Chapter 7 - Vitamins (Day 1 - 11.5.15) Flashcards
vitamin (defined)
“essential” nutrients; organic compounds; needed in small amounts
water-soluble vitamins
vitamins B and C
fat-soluble vitamins
vitamins A, D, E, and K
solubility of vitamins determines how they are… (4 actions)
absorbed, transported, excreted, and stored in the body
where are vitamins found?
in ALL food groups, including oils
which food groups lack B12?
grains, fruits, and vegetables
which food groups lack vitamin C?
grains, dairy, and protein
what is another source of vitamins?
vitamin fortification
examples of government mandated vitamin fortification
B vitamins and iron added to grains; vitamin D added to milk
why fortify foods?
prevent nutrient deficiencies and promote health
concern with voluntary fortification (not government mandated)
risk for exceeding ULs –> adverse health effects and nutrient toxicities
what can cause nutrient losses in foods when they are processed, prepared, and stored? (7 variables)
heat, light, oxygen, passage of time, food processing, cooking, storage
fresh vs canned vs frozen
fresh- less nutrients b/c travels in trucks, in stores, on shelves, then sits in fridge
canned- high temps used in canning reduce nutrient content, but are cheaper and last longer
frozen- often frozen in the field to minimize nutrient loss –> may supply more vitamins than fresh
what helps release vitamins from food ( 2 actions)
mechanical digestion in the mouth (“chewing”), and chemical digestion in the stomach (some) but more in the small intestine (pancreatic digestion enzymes)
where does vitamin absorption occur?
mainly in the small intestine, but a small amount of niacin is absorbed in the stomach
how do some water-soluble vitamins get absorbed? (2 ways)
transport system (energy needed) OR they bind to a specific molecule
what happens after water soluble vitamins are absorbed?
they are able to go directly into the bloodstream with most being bound to blood proteins for transport to the cell
micelle
a particle that is formed in the small intestine when the products of fat digestion are surrounded by bile
composition of micelle
free fatty acids, glycerol, monoglycerides, cholesterol, phospholipids, and fat-soluble vitamins surrounded by bile
purpose of micelle
facilitates the absorption of fats and fat soluble vitamins
chylomicrons
a lipoprotein comprised id newly reassembled TGs, cholesterol, fat-soluble vitamins that are packaged with phospholipids and protein
purpose of chylomicrons
transport fats and fat soluble vitamins out of mucosal cells
how do chylomicrons leave the mucosal cells? why this route?
leave via the lymph –> blood stream –> deliver TGs to cells in the body b/c too big
large intestine
bacteria can make a small amount of some vitamins, some of which are absorbed
bioavailability
extent to which the body can absorb and use a nutrient
vitamin bioavailability is influenced by the following (3 variables)
composition of the diet, condition of the GI tract, overall health of the body
examples of impaired absorption
diet very low in fat –> impair fat-soluble vitamin absorption
low concentrations of blood proteins –> impair water-soluble vitamin absorption
provitamin/vitamin precursor
compound in its inactive form that is converted to active form once in the body
coenzyme
organic non-protein substance that binds to an enzyme to promote the activity of the enzyme with which it is bound
enzymes that require coenzymes are…
considered incomplete; binding of coenzyme –> “active” enzyme
ALL of WHICH type of vitamin acts as coenzymes (NEED TO KNOW)
B vitamin
antioxidant
substance that decreases the adverse effects of reactive molecules on normal physiological function. they protect against oxidative damage
oxidative damage
damage caused by highly reactive oxygen molecules that steal electrons from other compounds, causing changes in structure and function
free radical
type of highly reactive atom or molecule that causes oxidative damage
what is the significance of antioxidants donating electrons?
the electrons stabilize the free radical, causing it to no longer be “reactive”
which vitamins are antioxidants? (3 vitamins)
vitamin C, vitamin E, and provitamin A
vitamin content on food labels
- currently required to list amounts of vitamin A and vitamin C as a % DV
- if proposal goes through, those two will be replaced with vitamin D and Potassium
what is considered an “excellent source” for vitamins
20% or more of DV
what is considered a “good source” for vitamins
between 10% and 19% of DV
what is considered a “poor source” for vitamins
5% or less of DV
general water-soluble vitamin (vitamins B&C) info
- easily absorbed
- not stored in the body to any large extent –> excess is excreted in the urine
- they have to be consumed regularly
- toxicity is not an issue if they are obtained from foods, but toxic levels can occur with supplementation
B vitamins
Thiamin, Riboflavin, Niacin, Folate, B6, B12, Biotin, Pantothenic acid
Tender Romance Never Fails with 6 or 12 Beautiful Pearls
every B vitamin is part of what???
ONE OR MORE COENZYMES
B vitamins are directly involved with transferring the blank from CHO, fat, and protein to blank
energy; ATP
what do B vitamins NOT provide us with?
energy
a deficiency of ANY B vitamin would…
effect EVERY cell in the body
thiamin
part of a coenzyme needed in energy metabolism
thiamin helps provide energy by aiding in the breakdown of…
glucose
thiamin is needed to convert pyruvate to…
Acetyl Co-A (ACoA)
how thiamin aids nerve function
thiamin occupies a specific site on nerve cell membranes; hence, it is available to breakdown any needed glucose, which is the energy source for nerve cells
thiamin is needed for the synthesis of…
neurotransmitters
thiamin is needed in the metabolism of…(2 answers)
other sugars and certain amino acids
thiamin is required for the synthesis of…(2 sugars)
ribose and deoxyribose
Beriberi (NEED TO KNOW)
thiamin deficiency disease –> marked by inflammatory or degenerative changes of the nerves, digestive system, and the heart. without thiamin, glucose can’t be used normally, nerve impulses cannot be transmitted normally
symptoms of Beriberi
loss of sensation in the hands and feet; edema; muscle weakness and poor coordination; advancing paralysis; poor short-term memory and confusion; and changes to the heart (enlargement and possibly heart failure)
riboflavin
a part of two coenzymes; acts as an electron carrier functioning in reactions needed to produce ATP from CHO, fat, and protein
involved (directly or indirectly) with converting some vitamins into which form? (examples: folate, niacin, B6, and vitamin K)
their active form
occurrence of riboflavin deficiencies
rarely occur, but when it does, it is usually in conjunction with another vitamin B deficiency
symptoms of riboflavin deficiency (4 symptoms)
- cheilosis - cracking and redness of the lips and corners of the mouth
- flaking of the skin around the nose, eyebrows and earlobes
- glossitis - inflammation of the tongue (red&swollen)
- the eyes are affected - increased sensitivity to light; burning; tearing; and itching of eyes
niacin
a part of two coenzymes that are involved in metabolism of glucose, fat, and alcohol as well as the synthesis of fatty acids and cholesterol
niacin can be made in the body from…
tryptophan, an essential amino acid
niacin equivalents (NE)
a measure that accounts for the availability of tryptophan
where is tryptophan abundant?
in most proteins. diet sufficient in high quality protein –> lots of niacin
Pellagra (NEED TO KNOW)
a niacin deficiency disease –> early symptoms are fatigue, decreased appetite, and indigestion
symptoms of Pellagra (4 D’s)
diarrhea, dermatitis, dementia, death
who is at risk of developing pellagra?
poorly nourished and alcoholics
toxicity of niacin –> niacin flush
tingling, burning, and itching sensation of the skin caused by dilation of capillaries under the skin
