Nutrion Final: Misc B Vitamins Flashcards
- What are the numbers still associated with each B vitamin? (B complex)
The order that they were found in, the number has no chemical or medical significance
- Why might the popular term B-complex be misleading? (B complex)
the daily requirements for the different vitamins is different, not all of the vitamins are present in the same foods, some of the operate together in the same cell reaction but they also have individual functions, the therapeutic use of one does not increase the requirements of the others
- What are some similarities among some members of the B-vitamin family? (B complex)
Four are required for mitochondrial energy production (thiamin, riboflavin, niacin, pantothenic acid), Two are required for nucleic acid synthesis (folic acid and B12), Activation of one may require coenzyme function of one or more of the others causing some to share deficiency symptoms, Many are non-toxic and have no tolerable upper limit (thiamin, riboflavin, biotin, pantothenic acid, B12)
- Which B-vitamins are parts of the “enrichment” of refined grain products? (B complex)
Thiamin, folic acid, riboflavin, niacin
- Are all B-vitamins non-toxic? (B complex)
No, both niacin and B6 can be toxic in high amounts
- What general functional role or roles does this vitamin play in human biology? (Thiamin)
Mitochondrial energy production, transketolase for pentose phosphate pathway—provides ribose-5-phosphate for nucleotide synthesis
- What enzyme function can be used to measure thiamin nutritional status? (Thiamin)
Transketolase activity in RBB’s used to detect tissue deficiency of thiamin
- What tissues or systems are primarily affected by deficiency of this vitamin? (Thiamin)
Nerve tissue-wet beriberi, congestive heart failure, edema-dry beriberi, cerebral symptoms-“cerebral” beriberi or Wernicke-Korssakoff Syndrome—movement and gait disorder, mental dysfunction…peripheral neuropathy, central neuropathy, heart problems
- Into what foods is this vitamin typically added? (Thiamin)
Rice, flour
- What is the most likely cause for deficiencies of this vitamin in the industrialized world? (thiamin)
Alcoholism
- What general functional role or roles does this vitamin play in human biology? (riboflavin)
Co-enzyme for numerous oxidation-reduction reactions, energy metabolism antioxidant reactions, liver detoxification
- What tissues or systems are primarily affected by deficiency of this vitamin? (riboflavin)
Liver
- What are the most likely causes for deficiencies of this vitamin in the industrialized world? (riboflavin)
Alcoholism, anorexia
- Into what foods is this vitamin typically added? (riboflavin)
White flour, white rice
- What diseases are being investigated for clinical use of this vitamin and what is the current understanding of its value? (riboflavin)
Cataracts prevention-could help protect lent through antioxidant co-enzyme role
migraine treatment-high doses help reduce frequency and duration
- Why is it difficult to design a riboflavin supplementation trial in which the subjects are truly blinded to whether they are receiving riboflavin or placebo? (riboflavin)
Urine will turn yellow for people who are receiving riboflavin as opposed to those who are not
- What is the significance of the existence of two different molecular forms of this vitamin? (niacin)
One form will help lower cholesterol and the other forms NAD and is used in the body…high levels of Nicotic Acid have pharmacological effects but don’t have an effect on the body’s metabolism while Nicotinamide helps the body form NAD and has no pharmacological effects
Niacin/Nicotinic Acid is found naturally only in plants vs. Niacinaminde/Nicotinamide is found naturally only in animal tissue
- What pathway is available for production of niacin coenzyme in the absence of a dietary source of the vitamin? (niacin)
Mitochondrial energy production uses NAD/NADH
Anabolic reactions such as biosynthesis of fatty acids use NADP/NADPH
Some re-dox reactions as well
- What general functional role or roles does this vitamin play in human biology? (niacin)
Making NAD/NADH and NADP/NADPH
- What tissues or systems are primarily affected by deficiency of this vitamin? (niacin)
Skin
- Into what foods is this vitamin typically added? (niacin)
Refined carbohydrates
- What is the difference between various formulations of supplemental niacin?
Niacin-immediate release will have flushing, slow release
Niacinaminde—better tolerated but has no effect on cholesterol and may still raise liver enzymes
For reduced side effects: Inositol complex, NiaSpan—Rx form
- What diseases are being investigated for clinical use of this vitamin and what is the current understanding of its value? (niacin)
Pellagra-4 D’s: Dermatitis, Diarrhea, Dementia, Death
- What toxic effects, if any, are possible for this vitamin? (niacin)
Flushing, hepatotoxicity, GI irritation, headache, impaired glucose tolerance, elevated uric acid
- What precautions must be taken when recommending niacin therapy to lower serum cholesterol and triglycerides? (niacin)
Need to monitor patient to make sure they don’t develop any potential side effects to the niacin, monitor their liver enzymes to make sure they don’t develop any problems with liver function
- What health conditions contraindicate the use of high-dose niacin therapy? (niacin)
peptic ulcer disease, migraine headaches, gout, cardiac arrhythmias
- What general functional role or roles does this vitamin play in human biology? (Pantothenic acid)
Structural component of coenzyme A and acyl-carrier protein
- What diseases are being investigated for clinical use of an analog of this vitamin and what is the current understanding of its value? (Pantothenic acid)
Lowers blood cholesterol and triglycerides without toxicity using pantethine (pantothenic acid derivative)
- What are the biochemical names associated with this B vitamin? B6
Vitamin forms: Pyridoxine, Pyridoxal, Pyridoxamine
Co-Enzyme forms: Pyridoxal-5-Phosphate (PLP), Pyridoamine-5-Phosphate (PMP)
- What general functional role or roles does this vitamin play in human biology? B6
Amino acid metabolism, neurotransmitter synthesis and myelin formation, heme synthesis, nucleic acid synthesis,
- How does vitamin B6 support nervous system function?
Neurotransmitter synthesis and myelin formation
- How does vitamin B6 affect hormone function?
PLP appears to bind steroid hormone receptors in a manner that inhibits hormone binding-could play a role in hormone disorders
- What tissues or systems are primarily affected by deficiency of this vitamin? B6
Nervous tissue, oral cavity, immune function, cognitive decline, cardiovascular disease, kidney stones,
- What age-group is most at risk for deficiencies of this vitamin? B6
elderly
- What additional causes are there for vitamin B6 inadequacy?
Genetic diseases and other disorder have been identified
- What diseases are being investigated for clinical use of this vitamin and what is the current understanding of its value? B6
Cardiovascular disease prevention, carpal tunnel syndrome, PMS
- What toxicity or other side effects are possible for this vitamin? B6
Sensory neuropathy with intake of hundreds or thousands of milligrams, suppression of lactation has been reported at 600mg/day
- What general functional role or roles does this vitamin play in human biology? Biotin
Coenzyme for reactions involving carboxyl group transfers
- What dietary habit supplies excess amounts of a glycoprotein that reduces biotin availability? Biotin
Consumption of large amounts of raw egg whites
- Why is there renewed interest in biotin status during pregnancy? Biotin
Biotin status may be marginal in pregnancy in up to 50% of women, and mild deficiency has led to birth defects
- Does the Daily Value for biotin reflect current understanding of the requirement for this vitamin? Biotin
No…it reflects the old numbers that were thought to be the RDA not the new numbers which are as low as 10% of what the RDA says it is
- What diseases are being investigated for clinical use of this vitamin and what is the current understanding of its value? Biotin
Diabetes mellitus
