chapter 8 Flashcards
provitamins
- substance converted to a vitamin in an organism
- precursor to vitamin
examples of provitamins
- tryptophan: amino acid converted to niacin
- beta carotene: converted to vita
water soluble vitamins
- less chance of harm than fat soluble
- not retained by body
- need regular consumptio
- quick deficiencies
Thiamin functions
- coenzyme in energy metabolism
- helps synthesize neurotransmitters
food sources of thiamin
- whole and enriched grains
- pork, legumes, nuts, liver
thiamin deficiency
- beriberi
- common with staple diet of white rice
- muscle weakness, anorexia, nerve degeneration, edema
- diagnose using urinary excertion <100ug/day insufficient, <40ug/day extremely low
suspected thiamin deficiency?
- behavioural changes
- eye signs
- gait disturbances
- delirium
- encephalopathy
- patients with poor nutrition
- on insulin for hyperglycemia
- 80% of alcoholics
- elderly
chronic gi problems - anorexia,
- cancer treatment
- diuretic therapy
riboflavin funcitons
- coenzyme in energy metabolism
supports antioxidants
food sources of riboflavin
- milk and dairy products
- whole and enriched grains
riboflavin deficiency
- ariboflavinosis
- common cause: alcoholism and barbituates
- symptoms: mouth sores then anemia
- leads to b6 deficiency
niacin functions
- coenxyme in energy metabolism
- supports fatty acid synthesis
niacin food sources
- whole and enriched grains
- meat poultry fish nuts peanuts
- 1/2 of supply made from tryptophan - high in high quality protein and soy
niacin deficiency
- occurs due to too little trp in diet, high corn diet, low protein diet
- pellagra
- symptoms: dermatitis, diarrhea, dementia, death
niacin toxicity
- high doses used to treat high blood trigs and cholesterol
- raised HDL levels
- side effects: skin flushing, liver damage
b6 functions
- coenzyme in protein and amino acid metabolism
- supports immune system
- normal brain developemnt
- serotonin production
b6 food sources
- whole grains
- lost during refinement and irreplaceable during enrichment
- meat fish poultry liver potatoes bananas sunflower seeds
b6 deficiency
- alcholism
- micryhypochromic anemia
b6 toxicity
can cause permanent nerve damage in high doses
folate food sources
- leafy greens, orange juice, legumes fortified cereals enriched grains
folate functions
- coenzyme in DNA synthesis and cell division
- needed for normal red blood cell synthesis
folic acid
- synthetic form of folate
- supplements
- added to fortified foods
folate deficiency
- can contribute to neural tube defects
- women of child bearing age need 400ug per day of folic acid
- too late once pregnancy suspected
b12 functions
- normal folate function
- DNA and red blood cell synthesis
- maintains myelin sheath around nerves
b12 food sources -
- meat liver milk eggs
- supplements or fortified foods
b12 deficiency
- begaloblastic anemia
- nerve damage
b6 b12 folate and homocysteine
- low amounts of those vitamins associated with homocysteine
- homocysteine marker for heart disease
- higher levels: thickens artery walls and promotes blood clots
- recommended to get enough vitamins
vitamin c functions
- collagen synthesis
vitamin c food sources
- fruits: citrus, strawberries, kiwi
veg: broccoli, tomatoes, potato skin
vitc toxicity
- may cause GI distress in high doses
vit c deficiency
scurvy
unravels triple helix of collagen
fat soluble vitamins
- vits A D E K
- require bile and dietary fat
- once absorbed, transported through lymphatic system in chylomicrons before entering blood
- stored in body fat
- intakes vary without risk of deficiency
- not easily excreted
- can accumulate - risk of toxicity in hgih levels
vit d synthesis
- pre d molecule in skin stimulated by specific uvb wavelength
- activated in liver and kidney
vit d food sources
- milk, dairy products made from fortified milk
- margaine
- fatty fish, egg yolk
vit d3: cholecalciferol
- animal sources
- added to milk
- more expensive to supplement
- more effective at raising levels
vit d2: ergocalciferol
- plant sources
- added to soy milk
- inexpensive to supplement
vit d functions
- bone health: allows calcium to leave intestine and enter bloodstream and remain in bone, also works kidneys to help reabsorb calcium that would otherwise be excreted
- vit d receptors in most tissue
- muscle health
- neurological health
- immune function
latitude effect on vit d
- we are too north to get enough vit d from sun
vit d deficiency
- dark skinned poeple need more sun
- rickets in children: most cases in intermediate to dark skinned infants or toddlers who were exclusively breast fed without vit d supplements
- when deficient calcium cant be absorbed efficiently and can have improper bone mineralization
- can lead to osteomalacia
vit d toxicity
- hgih blood urine calcium concentrations, depositing of calcium in blood vessels and kidneys, cardiovascular damage, death
rickets in the north
- 1999-2013 rickets in alaskan indigenous childre in creased 2.3 fold for every 4 degree increase in latitude
vit E functions
- antioxidant: protects cell membranes from free radicles
- short lived, highly reacitve chemicals that can have negative effects on cells DA and membranes
forms of vit e
- tocopherol: alpha, beta, gamma, delta
- tocotrienol: delta, alpha, beta, gamma
vit e food sources
- wheat germ/oil
- nuts and seeds
- vegetable oils, margarine, salad dressing
vit e deficiency
- due to fat malabsorption disorders
- hemolysis
vit e toxicity
- rare
vit k functions
- blood clotting
- formation of bone
intrinsic sources of vit k
- made by bacteria in intestinal tract
food sources of vit k
- cabbage broccoli spinach leafy greens cereal soybeans
vit k deficiency
- rare
- increases risk of hemmorhage
vit k toxicity
- can interfere with anticoagulant medications
vit a functions
- vision, cell development and health, immunity
vit a sources
- preformed from animal prdocuts or supplements (retinoids) - liver, milk, egg yolk
- precursor from from plant foods (carotenoids) - yellow/orange fruits and veg
chemical forms of vit a
- retinol: most active form, stored in liver
- retinal
- retinoic acid
vit a deficiency
- affects eyes, skin, other epithelial tissues
- can be due to some diseases
- vision abnormalities and night blindness
vit a toxicity
- preformed can be toxic in high amounts
- medications made from vit a can have side effects
functional foods
- provide health benefits beyond basic nutrition
phytochemicals
health promoting substances in plant foods
zoochamicals
health promoting substances in animal foods
phytochemicals in modern diet
- carotenoids
- flavonoids
- indoles and alliums
- phytoestrogens and other plant hormones
carotenoids
- yellow, orange, red pigment plants
- might boost immune function
- powerful antioxidants - scavenge free radical sin body
lycopene
- pigment that colours tomatoes, watermelon, grapefruit, gauva
- autumn olive berry: 17x lycopene of a tomato, may reduce risk of cancer, heart disease, plant sold in nurseries as berry producer for birds
lutein and zeaxanthin
- identical chemical formulas - isomers
- component of central region of retina and may play a role in visual acuity
- may reduce risk for age related macular degeneration
- kale, other leafy greens
age related macular degeneration
- leading cause of vision loss in people over 55
