Water Soluble Vitamins Flashcards
What are the functions and signs of deficiency or toxicity for thiamin (Vitamin B1)?
Functions: (TDP or TPP) Coenzyme for metabolism in all cells, esp. glycolysis, TCA cycle, amino acid metabolism, decarboxylation, transketolation rxns, nerve conduction
Deficiency: Dry and Wet Beri-Beri, Wernicke-Korsakoff syndrome.
Toxicity: little to none due to renal excretion
What are the food sources and risk of deficiency of thiamin (B1)?
Food sources: Whole grains/germ, enriched grains, lean pork, legumes
Risk of deficiency: Alcoholics, Elderly, renal dialysis patients, high carb diet (rice/unenriched grains), anorexia or starvation refeeding (diminished B1 stores in setting of increased metabolic demand from CHO intake), bariatric surgery, dietary deficiency in diets high in rice.
What are the general conditions in which a physician should consider the possibility of vitamin deficiency?
If more than 1 of the following are present:
Poverty (poor diet quality)
Chronic disease states (esp. those impacting absorption)
Advanced age
Dietary restrictions (celiac disease, food allergies, vegans)
High requirements (infants/children/pregnancy/lactation)
What are the functions and signs of deficiency or toxicity for riboflavin (Vitamin B2)?
Function: Part of two enzymes FAD and FMN (flavin mono nucleotide), acts in redox reactions in TCA cycle and oxidative phosphorylation, amino acid and fatty acid metabolism, metabolism of Vit K, folate, B6, and Niacin (B3).
Deficiency: Oral-Ocular-Genital syndrome: ORAL - Chelosis, cracking of lips and angular stomatosis, sores at corners of mouth; OCULAR - increased vascularization of conjunctiva and photophobia, GENITAL - seborrheic dermatitis and scrotal dermatitis.
Toxicity: Low due to renal excretion
What are the food sources and risk of deficiency of Riboflavin (Vitamin B2)
Food sources: Liver, wheat germ, dairy, meats and poultry, leafy greens. UV light destroys the vitamin.
Risk of deficiency: Women, infants, elderly, adolescents, developing countries with low animal source foods. Subclinical deficiency of low glutathione reductase levels may be seen in women on birth control pills, elderly, eating disorders, HIV, DM, chronic heart disease.
What are the functions and signs of deficiency or toxicity of niacin (B3)?
Functions: A substituent of NAD and NADP, functions in many energy related pathways including glycolysis, TCA cycle, oxidative phosphorylation, fatty acid synthesis and oxidation.
Deficiency: Pellagra - Four D’s Dermatitis, Dementia, Diarrhea, Death,
Toxicity: Generally non-toxic, >6 grams/day leads to peripheral vasodilation and flushing, increased serum uric acid, glucose intolerance, liver damage.
What are the food sources and risks of deficiency of niacin (B3)?
Food sources: Meats, poultry, fish, peanut butter, legumes are major sources of preformed niacin. Tryptophan is niacin precursor and is found in milk and eggs.
Risks of deficiency: months of poor intake, very high corn diets, malabsorption, alcoholism, cirrhosis, metabolic “shunting” (carcinoid tumors creating serotonin sucking tryptophan away from niacin production), Isoniazid (TB med), Hartnup disease
What are the functions and signs of deficiency or toxicity of folate?
Function: 1 carbon transfers, esp. in synthesis of nucleic acids and metabolism of certain amino acids, conversion of homocysteine to methionine. Methyl-donor in epigenetics
Deficiency: Macrocytic anemia, hyperhsegmented neutrophils, inc. plasma homocysteine, inc. occurrence of neural tube defects, MTHFR gene raises folate needs in individuals
What are the food sources and risks of deficiency of folate?
Food source: “Folate from Foliage”, deep green leaves, broccoli, orange juice, whole grains, destroyed by prolonged cooking, fortification of grains in US
Risk of deficiency: Pregnant women, breastfed children of deficient mother, infants/children fed goat’s milk, Medications (dilantin, sulfasalazine), chronic hemolytic anemia or blood loss
What are the functions and signs of deficiency or toxicity of cobalamin (B12)?
Functions: closely related to folate metabolism, 1-carbon transfers, odd chain length fatty acids, regenerates folate in methionine formation, methylmalonyl-CoA to succinyl-CoA (lipid and CHO metabolism), protein and nucleic acid synthesis
Deficiency: Microcytic anemia, hypersegmented neutrophils neurologic problems (paresthesias, gait problems, depression) Deficiency is very slow to develop as the RDA is 2.4ug/day and the liver can store 1-10 GRAMS (10^6 greater)
What are the food sources and risks of deficiency of Cobalamin (B12)?
Food sources: Animal products only!
Risk of Deficiency: Pernicious anemia (IF not produced, elderly), Gastric atrophy (elderly), Resection of stomach or ileum (gastric surgery, short gut syndrome), Vegans, breastfed infants of deficient mothers, elderly, autoimmune conditions (Ab to IF cells)
What are the functions and signs of deficiency or toxicity of Pyridoxine (B6)?
Function: critical in amino acid metabolism and interconversions.
Deficiency: Anemia, seizures, glossitis, +/- depression
Toxicity: Doses greater than 500mg/day = sensory ataxia, impaired position/vibratory sensation,
What are the food sources and risks of deficiency of Pyridoxine (B6)?
Food sources: Animal products, vegetables, whole grains (lost in processing, not enriched)
Risk of deficiency: Isoniazid medication (TB), end-stage renal disease/renal insufficiency, malabsorption diseases (celiac, Crohn’s disease, UC), genetic diseases such as homocystinuria, elderly with poor diet.
What are the functions and signs of deficiency or toxicity of Vitamin C?
Function: Antioxidant/reducing agent (=electron donor), Collagen synthesis, reduction of Fe3 -> Fe2, increased Fe absorption, norepinephrine synthesis
Deficiency: Scurvy (defective collage formation in capillary basement membranes) Loss of precursors of catecholamines and other vasoactive and neurotropic substances. Petechiae, bleeding gums, anemia, bruising, weakness/fatigue, painful joints
What are the food sources and risks of deficiency of Vitamin C?
Food sources: Fruits and vegetables, broccoli, green peppers, citrus, potatoes,
Risk of deficiency: Diets lacking in fruits and vegetables, Increased requirements for wound healing and burns, low income (poor diet), smokers, infant’s fed cow’s milk without supplementation.
