Nutrition I Flashcards
Describe the absorption of fat soluble vitamins and the cause of their toxicity.
(ADEK)- absorption dependent on gut (ileum) and pancreas. Toxicity is more common than for water soluble vitamins due to accumulation in fat (p.90)
Name the 10 water soluble vitamins.
A, B1 (thiamine, TPP); B2 (riboflavin FAD, FMN); B3 (niacin, NAD+); B5 (pantothenic acid: CoA); B6 (pyridoxine, PLP); B7 (biotin); B9 (folate); B12 (cobalamin); C (ascorbic acid) (p.90)
Which water soluble vitamin is the only one that does not wash out easily and is stored in the liver?
B12 (p.90)
Describe three symptoms associated with B-complex deficiencies.
Dermatitis, glossitis, and diarrhea (p.90)
What is the function of Vitamin A?
Vitamin A is an antioxidant, is a constituent of visual pigments (retinal), is essential for normal differentiation of epithelial cells into specialized tissue (pancreatic cells, mucus secreting cells), and prevents squamous metaplasia (p.90)
What conditions is Vitamin A used to treat?
Measles and AML (subtype M3) (p.90)
What foods are rich in Vitamin A?
Liver and leafy vegetables (p.90)
What are the symptoms associated with Vitamin A deficiency?
Night blindness, dry skin (p.90)
What are the symptoms associated with Vitamin A execss?
Arthralgias, fatigue, headaches, skin changes, sore throat, alopecia. It is a teratogen so negative pregnancy test is required before starting isotretinoin for severe acne (p.90)
What is the function of Vitamin B1 (thiamine)?
Part of thiamine pyrophosphate (TPP) which is a cofactor for several enzymes in decarboxylation reactions: pyruvate dehydrogenase (links glycolysis to TCA cycle); a-ketoglutarate dehydrogenase (TCA cycle); Transketolase (HMP shunt); Branched chain amino acid dehydrogenase. All of these enzymes (except for BCAD) are required for ATP synthesis (p.90)
Describe the pathology associated with Vitamin B1 deficiency.
Impaired glucose breakdown causes ATP depletion that is worsened by glucose infusion. Highly aerobic tissues (brain and heart) are affected first (p.90)
What are the classic symptoms of Wernicke-Korsakoff syndrome?
Confusion, opthalmoplegia, ataxia (the classic triad); confabulation, personality change, memory loss (permanent) (p.90)
Describe the pathology associated with Wernicke-Korsakoff syndrome.
Thiamine deficiency causes damage to medial dorsal nucleus of thalamus and mamillary bodies (p.90)
What are the symptoms of dry beriberi?
Polyneuritis symmetrical muscle wasting (p.90)
What are the symptoms of wet beriberi?
High output cardiac faliure (dilated cardiomyopathy), edema (p.90)
What is the function of Vitamin B2 (riboflavin)?
Serves as the cofactor in oxidation and reduction (i.e. FADH2) (p.91)
What are the symptoms of vitamin B2 deficiency?
Chelosis (inflamation of the lips, scaling, and fissures at the corners of the mouth); Corneal vascularization (p.91)
What is the function of Vitamin B3 (niacin)?
Constituent of NAD+, NADP+ (used in redox reactions) (p.91)
What is Vitamin B3 derived from and what cofactor is necessary for its synthesis?
Derived from tryptophan. Synthesis requires vitamin B6 (p.91)
What are the symptoms of vitamin B3 deficiency?
Glossitis. Severe deficiency leads to pellagra which is characterized by diarrhea, dementia, and dermatitis (p.91)
What can cause Pellagra?
Vitamin B3 deficiency; Hartnup disease (decreased tryptophan absorption), malignant carcinoid syndrome (increased tryptophan metabolism); and Izoniazid (decreased vitamin B6) (p.91)
What are the symptoms of vitamin B3 excess?
Facial flushing in pharmacologic doses (p.91)
What is the function of Vitamin B5 (pantothenate)?
Essential component of CoA (a cofactor for acyl transfers) and fatty acid synthase (p.91)
What are the symptoms of Vitamin B5 deficiency?
Dermatitis, enteritis, alopecia, adrenal insufficiency (p.91)
What is the funciton of Vitamin B6?
It is converted to pyridoxal phosphate, a cofactor used in transamination (eg. ALT, AST), decarboylation reactions, glycogen phosphorylase. Synthesis of cystathione, heme, niacin, histamine, and neurotransmitters including serotonin, epinephrine, norepinephrine, and GABA (p.91)
