Exam 2: Water-Soluble Vitamins Flashcards
Vitamin C functional form
Ascorbic acid
Vitamin C is nonessential for
Most animals and plants (made from glucose and galactose)
Vitamin C IS essential for
Humans, primates, fruit bats, guinea pigs and some birds
Vitamin C function in connective tissue
- Required for collagen synthesis
- necessary for hydroxylation of proline and lysine
Vitamin C is a coenzyme for
More metabolically active tissues (adrenals, brain, liver, pancreas)
Vit C is required for conversion of _____ to _____, synthesis of _______, metabolism of ________ and absorption of ________
Dopamine to norepinephrine, synthesis of carnitine, metabolism of folate and tryptophan, absorbs non-heme iron
Vitamin C acts as an____ and can regenerate
Antioxidant, regenerate vitamin E
Can donate 2 hydrogens
Proline to Hydroxyproline requires
Vitamin C and iron via proline hydroxylase
Lysine to hydroylysine requires
Vitamin C and iron via lysyl hydroxylase
RDA for Vitamin C
Men= 90 mg Women= 75 mg Smokers= RDA + 35 mg
Smokers require more vitamin C because of
Free radicals
Characteristics of Vitamin C deficiency
Easy bruising Pinpoint Hemorrhages Bone fracture Poor wound healing Bleeding gums Tooth loss Scurvy
4 Hs of Scurvy
Hemorrhagic signs (poor wound healing)
Hyperkeratosis of hair follicles
Hypochondriasis (psychological)
Hematologic (impaired collagen synthesis and decreased iron absorption)
Scurvy can be found in people with
Poor diet, alcoholism, or drug habits
Must consume ______ vitamin C to prevent scurvy
10 mg/ day
Sources of vitamin C
- Bell peppers
- Citrus fruits and fruit juices
- Broccoli
- Dark green leafy veggies
Vitamin C is unstable due to
Oxygen, heat, and basic pH (baking soda destroys)
Cooking effects on vitamin C
- easily extracted in water
- prepared veggies refrigerated for 24 hours has lost about 50% of the vitamin C
- Frozen often contains more vit C than fresh
Thiamin functions
Coenzyme (TDP or TPP)
Noncoenzyme (TTP)
Thiamin as a coenzyme
- energy production (used by dehydrogenase)
- NADPH and pentode synthesis (part of transketolase)
Thiamin functions as a noncoenzyme in
Nervous system
- regulates sodium channels and chloride transport in nerve transduction
Thiamin requirements
Men- 1.2 mg
Women- 1.1 mg
Organs target by thiamin deficiency
Peripheral nerves, heart and brain
Thiamin sources
Yeast Pork Whole grains Enriched grains Legumes
Thiamin deficiency in nerves, heart, and the brain causes
In Peripheral nerves- numbing and paralysis
Heart- edema and fatigue
Brain- decreased alertness
Chronic thiamin deficient is called
Beriberi
Populations where beriberi is common
Where diet mostly consists of polished rice
Dry Beriberi
- low thiamin and high carb intake
- muscle weakness, extremity wasting, peripheral neuropathy, tender calf muscles
Wet beriberi
- enlarged heart, rapid heart beat, peripheral edema, high BP
Acute beriberi
- chronic infant deficiency (2-5 months)
- breastfed by mothers with poor thiamin intake
- anorexia, nausea, vomiting, lactic acidosis
Chronic thiamin deficiency in alcoholics
Wernicke- Korsakoff Syndrome
Chronic thiamin deficiency in alcoholics results in
Decreased thiamin intake
Decreased thiamin absorption
Increased thiamin utilization
Most common nutritional deficiency in alcoholics
Thiamin
TUL of thiamin
None
Raw seafood contains ______ which
Thiaminases; degrades thiamin… bad source
Which disorder is only due to a dietary deficiency of thiamin
Acute beriberi
Dry beriberi consists of low thiamin intake and
High carbohydrate intake; therefore need to eat more thiamin
Symptoms of Wernicke- Korsakoff syndrome
Psychosis/ delirium
ataxia of gait and stance, anorexia
Vomiting
Enlarged heart
Thiamin toxicity is rare but problems could be caused when:
100X the RDA is given by IV
-causes headache, convulsions, cardiac arrhythmia, anaphylactic shock
Thiamin instability is caused by
Neutral or basic pH that occurs in water during cooking
Riboflavin coenzymes
FAD and FMN
FAD and FMN coenzyme functions
- Flavin ring important for redox reactions
- Found in ETS for dehydrogenases and 1st step in beta-oxidation and Krebs
- Synthesis of niacin, folate, and B6
- Converts retinal to retinoic acid
Requirements of riboflavin
Men= 1.3 mg Women= 1.1 mg
Riboflavin Deficiency happens after
Several months of deficient intake
Riboflavin deficiency causes
Photophobia
Burning and itching eyes
Soreness of mouth (cheilosis, angular stomatitis, glossitis & magenta tongue)
Severe riboflavin deficiency inhibits
Vitamin B6 and NAD synthesis
*B vitamin deficiencies can have similar signs
Magenta tongue differentiates
Ariboflavinosis vs any other b vitamin deficiency
Riboflavin deficiency causes
Ariboflavinosis
400 mg of riboflavin can help treat
Migraines with no side effects
Riboflavin sources
- cow’s milk
- enriched grains
- almonds
- soybeans
- eggs
- meats
Riboflavin instability is caused by
Light and water during cooking
Niacin coenzymes
NAD and NADP
NAD and NADP are coenzymes for >200 enzymes that are mostly
Dehydrogenases
Most common nutritional deficiency in alcoholics
Thiamin
Vit C is required for what posttranslational modification in collagen synthesis?
Hydroxylation q
A male smoker should consume how much vitamin C daily?
125 mg
110- female smoker
Which is NOT one of the 4 H’s of scurvy?
- Hyperkeratosis
- Hypertension
- Hematologic
- Hypochondriasis
- Hypertension
T/F there is no tolerable upper intake level set for vit. C?
False
TTP is used in
Na+/Cl- transport
A good source of thiamin
Grilled pork chops
Disorder due to a dietary deficiency only
Dry Beriberi
Dry beriberi causes
Tense calf muscles
Symptoms seen with Ariboflavinosis near the mouth
Cheilosis
Angular stomatitis
Glossitis and MAGENTA TONGUE
Other Ariboflavinosis symptoms
Photophobia and corneal vascularization
Seborrheic dermatitis
Anemia
Peripheral neuropathy
NAD and NADPH function as _ ______ in redox reactions
H acceptors
NAD
Used in glycolysis, Krebs cycle, beta oxidation, and ethanol metabolism
NADPH
Used in fatty acid synthesis, cholesterol synthesis, and folate synthesis
Most of our niacin comes from
Tryptophan
60 mg tryptophan =
1 mg niacin
Pellagra was discovered by
Dr. Joseph Goldberger
3 D’s of Pellagra
Dermatitis
Dementia
Diarrhea
*DEATH
Dermatitis associated with pellagra looks like a _____ on face, neck, and extremities
Sunburn.
Dementia symptoms associated with Pellagra
Headache, memory loss, confusion, disorientation
Diarrhea is caused during Pellagra because of
Digestive abnormalities causing inflammation of mucus membrane of mouth and GI tract (glossitis, cheilosis, angular stomatitis)
Pellagra is caused by a _____ or _______ deficiency
Niacin or tryptophan
Pellagra is common where ______ is a staple in the diet
Corn
Pellagra is often found with ________
Ariboflavinosis
Having Ariboflavinosis causes Pellagra because you make niacin from tryptophan and tryptophan needs riboflavin
Niacin Toxicity
- No toxicity from dietary sources
- Gram doses can lower Triglycerides and LDL and raise HDL
Side effects of using Nicotinic Acid to lower TGs and LDL and raise HDL
Vasodilation (flushing from histamine), heartburn, liver damage, gout, impaired blood glucose