describe the excretion of water soluble vitamins
- readily excreted in the urine
describe the toxicity of water soluble vitamins
- unlikely
- but possible w high doses from supplements
describe the requirement of water soluble vitamins
- needed frequently (often daily) bc the body dose not store most of them to any extent
what do the B vitamins act a (2)s
- coenzymes
- involved in energy metabolism
in north america, what is often fortified or enriched w B vitamins
- refined grain products
list 7 types of B vitamins
- thiamin
- riboflavin
- niacin
- pantothenic acid & biotin
- vitamin B6
- folate
- B12
what if the fnxn of thiamin (3)
- critical role in energy metabolism of all cells
- occupies a site on nerve cell membranes
= nerve processes & muscles depend heavily on thiamin
list food sources of thiamin (4)
- legumes
- enriched/whole grain cereals
- sunflower seeds
- pork
what is thiamin deficiency called
- beriberi
what is beriberi characterized by (4)
- loss of sensation in the hands & feet
- muscular weakness
- advancing paralysis
- abnormal heart action
what is severe thiamin deficiency called
- wernicke-korsakoff syndrome
who is wernicke-korsakoff seen in
- those who abuse alcohol
why is wernicke-korsakoff often seen in those who abuse alcohol (3)
- displaces food
- impairs absorption of thiamin from the digestive tract
- speeds up its excretion in the urine
describe thiamin toxicity
- no reported symptoms of thiamin toxicity
what is the fnxn of riboflavin (3)
- energy metabolism of all cells
- supports vision & skin health
list food sources of riboflavin (3)
- milk products
- enriched grain products
- if milk free, generous portions of dark leafy greens
who specifically is riboflavin needed in (2)
- pregnant women
- athletes
who have higher metabolic need
what is riboflavin deficiency called
- ariboflavinosis
what can cause riboflavin deficiency
- when the diet is deficient in thiamin, it may also be deficient in riboflavin (bc of similar food sources)
describe symptoms of ariboflavinosis
- often undetected bc the symptoms of thiamin deficiency are more severe
- includes cracks at the corner of the mouth & sore throat
describe riboflavin toxicity
- no reported symptoms
describe the fnxn of niacin
- energy metabolism
what is tryptophan
- an amino acid found in most proteins that is converted into niacin
what are niacin equivalents? what does it take into account?
- the amt of niacin present in food
- takes into account the niacin that can be converted from the tryptophan present in the food
list food sources of niacin
- almost all protein containing foods
what is the only protein that is limited in tryptophan
- corn
what is niacin deficiency called
- pellagra
what causes niacin toxicity
- linked to supplement intake, rather than food
describe symptoms of niacin toxicity
- niacin flush
- over time, the body adapts & symptoms resolve
what is niacin flush
- dilation of surface capillaries & tingling which may be intense
what is one thing that is important to monitor for niacin toxicity
- liver damage
- which can silently occur
describe the use of niacin as a med
- can be used to lower blood lipids
what is the fnxn of pantothenic acid & biotin
- role in energy metabolism & synthesis
list food sources of pantothenic acid & biotin
- widespread in foods
describe deficiency of pantothenic acid & biotin
- rare
what is the fnxn of vitamin B6 (pyridoxine)
- participates in over 100 rxns in body tissues
- role in metabolism of protein, amino acids, fatty acids, carbs
- helps convert common amino acids into rare ones like niacin
list food sources of vitamin B6 (3)
- meats
- fish
- poultry
what is vitamin B6 deficiency r/t an increased incidence of?
- heart disease
list symptoms of vitamin B6 deficiency (6)
- weakness
- depression
- confusion
- irritability
- dermatitis
- anemia
describe vitamin B6 toxicity
- large doses from supplements can be dangerous
= numbness & loss of ability to walk
what is the fnxn of folate (folic acid)
- important role in cell division
which cells are vulnerable to folate deficiency? what does this cause
- cells that divide rapidly
= anemia, GI tract deterioration
who is at risk of folate deficiency (5)
- pregnant women
- adolescents
- elderly
- alcoholics
- smokers
why are pregnant women & adolescents at risk of folate deficiency
- rapid development
why are older adults at risk of folate deficiency
- many meds interact w folate absorption
- may hvae lowered food intake
what are some meds that interact w folate absorption
- antacids
- aspirin
- oral contraceptives
- anticonvulsant meds
what is folate deficiency associated w
- neural tube defects
= abnoramlities of the brain & spinal cord apparent at birth
who is advised to consume synthetic folate from supplements or enriched foods
- pregnant women
list 3 things that are fortified with folate
- white flour
- enriched pasta
- corn meal
what is a concern with folate supplements
- folate can mask vitamin B12 deficiency by resolving the mcrocytic anemia seen in both folate & B12 deficiency
list 8 good sources of folate
- beef liver
- pinto beans
- asparagus
- avacado
- lentils
- spinach
- enriched cereal
- beets
what is the fnxn of vitamin B12 (3)
- required to activate folate to allow it to play its role in cell division
- maintains the myselin sheath around nerve
fibre - coenzyme in energy & amino acid metabolism
what can insufficient vitamin B12 cause
- nerve damage
what is vitamin B12 closely realted to
- folate
what can vitamin B12 defieicny cause (2)
- anemia (similar to folate deficiency)
- ## neuromuscular dysfunction
what are 2 signs of neuromuscular dysfunction
- creeping paralysis
- general malfunctioning of nerves & muscles
what can clear up the anemia r/t vitamin B12 deficiency? what is a con to this
- folate
- but the vitamin B12 deficiency continues undetected
what does vitamin B12 require to be absorped
- an intrinsic factor
what produces the IF required for vitamin B12 absorption
- the stomach
what is anemia due to IF deficiency called
- pernicuous anemia
what can increase people’s risk of pernicuous anemia
- aging
- inherited defects in the gene for IF
how can aging increase the risk of pernicuous anemia
- as we age, many lose their ability to produce enough stomach acid & IF
list food sources of vitamin B12 (2)
- only present in foods of animal origin
- not in foods from plants
who may be at a risk of vitamin B12 deficiency
- vegetarians & vegans may be
how is vitamin B12 deficiency avoided in vegetarians
- foods are fortified with vitamin B12 (soy beverages, soy meat alternatives)
- red star yeast
who can vitamin B12 deficiency cocur in
- can occur in a pregnant or lactating vegan women’s infant
what can a vitamin B12 deficiency during pregnancy cause
- irreversible nervous system damage in the developing fetus
what is the function of vitamin C (2)
- imp for a # of functions in the body
- maintains the CT (helps form collagen)
- antioxidant
describe deficiency of vitamin C
- extremely rare
what are signs of vitamin C deficiency (4)
- gums bleed easily
- capillaries break under the skin = pinpoint hemorrhages
- symptoms of scurvy
- impaired wound healing (due to lack of collagen)
lots more in the notes
what has caused people to take large doses of vitamin C
- reports of using vitamin C as a nutraceutical (a nutrient as having pharmacological effects)
what are some concerns r/t too megadoses of vitamin C (5)
- nausea
- abdominal cramps
- diarrhea
- disruption of anticoag therapies
describe our requirement of vitamin C
- not v much
- bc most of the vitamin C in our body is recycled back into the active form for reuse
at what point does the body’s pool of vitamin C “overflow”? what does this mean?
- at around 100mg/day
= rest is excreted in the urine
what causes decreased vitamin C ? what indication does this have?
- smoking/tobacco
= need more vitamin C to maintain blood vitamin C lvls similar to a non-smoker
how does smoking/tobacco deplete the body’s vitamin C
- by producing oxidants
list food sources of vitamin C
- fruits & veggies are key sources
- sweet red pepper
- brussel sprouts
- grapefruit
- sweet potatoe
- orange juice
- green peppers
- broccoli
- strawberries
- bok choy
what is vitamin C vulnerable to?
- heat
- and is destroyed by O2
what are phytochemical
- compounds derived from plants that have biological activity in the body
- may support health beyond roles of traditional nutrients
what are phytochemical
- compounds derived from plants that have biological activity in the body
- may support health beyond roles of traditional nutrients
what is the most effective & safest source of phytochemicals? why?
- food
- there is insufficient evidence on how safe it is to consume phytochemical in conc doses
list 3 functions of phytochemicals in the body
- antioxidants
- flavonoids
- carotenoids
what is an antioxidant
- compounds that protect other compounds from damaging rxns involving oxygen by themselves reacting w oxygen
what is a carotenoids
- pigments commonly found in plants & animals
- powerful antioxidants
- some have vitamin A activity
what are flavonoids
- common & widespread group of phytochemicals
what are the physiologic effects of flavonoids
- antioxidant
- antiviral
- anticancer
- yellow pigments in foods
what are functional foods
- whole or modified foods that demonstrate physiological benefits
- or have the ability to reduce chronic disease risk due to the phytochemicals they contain
what are modified functional foods
- foods with phytochemicals, nutrients, or other compounds added to them
what is an example of modified functional foods
- foods that have plant sterole added to them for cholestrol reduction
ex. margarine, juices, yogurt
what is the benefit of sterols
- may inhibit cholesterol absorption in the small intestine
= lowers blood cholestrol & lower risk of heart disease
what are plant sterols
- occur naturally in plant based foods
what are some major sources of plant sterols
- veggie oils
- nuts
- cereals
- legumes
how do plant sterols lower cholesterol
- eating up to 3 g of plant sterols per day increase the removal of cholesterol from the body
when are plant sterols considered a food? natural health product?
- food = when plant sterols are placed in a food product that is intended for normal use as part of the diet
- NHP = if taken as a supplement
what kind of foods are plant sterols allowed to be added to
- spreads
- mayo
- margarine
- salad dressing
- yogurt
- veggie and fruit juices
how much plant sterols is allowed to be added to foods
- limited # of foods will be allowed to contain up to 1 g of plant sterols/serving
- 3g can be added without exceeding the upper intake lvl in adults, 1 g for children
can plant sterol enriched foods be used w cholesterol lowering meds
- use together should be done in consultation w your doctor
- if on statin treatment, it may require the dosage to be adjusted
can plant sterol enriched foods be used by pregnant or breastfeeding women & young children under 5 years of age
- considered safe within the guidelines set by Health Canada
- but not recommended for children, breastfeeding, or pregnant women
why arent plant sterol enriched foods recommended for pregnant or breastfeeding women, or children
- bc they have specific dietary needs & lowering blood cholesterol is not normally a priority
