Water-Soluble Vitamins Flashcards
1
Q
What are the water-soluble vitamins?
A
B1 B2 B3 B5 B6 B7 B12 Vitamin C Folic Acid
2
Q
- Active form is thiamine pyrophosphate (TPP)
- Involved in energy metabolism, nerve and muscle function
- Oxidative decarboxylation reactions
a) pyruvate dehydrogenase
b) alpha-ketoglutarate dehydrogenase
c) branched chain-alpha-ketoacid dehydrogenase - Transketolase Reaction in pentose phosphate pathway
- Primary food source: yeast, organ meat, pork, legumes, beef, whole grain, nuts
- deficiency seen in polishing of cereals (rice) and chronic alcoholism (ethanol inhibits the absorption of thiamine)
A
Thiamine (B1)
3
Q
- a Thiamine deficiency
- Cardiovascular system mainly involved
- High output cardiac failure, four chamber dilated heart
- Dependent edema, breathlessness, palpitation, orthopnea
- Acute circulatory failure, death
A
Wet Beriberi
4
Q
- a Thiamine deficiency
- CNS involved
- Polyneuritis, peripheral neuropathy
- Progressive muscle wasting, foot drop, wrist drop, loss of reflexes, paresthesia
- Difficulty in walking, bedridden
A
Dry BeriBeri
5
Q
- a Thiamine deficiency
- Born to thiamine deficient mother
- Sleepiness, restlessness
- Cyanosis, breathlessness, cardiac failure
- Sudden death cardiac failure
A
Infantile Beriberi
6
Q
- Aka Wet Brain
- Secondary to alcohol abuse
- Key signs: vision changes, ataxia and impaired memory
- Combined manifestation of Korsakoff’s Psychosis [loss of memory, retrograde and anterograde, and confabulatory psychosis, reports of events that never happened] and Wernicke’s Encephalopathy [Nystagmus, ophthalmoplegia, cerebellar ataxia, confusion]
- Treatmen: infusion of thiamine along with other symptomatic management
A
Wernicke-Korsakoff Syndrome
7
Q
- Active forms are: Flavin mononucleotide (FMN) and Flavin adenine dinucleotide (FAD)
- FAD and FMN reversibly accept H+ ions to become reduced FADH2 and FMNH2
- important for fat, carb, and protein metabolism
- Component of electron transport chain complexes
- plays a role in drug and steroid metabolism
- Sources: egg, dairy, meat, whole grain, cereals, oat meal, clams, squid, mushroom, broccoli, legumes
- Light sensitive-requires opaque bottle
A
Riboflavin (B2)
8
Q
- lesions of the mucocutaneous surfaces of mouth and skin
- Cheilosis (fissures on lips - Angular cheilitis and stomatitis (fissures and inflammation at the angles of the mouth)
- Glossitis (magenta colored tongue)
- Corneal neovascularization
- Seborrhic dermatitis (inflammation of skin with excess fat over the face (greasy skin) particularly at angles of the nose
- Anemia
A
Riboflavin Deficiency
9
Q
- Nicotinic acid and nicotinamide and derivatives (NAD+, NADH, NADP+, NADPH)
- Coenzyme for oxidoreductases
- NAD(H) dehydrogenases catalyze oxidative pathways
- NADP(H) reductases catalyze reductive biosynthesis
- Used in treatment of hyperlipidemia as it lowers triacylglycerol in VLDL
- Sources: beans, milk, lean meats, liver, eggs, unrefined and enriched grains and cereal
- Corn has indigestible niacin in the form of niacytin
- Tryptophan can be converted to this with an efficiency of 60:1 by weight, so _____ is synthesized in our body
A
Niacin (B3)
10
Q
- Pellagra
- Found in corn based diets, chronic alcoholics, Hartnup disease, Carcinoid syndrome
- deficiency of micronutrients required for the conversion of tryptphan - iron, riboflavin, pyroxidine)
- Early signs: loss of appetite, generalized weakness and irritability, abdominal pain, and vomiting
- Late signs: 3Ds; diarrhea, dermatitis (Casal’s necklace), dementia
A
Niacin (B3) Deficiency
11
Q
- Component of coenzyme A (CoA) which transfer acyl groups
- essential nutrient for synthesis and metabolism of carbs, proteins, and lipids
- Sources: widely distributes, eggs, liver and yeast
A
Pantothenic Acid (B5)
12
Q
- Very rare and not well characterized
- Signs include: fatigue, weakness, numbness, paresthesia, muscle cramps, restlessness, malaise, sleep disturbance, burning foot syndrome
A
Pantothenic Acid (B5) Deficiency
13
Q
- Converted to active form Pyridoxal phosphate (PLP)
- Coenzyme for more than 100 enzymes
- Involved in amino acid metabolism (all transamination reactions), heme (ALA synthase) and neurotransmitter synthesis (dopa decarboxylase)
- Sources: legumes, nuts, wheat bran, meat
- High doses have been used to treat carpal tunnel, premenstrual syndrome, schizophrenia, autism but not found effective
- decreased in availability as coenzyme by medications isoniazid, L-dopa, penicillamine, and cycloserine
- not synthesized in body
A
Pyridoxine (B6)
14
Q
- Seen in chronic alcoholics, isoniazid therapy for TB, women taking oral contraceptive pills, infants fed with formulas low in vitamin B6
- Manifestations include: peripheral neuropathy, personality changes, convulsions, depression, insomnia, microcytic hypochromic anemia, homocysteinemia
A
Pyridoxine (B6) Deficiency
15
Q
- Coenzyme for all carboxylases
- Acts as a carrier of CO2
- Widely available and supplied by intestinal bacteria
- some synthesized in body
A
Biotin (B7)
16
Q
- Rare
- Consumption of raw egg white as a protein component in diet (20 eggs/day)
- Symptoms: dermatitis, glossitis, loss of appetite, nausea
A
Biotin (B7) Deficiency
17
Q
- Strong reducing agent
- Biologically active in form or in oxidized form
- Not synthesized by humans
- Sources: citrus fruits, green veggies, tomatoes, and potatoes
- Rapidly absorbed from intestine but not significantly stored
- Requirements increase from free radical generation during smoking, hemodialysis, pregnancy, and stress
- Coenzyme for proylyl hydroxylase and lysyl hydroxylase (collagen production)
- Coenzyme for dopamine beta-hydroxylase (conversion of DOPA to NE)
- Participates in Carnitine Biosynthesis
- Helps absorption of non-heme iron
A
Ascorbic Acid (Vitamin C)
18
Q
- Plays a key role in one carbon metabolism
- Converted to tetrahydrofolate (THF)
- Source: green leafy veg, easily destroyed by overcooking
- Found in polyglutamate form (less efficient for absorption) and converted to monoglutamates by intestinal gamma glutamyl hydrolases, converted to THF within small intestinal muscosa before entering
- Involved in purine biosynthesis
- Involved in biosynthesis of thymidine monophosphate, dTMP from dUMP
- Involved in conversion of homocysteine to methionine
- Involved in interconversion of serine and glycine
- not synthesized in body
A
Folic Acid
19
Q
inhibit bacterial dihydropteroate synthetase and not the human enzymes thereby inhibit bacterial multiplication due to decreased THF for DNA synthesis.
A
Sulfonamides
20
Q
(anticancer drug) inhibits dihydrofolate reductase thereby decreases the availability of THF and hence inhibit DNA synthesis in rapidly proliferating human cells.
A
Methotrexate
21
Q
- Causes: Increased demand during pregnancy, poor intestinal absorption, chronic alcoholism, overcooking of green leafy veg, treatment with dihydrofolate reductase inhibitor
- Presents 3-4 months after dietary deficit due to liver storage
- Megaloblastic anemia: decreased purines and dTMP, decreased nucleas maturation
- hypochromic and macrocytosis RBCS
- Hypersegmented neutrophils
- anisocytosis
- poikilocytosis
- Hypercellular bone marrow with accumulation of primitive cells
- Issues with epithelial cell surfaces
- Pregnancy related complications: infertility, prematurity, fetal loss, neural tube defects
A
Folic Acid Deficiency
22
Q
- Multiple chemical forms with a cobalt atom at the center of a corrin ring
- Deoxyadenosylcobalamin and methylcobalamin
- Source: synthesized solely by microorganisms, milk, cheese, eggs, meat
- For absorption, binds to heptocorrin in stomach… heptocorrin digested by pancreatic trypsin in small intestine.. cobalamin binds to intrinsic factor (IF)… IF-cobalamin complex attaches to cubilin in ileum.. IF-cobalamin complex endocytosed into ileal cells where IF is destroyed… cobalamin appears in portal blood after 6H attached to transcobalamin (TC) II and transported to destinations
A
Cobalamin (B12)
23
Q
- One of 2 natural forms of cobalamin
- A coenzyme for methylmalonyl CoA mutase, conversion of methylmalonyl CoA to succinyl CoA
A
Deoxyadenosylcobalamin
