Vitamins part 2 Water soluble Flashcards
thiamine B1 function
- coenzyme for glycolysis, TCA, AA metabolism
- decarboxylation and transketolation reactions
- may alter membrane conductions
thiamin B1 sources
whole grains
enriched grains
lean pork
legumes
thiamin B1 test
erythrocyte transketolase activity
thiamine blood levels
thiamin Deficiency/ toxicity
Beriberi syndrome:
- Dry/ nervous
- Wet/ Cardiac
Wernicke-Korsakoff:
Ocular + Ataxia + Confusion
what type of nervous function is most effected in wernicke-korsakoff?
retentive memory
riboflavin B2 function
- part of 2 coenzymes: FAD and FMN
- oxidation/ reduction reactions in TCA and oxidative phosphorylation
- AA and fatty acid metabolism
- metabolism of vitamin K, folate, b6, niacin
riboflavin b2 is involved in the metabolism of what other vitamins?
vitamin k
folate
pyridoxine b6
niacin b3
riboflavin b2 source
liver, wheat germ
dairy
meats, poultry
leafy greens
riboflavin B2 test
erythrocyte glutathione reductase (EGRAC): increased in deficiency
riboflavin b2 deficiency
oral-ocular-genital system:
- cheilosis: cracked lips
- stomatitis: sores at corner of moth
- increased vascularization of conjunctiva
- scrotal dermatitis
niacin B3 function
- substituent of electron carrying NAD and NADP
- glycolysis, TCA, oxidative phosphorylation, fatty acid synthesis and oxidation
niacin B3 sources
Preformed:
- meat, poultry, fish
- penut butter
- legumes
Precursor: Tryptophan
-milk, eggs
niacin B3 test
serum niacin
urinary excretion of n1 methyl nicotinamide and 2-pyridone
*ratio
niacin B3 deficiency
Pellagra: 4 Ds Dermatitis: symmetric pattern Dementia Diarrhea Death
Niacin B3 toxicity
- nontoxic in doses 3-6 grams / day nicotinic acid
- lower serum LDL
- peripheral vasodilation/ flushing
Less common:
- increased serum uric acid
- glucose intolerance
- liver damage
folate function
- 1 carbon transfers
- homocysteine –> methionine
- methy donor/ epigenetics
folate source
foliage- deep green leaves
broccoli
orange juice
whole grains
folate test
Folate RBC: Chronic Status
Serum Folate: Recent Intake
Folate deficiency
- macrocytic anemia with hypersegmented neutrophils
- increased plasma homocysteine
- neural tube defects
- MTHFR gene indicates increased requirement
pyridoxine b6 function
aa metabolism/ intercomversion
pyridoxine b6 source
animal products
vegetables
whole grains
pyridoxine b6 test
- pyridoxal phosphate
- homocysteine
pyridoxine b6 deficiency
anemia
seizures
glositis
pyridoxine b6 toxicity
+/- depression
- doses >500mg associated with sensory ataxia, impaired position/ vibration sense
- symptoms partially reversed with dc of supplement
cobalamin b12 function
- 1 carbon transfers
- metabolism of odd chain fatty acids
- binds to IF that is secreted by gastric parietal cells
cobalamin b12 absorption
Gastric Parietal: bound to IF --> Distal ilium: cobalamin-IF complex --> Portal Circulation: bound 2 transcobalamin II
cobalamin b12 source
- ONLY IN ANIMAL PRODUCTS
- liver stores 1-10mg: can take years to develop deficiency unless damage to stomach, ileum, pancreas
cobalamin b12 test
serum b12 level
urine or blood methylmelonic acid: increased in b12 deficit
serum homocysteine: increased in b12 deficit
CBC: increased MCV: non specific
cobalamin b12 deficiency
- macrocytic anemia with hyper-segmented neutrophils
- neurologic disturbances: paresthesias, gain problems, depressions
cobalamin b12 corrections
-hemolytic effects reversible but neuro effects irreversible with long standing deficiencies
vitamin c function
- antioxidant/ reducing agent: electron donor
- collagen synthesis
- Reduce Fe3+ –> Fe2+
- norepinephrine synthesis
vitamin c source
fruits/ vegetables broccoli green pepper citrus potatoes
vitamin c tests
leukocyte
plasma ascorbic acid level
vitamin c deficiency
- scurvy
- loss of precursors of catecholamines and vasoactive/ neurotropic substances
- Symptoms: petechiae, bleeding gums, anemia, brusing, painful joints
what is the safe upper limit of vitamin c
2g/day
alcoholics are the highest risk group for what vitamin deficiency?
thiamine b1
also at risk:
- re-feeding: body stores insufficient to handle increased demand
- bariatric surgery
what vitamin deficiency historically occurred in areas where corn was the major source of protein and calories in the diet?
niacin b3
metabolic shunting carcinoid tumors increases risk for what vitamin deficiency?
niacin B3
-excessive serotonin shunts tryptophan away from usual metabolic pathway
isoniazid for TB puts patients at risk for what vitamin deficiency?
niacin B3
also pyridoxine b6
what vitamin deficiency is especially concerning in pregnant women?
folate
what vitamin deficiency are infants/ children fed unsupplemented goat’s milk at risk of developing?
folate
dilantin, sulfasalazine increase risk of deficiency of what vitamin?
folate
pernicious anemia (IF not produced or secreted), resection of stomach/ ileum, and gastric atrophy increase risk of what deficiency?
cobalamin b12
strict vegetarian diet w/o supplementation increases risk for what deficiency?
cobalamin b12
increased requirements for wound healing/ burns increase risk of what vitamin deficiency?
vitamin C
tryptophan is a precursor to what vitamin?
niacin b3
