Vitamin C/Thiamin Flashcards
T/F
Water soluble vitamins aren’t appreciably diminished when cooking with water?
False,
They are substantially lost during cooking.
How are dietary water soluble vitamins absorbed?
Facilitated diffusion
How are water soluble vitamins absorbed when they are taken as supplements?
Passive diffusion
T/F
Very little water soluble vitamins are stored
True
T/F
Water soluble vitamins are nonessential inorganic molecules
False,
They are essential organic molecules
What 3 major functions are B-complex vitamins for?
Energy releasing
Hematopoietic
Other
What B-vitamins fall under the functional category of energy releasing?
Thiamin, riboflavin, niacin, pantothenic acid, biotin, B6
What B-vitamins fall under the functional category of hematopoietic?
Folate, B12, B6, pantothenic acid
What B-vitamins fall under the functional category of “other”
B6, B12, thiamin, folate, niacin.
T/F
Vitmain C is nonessential for most animals and plants
True
Why is vitmain C nonessential for most animals and plants?
Made from glucose and galactose
What is the oxidized from of ascorbic acid?
Dehydroascorbic acid
Who is Vitamin C essential for?
Humans, primates, fruit bats, guinea pigs.
How does vitamin C act like an antioxidant?
Donates a H to free radicals
Regenerates vitamin E in cells
How does vitmain C act like a coenzyme?
Coenzyme for iron and copper-containing enzymes involved in hydroxylation to form collagen
E.g proline -> hydroxyproline
Lysine -> hydroxylysine.
How does vitamin C affect iron absorption?
Nonheme iron absorption. Ascorbic acid enhaces absorption of iron from plants and supplements
What is the RDA for Vitamin C in men and women respectively?
Men = 90 mg Women = 75 mg
What is the RDA for vitamin C in smokers?
RDA + 35
What are some sources of vitamin C?
Peppers
Citrus fruits & juices
Broccoli
Dark green leafy veggies
T/F
Often times frozen F and V contain more vitamin C than fresh that has been shipped a far distance
True
How much vitamin C is lost in prepared veggies that have been refrigerated for 24 hrs?
50%
What are 2 commonly associated symptoms of scurvy?
Corkscrew hairs
Bleeding gums
How common is vitmain C deficiency and who is it found in?
Rare.
May be found in people with poor diet, alcoholism or drug habits.
What are the 4 signs of scruvy?
Hemorrhagic sings (poor wound healing
Hyperkaratosis of hair follicles
Hypochondriasis (psychological manifestations)
Hemtologic (from impaired collagen synthesis and decreased iron absortion)
What is the tolerable upper intake limit for vitamin C
2g
What can unabsorbed vitamin C cause?
Diarrhea from LI fermentation
What two conditions is there caution for high doses for vitamin C
Kidney disease - increased risk of kidney stones
Impaired iron metabolism - iron toxicity
Thiamin is AKA?
B1. Thiamin pyrophosphate
What are Thiamins coenzyme functions?
Energy production (pyruvate to acetyl CoA). - Used by dehydrogenases
NADPH and pentose syntehsis - part of transketolase
What are Thiamin’s noncoenzyme (TTP) functions?
Nervous system
Regulates sodium channels and chloride transport in nerve transduction
What B-vitamin is PLP (Kreb’s cycle) controlled by?
Vitamin B6
What B-vitamin controlls TDP and transketolate (Krebs cycle)
Thiamin
What B-vitmain controlls NAD/NADP (krebs cycle)
Niacin
What B-vitamin controls FAD (krebs cycle)
Riboflavin
What B-vitamin controls CoA (Krebs cycle)
Pantothenic acid
What is the RDA for Thiamin?
Men = 1.2 mg Women = 1.1 mg
What are some sources for Thiamin?
Pork
Whole grains
Enriched flour
Dried beans
What 4 things destroy Thiamin?
Heat (cooking)
Oxidation
Light
Sulfites
Where are thiaminases found?
Fish and Shellfish
What are the 3 major targets of thiamin deficiency?
Peripheral nerves, heart, brain
What are some signs of early thiamin deficiency?
Anorexia, weight loss, malaise, tender claf muscles, leg numbness, increased pulse rate and palpitations
What symptoms are associated with Wernicke-Korsakoff syndrome (thiamin deficiency)
Alcoholics
Psychosis, delirium, ataxia of gait and stance
What is wet beriberi and what are some symptoms?
Chronic adult deficiency
Enlarged heart, rapid heart beat, periheral edema, peripheral neuropathy, tense calf muscles, high blood pressure
What is dry beriberi and what are some symptoms?
Chronic geriatric deficiency
Muscle weakness, extremity wasting, peripheral neuropathy
What is acute beriberi and what are some symptoms
Chronic infant deficiency (2-5 months of age)
Anorexia, vomiting, enlarged heart.
Who is most at risk for thaimin deficiency in the U.S and why?
Elderly (impaired absorption, dietary deficiency
Alcoholics (impaired absorption, dietary deficiency)
Babies (dietary deficiency)
Patients with malabs conditions
What is the tolerable upper intake limit for thiamin?
None
T/F
Although there is no tolerable upper intake limit, thiamin toxicity is relatively common
False,
It’s rare
What are 2 examples of risk for thiamin toxicity
100x RDA given by IV (headache, convulsions, anaphylactic shock)
1000x RDA by mouth (thaimin hydrochloride) suppresses respiratory center leading to death
