32 Vitamins, Minerals, and Trace Elements Flashcards Preview

GI > 32 Vitamins, Minerals, and Trace Elements > Flashcards

Flashcards in 32 Vitamins, Minerals, and Trace Elements Deck (19)
Loading flashcards...

Vitamins and Minerals

  • Fat Soluble Vitamins
  • Water Soluble Vitamins
    • Energy
    • Hematopoietic
    • Ascorbate
  • Macro-minerals
  • Trace minerals

  • Fat Soluble Vitamins
    • ADEK
  • Water Soluble Vitamins
    • Energy
      • Thiamine (B1)
      • Riboflavin (B2)
      • Niacin (B3)
      • Pantothenic acid (B5)
      • Pyridoxine (B6)
      • Biotin
    • Hematopoietic
      • Folic acid
      • B12
    • Ascorbate (C)
  • Macro-minerals
    • Calcium
    • Phosphorous
    • Magnesium
    • Sodium
    • Potassium
    • Chloride
  • Trace minerals
    • Zinc
    • Iron
    • Copper
    • Selenium
    • Chromium
    • Manganese
    • Iodine
    • Fluoride
    • Molybdenum
    • Cobalt
    • Vanadium


Vitamin A (p.5-7)

  • synthesized from/
  • Critical component in/
  • retinoic acid
  • Good sources
  • Too much
  • Too little

  • Retinol, also synthesized from plant caroteniods
  • Critical electron shuttling component in vision
  • Vitamin A (retinoic acid)
    • Ligand for RXR (retinoic acid receptor) that helps regulate nuclear lipid receptor function, in turn controlling cell differentiation, growth, metabolism, inflammation
  • Good sources – meats, eggs, carrots, cantalope
  • Too much – can occur when used to treat acne, psoriasis. Induces birth defects, abortion
  • Too little – night blindness, impairment of immune cell function, follicular keratosis 


Vitamin D (p.9)

  • synthesized from/
  • Ligand for/
  • Works in concert with/
  • Helps regulate/
  • Good sources
  • Too much
  • Too little

  • Hydroxycholecalciferol, also synthesized from cholesterol in skin exposed to UV light
  • Ligand for a nuclear lipid receptor (Vitamin D receptor) that regulates gene expression
  • Works in concert with parathyroid hormone to regulate expression of enzymes critical for calcium absorption from gut and calcium resorption from kidney
  • Helps regulate immune cell function, insulin secretion, blood pressure
  • Good sources - meat, fish, eggs, milk
  • Too much – hypercalcemia
  • Too little – Rickets, bone demineralization


Vitamin K (p.11-12)

  • required cofactor for/
  • Vitamin K-dependent carboxylation occurs only on/
  • Other

  • required cofactor for a carboxylase that adds CO2 to glutamic acid, resulting in its conversion to gamma-carboxyglutamic acid (Gla)
  • Vitamin K-dependent carboxylation occurs only on specific glutamic acid residues in a small number of proteins that use carboxy-glutamate in calcium binding
  • Thrombin, blood clotting


Thiamine (B1) (p.15)

  • Critical cofactor for/
  • Dehydrogenases/
  • Transketolase/
  • Good sources
  • Too much
  • Too little

  • Critical cofactor for enzymes important in energetics and “information management” = genome function
  • Dehydrogenases (pyruvate, ketoglutarate, ketoacid) that feed electrons into TCA cycle and mitochondria
  • Transketolase, a critical pentose shunt enzyme, leads to formation of ribose-1-phosphate - a constituent of ATP, GTP, DNA, RNA
  • Good sources – grains, legumes, nuts, leafy vegetables
  • Too much – toxicity not observed
  • Too little – Beri-beri
    • beri-beri could not be transmitted, prevented by an amine in husk of rice, later purified and named thiamine “vitamine"


Riboflavin (B2) (p.16)

  • available
  • critical cofactor in /
  • Good sources
  • Too much
  • Too little

  •  Vitamin B2, only dietarily available,
  • critical cofactor in enzymes catalyzing electron transfer reactions
  • Good sources – leafy plants, meats, grains, milk, eggs
  • Too much – no recognized toxic effects
  • Too little – Ariboflavinosis.  Alcoholics, anorexics at risk


Niacin (B3) (p.17)

  • Serves as critical component of the/
  • Too much
  • Too little

  • Serves as critical component of the e-transferring cofactors NAD, NADP
  • Too much – no toxicity from dietary ingestion, only from over-supplementation: flushing, hepatotoxity from extended consumption of >500 mg/day
  • Too little – pellagra, problem when diet depends too heavily on CHO sources such as corn.  Manifested by dermatitis, hyperkeratosis, dementia, mild retardation


Pantothenic Acid (B5)

  • Fundamental cofactor for/
  • Good sources
  • Too much
  • Too little

  • Fundamental cofactor for acetylation and acyl transfer reactions - post-translational protein modification and fatty acid metabolism
  • Good sources – fish, chicken, milk, yogurt, eggs, lentils, peas, mushrooms
  • Too much – well tolerated, nausea and diarrhea when >1.2 gm/day
  • Too little – Noted in malnourished POWs, numbness and burning sensation in feet relieved with pantothenic acid supplementation


Pyridoxine (B6)

  • available
  • cofactor in
  • Good sources
  • Too much
  • Too little

  • Vitamin B6, only dietarily available,
  • cofactor in enzymatic reactions: transamination, deamination, decarboxylation
  • Good sources – fish, fowl, leafy vegetables, potatos, nuts
  • Too much – sensory neuropathy from over-consumption of supplements (> 1 gm/day)
  • Too little – Alcoholics at risk, but generally uncommon.  Excessive associations made between low pyridoxine and incidence of various health problems, benefits of supplementation not strongly supported


Biotin (p.22)

  • Part of/
  • synthesized by/
  • Serves as cofactor for/
  • Good sources
  • Too much
  • Too little
  • Symptoms of biotin deficiency include/

  • Part of “B complex” vitamins,
  • synthesized by bacteria, yeast, molds, algae and some plants. 
  • Serves as cofactor for enzymes that carboxylate (add CO2) biomolecules
  • Good sources – yeast, wheat bran, cooked eggs, liver
  • Too much – no known toxicity
  • Too little – observed to occur upon extended consumption of raw eggs (white) - promoting avidin-biotin complex formation and poor absorption
  • Symptoms of biotin deficiency include hair loss and red rash around eyes, nose, mouth, and genitalia.
    • Neurologic symptoms include depression, lethargy, hallucination, and numbness and tingling of the extremities.
    • The facial rash, together with an unusual facial fat distribution, have been termed the "biotin deficient face"


Folic Acid (p.24)

  • Mediates/
  • methotrexate
  • Good sources
  • Too much
  • hyperhomocysteinemia

  • Mediates one-carbon transfer reactions that plays  key role in purine, pyrimidine and methionine/homocysteine metabolism
  • The anti-cancer drug methotrexate is a folate analog - inhibits metabolism and utilization
  • Good sources - To limit neural tube defects (formerly 1/1000) 15 yr ago FDA mandated addition of 1.4 mg folic acid/kg to refined grain products also typically enriched with niacin, thiamin, riboflavin and iron (breads, pasta, rice, cereals).  Also spinach, asparagus, lentils, beans
  • Too much – no known toxicity
  • 2007: The AHA decreed hyperhomocysteinemia is not a risk factor for CVD.
    • The AHA recommends against use of folic acid and B vitamin supplements to reduce the risk of heart disease and stroke


Vitamin B12 (p.25)

  • cofactor for
  • Good sources
  • Too much
  • Too little
  • what increase risk
  • Drug interaction
  • The AHA does not recommend B vitamin supplements to reduce the risk of /

  • Cobalamin, a cofactor for two enzymes
    • methionine synthase (converts homocysteine to met), with met important for S-adenosyl methionine synthesis and downstrean DNA/RNA methylation
    • L-methylmalonyl-CoA mutase catalyzes succinyl CoA formation, an intermediate critical in energy metabolism, heme biosynthesis
  • Good sources – shellfish, fish, all meats, eggs, milk
  • Too much – no known toxicity from supplementation
  • Too little – causes pernicious anemia (2% incidence, >60 yr olds in US), with 10-15% people over 60 B12 deficient
  • Gastritis, ulcers, autoimmune disorders affecting gut, alcoholism, strict vegan diet all increase risk
  • Drug interaction - B12 absorption from foodstuffs needs low pH in gastric compartment. Proton pump inhibitors (omeprazole) but not H2 blockers (Tagamet, Pepcid, Zantac) may induce B12 deficiency after 2-3 yr. 
    • Nitrous oxide (N2O) inhibits B12-dependent enzymes, can induce B12 deficiency
  • The AHA does not recommend B vitamin supplements to reduce the risk of heart disease and stroke


Ascorbic Acid (Vitamin C) (p.29)

  • Humans, unlike most mammals cannot synthesize/
  • antioxidant and a cofactor for/
  • Good sources
  • Too little
  • what decrease Vit C (and E) levels
  • Too little/
  • Too much

  • Humans, unlike most mammals cannot synthesize ascorbate
  • antioxidant and a cofactor for collagen, norepinephrine and carnitine biosynthesis
  • Good sources – fruits, tomatos, peppers, broccoli, potatoes
  • Too little – Scurvy.
    • cured by eating oranges, lemons, limes.
    • Symptoms include bleeding and bruising, hair and tooth loss, joint pain and swelling, all related to weakening of blood vessels, connective tissue and bone - all containing collagen
  • Smoking, fast food decrease Vit C (and E) levels
  • Too much – no apparent toxicity, plasma saturated at 400 mg/day


Vitamin E

  • synthesized by/
  • Scavenges/
  • E deficiency
  • Good sources
  • alpha-tocopherol blood levels in adults

  • Tocopherol, also synthesized by gut bacteria
  • Scavenges free radicals and inflammatory oxidants - limits secondary oxidation of fats in membranes and lipoproteins
  • No known acute pathologic manifestations in E deficiency
  • Good sources – oils, plant leaves, nuts, avocados
  • alpha-tocopherol blood levels in adults 
    • 27 % of European descent, 41% of African-Americans, 28% of Hispanic-Americans and 32% of “other” have < 20 mM Toc, a level identified because of possible increased risk for cardiovascular disease below this level


Dietary Supplement Health and Education Act (DSHEA)

  • “Draws the line” between/
  • Dietary supplement
  • who's responsible for ensuring that ingredients are “safe"
  • Dietary supplements can make structure/function claims that the product can/
  • what constitutes an unapproved--and thus illegal--drug

  • “Draws the line” between pharma- and nutriceuticals
  • Dietary supplement - oral product containing a "dietary ingredient"    (vitamins, minerals, herbs or other botanicals, amino acids, enzymes, organ tissues, glands)
  • Manufacturer responsible for ensuring that ingredients are “safe"
  • Dietary supplements can make structure/function claims that the product can support the structure or function of the body
    • “L-arginine helps build muscle mass“  (Nitro Rx)
    • “The antioxidant vitamin E helps improve your sex life"
    • “Resveratrol helps prevent heart disease"
  • A product sold as a dietary supplement and promoted on its label or in labeling as a “treatment, prevention or cure” for a specific disease or condition” is an unapproved--and thus illegal--drug


There is a huge market for nutraceuticals

  • $100+ billion $$/yr of products sales in USA
  • Similar annual sales in 3 other regions:  Europe, Asia and combining the markets of Canada, Central, South America
    • Australia/NZ half this
  • Increasing “alternative medicine” practice by non-medical people
  • Growing number of health conscious consumers
  • Public perception of the positive effects of vitamins and nutritional supplements on health ….. due to widely publicized reports of “scientific findings” supporting such claims that lack rigor


Antioxidant and Other Vitamins:
Is supplementation a useful strategy to prevent cancer and limit CV and other diseases? (p.33+39)

  • Hypothesis
  • Vitamin E
  • Simvastatin decreases/
  • Antioxidants (Vit E, Vit C, beta-carotene)

  • Hypothesis - Antioxidant vitamins inhibit the oxidation and/or uptake of LDL, a critical step in atherogenesis
  • Vitamin E
    • Greater than recommended (22.5 IU/day) levels of Vit E are required to significantly increase blood levels of Vit E
  • Simvastatin decreases
    • 12% total mortality
    • 17% vascular mortality
    • 24% acute CV events
    • 27% stroke
  • Antioxidants (Vit E, Vit C, beta-carotene)
    • No benefit or harm observed


Conditions Motivating Vitamin Level Determination or Consideration of Vitamin Supplementation

  • Energy expenditure increased
  • Protein intake increased
  • Skeletal disease or tissue injury
  • Fluid imbalances, major blood loss
  • Immune response activation
  • Following clinical conditions
    • Anemia
    • Alcoholism
    • Drug abuse
    • Liver / kidney disease
    • Trauma
    • Skin rash
    • Dry eyes
    • Poor wound healing
    • HIV


Overall Lessons/Take home message

  • Fat soluble vitamins co-absorbed with dietary fat, excess consumption/
  • Water soluble vitamins have greater/
  • Vitamin requirements will increase with/
  • Vitamin deficiencies are frequently due to/
  • Recommend

  • Fat soluble vitamins co-absorbed with dietary fat, excess consumption may be toxic
  • Water soluble vitamins have greater rate of turn-over, greater likelihood of deficiency
  • Vitamin requirements will increase with trauma
  • Vitamin deficiencies are frequently due to inadequate dietary intake (dieting, food faddism, anorexia, chronic alcoholism, long-term dialysis, inadequate TPN, GI/kidney disease)
  • Recommend a fruit and vegetable-rich diet (and diversion of dietary supplement budget to a red wine allocation!)
  • Don't memorize mechanisms of actions of vitamins