59-60: Micronutrition Flashcards
Dietary Reference intakes
-system of nutrition recommendations from IMNA
-replaced original recommended daily allowance (RDA)
Reference values provided by Dietary Reference Intakes
-EAR
-RDA
-AI
-UL
Estimated average requirement (EAR)
-amount of nutrient estimated to meet the need of 50% of the healthy individuals in an age and gender group
Recommended Dietary Allowance (RDA)
-2 standard deviations ABOVE EAR
-sufficient to meet need of 97-98% healthy individuals in a group
Adequate Intake (AI)
-used when not enough evidence to set an EAR
-approx the average nutrient intake of a healthy population
Tolerable Upper Intake Level (UL)
-max level of daily intake of nutrient without any health risk
Micronutrients
-vitamins
-minerals
Vitamins
-fat-soluble (ADEK)
-water-soluble (B and C)
Minerals
-macro: Ca and Mg
-trace: iron, iodine, zinc, copper, selenium
Vitamin A
-retinol, retinal, retinoic acid
-produced from carotenoids, organic pigments in plants
-function as light sensor (cis retinal w opsins)
Vitamin A deficiency
-night blindness
Retinoic Acid (Vit A)
-like hormones (nuclear receptor_
-regulates cell growth/dif
-associated w nuclear and retinoid receptos
Carotenoids
-vit A precursor
-effective antioxidant
-may reduce risk of cancer
Vit A storage
-in liver
-as retinol palmitate
Vitamin D
-function as steroid hormones maintaining calcium homeostasis
-made from cholesterol intermediate
-made photochemically in skin
Vit A dietary sources
-dark green/ yellow veggies
-liver
-egg yolk
-butter
-whole milk
Vit D defiency
-insuff exposure to sunlight
-rickets in young children
-osteomalacia in adults
Vitamin D dietary sources
-Vit D milk
-saltwater fish
-liver
-egg yolk
Vitamin E
-occurs in diet as tocopherols and tocotrienols
-antioxidants
-protecting unsaturated fatty acids
-accumulate in lipoproteins, cellular membranes, fat deposits
-reduce risk of CVD by stopping oxidation of LDL
Vit E dietary sources
-veg oils rich in polyunsat fat
-deficiency is rare
Vitamin K
-required for post-trans modification of glutamic acid residues to y-carboxyglutamic acid residues (allow binding to Ca)
-essential for blood clotting
-essential for bone mineralization
Vitamin K epoxide reductase
-regenerates active form of vit K
Vit K dietary sources
-K1 in green veggies
-K2 by intestinal bacteria
-deficiency rare
Warfarin
-anticoagulant
-vit K ANTAgonist
-prevent thrombosis
-inhibits reductase
Thiamin (B1)
-rapidly converted to thiamin pyrophosphate and TRIphosphate
Thiamin pyrophosphate
-cofactor in enzyme catalysis
-thiazole ring strong nucleophile
Thiamin Triphosphate
-functions in transmission of nerve impulse in peripheral nerve membranes
Beriberi
-sever thiamin B1 deficiency
-muscular atrophy and weakness
-may occur in populations relying on rice or alcoholics
Riboflavin (B2)
-precursor of FAD and FMN
-milk, meat, eggs, cereal
Riboflavin (B2) deficiency
-rare
-angular chilitis, glossitis, and scaly dermatitis
-seen in chronic alcoholics
Niacin B3
-converted to NAD and NADP
-meats, peanuts, cereal
Pellagra
-severe Niacin B3 deficiency
-dermatitis, diarrhea, dementia
-rare
-alcoholics, pt w malabsorption, elderly
Pyridoxine (B6)
-converted to pyridoxal phosphate (transamination in aa metabolism = make NTs and sphingolipids)
-meat, veggies, whole grain cereal
Pyridoxine (B6) deficiency
-mild: irritability, nervousness, depression
-severe: peripheral neuropathy and convulsions
Biotin (B7)
-serves as cofactor for activation of CO2 in enzymes
-covalent bind to lysine in enzymes
-lots of foods
Biotin (B7) deficiency
-rare
-may occur when too much raw egg white
-avidin in egg forms tight complex with biotin
-preg women higher risk
Folic acid (B9)
-converted to tetrahydrofolate
-DNA synthesis and cellular proliferation
-rich in lots of food
Folic acid (B9) deficiency
-produces abnormal RBCs = anemia
-inc the risk of birth defects esp neural tube defect
-common in alcoholics
Cobalamin (B12)
-Co
-complex w proteins
-needed for methionine synthase and methylmalonyl-CoA mutase
Cobalamin B12 deficiency
-homocystein and methyl malonic acid accumulate
=anemia and neurological damage
-rare
-malabsorption diseases and long-term vegetarians
Vitamin C
-ascorbic acid
-needed for hydroxylation of lysine and proline side chains, which is necessary for collagen stability (healing)
-reducing agent
Vit C as a reducing agent
-aids absorption of iron by reducing it to Fe2+ in tummy
-protects vit A, E, B from oxidation
Vit C deficiency
-capillary fragility, easy bruising, dec immunocompetence
-scurvy (severe)
-smokers need more
-using vit c to cure cold is controversial
Scurvy
-dec wound healing
-osteoporosis
-hemorrhaging
-anemia
Calcium
-most abundant mineral in body
-makes bones
-serves as 2nd messenger
-req for many enzymes
-essential for blood coagulation and muscle contractility
Calcium serum level maintenace
-homeostasis
-deficiency takes Ca away from bones
-vit D needed to use Ca
-exercise uses Ca for bone formation
Calcium deficiency
-resembles Vit D deficiency
-may contribute to osteoporosis
-muscle cramps
-low-income kids
Calcium dietary sources
-dairy products
-nuts, beans, seeds, seaweed
Iron
-needed for O2, energy metabolism, cell proliferation, immune defence
-blood loss (menses) inc need
Iron homeostasis
-tightly regulated
-essential but also toxic
-free iron generates free radicals
-but sequested in cell by ferritin and transferrin in blood
iron deficiency
-anemia
Iodine
-make thyroid hormones
-fish and seaweed
-added to table salt
Iodine deficiency
-inland populations
-goiter and cretinism
Zinc
-needed for metalloenzymes and zinc finger proteins
Zinc deficiency
-poor growth and sexual development in children
-poor wound healing, dermatitis, impaired immune function
Copper
-required for many enzymes
-deficiency may cause anemia, bone demineralization, and blood vessel fragility
Selenium
-incorporated into 25 selenoproteins in humans
-contain selenocystein residues that are incorporated during translation
-selenocysyl-tRNA binds to UGA codons in mRNA w special seq in 3-untranslated region
-defieciency rare
