Water-Soluble Vitamins Flashcards
What are the water-soluble vitamins?
B1 B2 B3 B5 B6 B7 B12 Vitamin C Folic Acid
- 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)
Thiamine (B1)
- a Thiamine deficiency
- Cardiovascular system mainly involved
- High output cardiac failure, four chamber dilated heart
- Dependent edema, breathlessness, palpitation, orthopnea
- Acute circulatory failure, death
Wet Beriberi
- a Thiamine deficiency
- CNS involved
- Polyneuritis, peripheral neuropathy
- Progressive muscle wasting, foot drop, wrist drop, loss of reflexes, paresthesia
- Difficulty in walking, bedridden
Dry BeriBeri
- a Thiamine deficiency
- Born to thiamine deficient mother
- Sleepiness, restlessness
- Cyanosis, breathlessness, cardiac failure
- Sudden death cardiac failure
Infantile Beriberi
- 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
Wernicke-Korsakoff Syndrome
- 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
Riboflavin (B2)
- 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
Riboflavin Deficiency
- 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
Niacin (B3)
- 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
Niacin (B3) Deficiency
- 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
Pantothenic Acid (B5)
- Very rare and not well characterized
- Signs include: fatigue, weakness, numbness, paresthesia, muscle cramps, restlessness, malaise, sleep disturbance, burning foot syndrome
Pantothenic Acid (B5) Deficiency
- 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
Pyridoxine (B6)
- 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
Pyridoxine (B6) Deficiency
- Coenzyme for all carboxylases
- Acts as a carrier of CO2
- Widely available and supplied by intestinal bacteria
- some synthesized in body
Biotin (B7)
- Rare
- Consumption of raw egg white as a protein component in diet (20 eggs/day)
- Symptoms: dermatitis, glossitis, loss of appetite, nausea
Biotin (B7) Deficiency
- 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
Ascorbic Acid (Vitamin C)
- 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
Folic Acid
inhibit bacterial dihydropteroate synthetase and not the human enzymes thereby inhibit bacterial multiplication due to decreased THF for DNA synthesis.
Sulfonamides
(anticancer drug) inhibits dihydrofolate reductase thereby decreases the availability of THF and hence inhibit DNA synthesis in rapidly proliferating human cells.
Methotrexate
- 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
Folic Acid Deficiency
- 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
Cobalamin (B12)
- One of 2 natural forms of cobalamin
- A coenzyme for methylmalonyl CoA mutase, conversion of methylmalonyl CoA to succinyl CoA
Deoxyadenosylcobalamin
- One of 2 natural forms of cobalamin
- A coenzyme for methionine synthase, conversion of homocysteine to methionine
Methylcobalamin
Major cobalamin transport protein in plasma
Transcobalamin II (TC II)
- Causes: malabsorption, inadequate dietary intake
- Previously well-nourished individuals have hepatic vitamin B12 reserves sufficient to last for up to several years (6 years) of complete dietary deprivation.
- Causes of malabsorption: Pernicious anemia (lack of IF due to gastric atrophy), congenital IF deficiency, Gastrectomy, ileal resection, tropical sprue, nitrous oxide inhalation, congenital TC II deficiency
- Manifestations: megaloblastic anemia, neurologic issues (bilateral neuropathy/degeneration of dorsal and lateral spinal columns (SCDS), methylmalonic academia and aciduria
Cobalamin (B12) Deficiency
What do these cause?
- Increased demand as during pregnancy.
- Poor intestinal absorption.
- Chronic alcoholism.
- Overcooking of green leafy vegetables.
- Treatment with dihydrofolate reductase inhibitor (methotrexate).
folate deficiency
What are the Active forms of Vit b2?
Flavin mononucleotide (FMN) and Flavin adenine dinucleotide (FAD)
Which vitamin is this? Thiamine
B1
Which vitamin is this? Riboflavin
B2
Which vitamin is this? Niacin
B3
Which vitamin is this? Pantothenic Acid
B5
Which vitamin is this? Pyridoxine
B6
Which vitamin is this? Biotin
B7
Which vitamin is this? Ascorbic Acid
Vit. C
Which vitamin is this? Cobalamin
B12
What vitamin deficiency is commonly seen in vegans?
Cobalamin
What vitamin deficiency is commonly seen in chronic alcoholics?
Thiamine
What vitamin deficiency is commonly seen in fat malabsorption disorders such as cystic fibrosis?
Fat soluble vitamins
The active form of which vitamin participates in oxidative decarboxylation reactions and trans ketolase reactions?
Thiamine
Pyruvate dehydrogenase complex, Alpha ketoglutarate dehydrogenase complex, branched chain alpha ketoacid dehydrogenase complex
Thiamine
Which vitamin deficiency DO you see with polishing of cereals or rice?
Thiamine
_____ is required as a coenzyme for the enzymes involved in energy metabolism, nerve and muscle function
Thiamine
____ is important for the metabolism of fat, carbohydrates, and proteins.
Riboflavin
This vitamin is a component of electron chance port chain complexes and plays a role in drug and steroid metabolism including detox
Riboflavin
What enzyme needs sufficient riboflavin?
Cytochrome p450s
Which vitamin is extremely light sensitive?
Riboflavin
Which vitamin, in high doses, is used in the treatment of hyperlipidemia as it lowers Triacylglycerol and VLDL?
Niacin
Pellagra in North America is found only among what three groups?
Chronic alcoholics, hartnup disease, carcinoid syndrome
What are the three D’s that pellagra manifests with?
Diarrhea, dermatitis, dementia
Deficiency of which vitamin can be induced by the use of which drug used for the treatment of tuberculosis?
Vitamin b6, isoniazid
High doses of which vitamin have been used to treat carpal tunnel syndrome premenstrual syndrome schizophrenia autism and diabetic but have not been found to be effective?
Vitamin b6
This vitamin acts as a coenzyme for all carboxylases participating in carboxylation reactions: pyruvate carboxylase, propionyl CoA carboxylase, acetyl CoA carboxylase.
Biotin
This vitamin is a coenzyme for prolyl hydroxylase and lysyl hydroxylase. It acts as an antioxidant and it participates in carnitine biosynthesis and it helps the stomach and absorption of non-heme iron
Vitamin c
Megaloblastic anemia, no neurological signs in this deficiency
Folic acid deficiency
Neither humans nor animals can synthesize this vitamin. It is only bacteria in the stomach of animals such as cows that can.
Cobalamin
Deficiency of which vitamin can cause pernicious anemia?
Cobalamin
Megaloblastic anemia seen with neurologic manifestations
Cobalamin deficiency
