vitamins and vitamin E

thiamin DRI

1.2mg/day for men -1.1mg/day for women

vitamin E DRI

15mg/day as alpha tocopherol -increased requirement w/ PUFA intake ---vit c and Se may spare vit E

thiamin function

CHO metab (Krebs) and serves as coenzyme in decarboxylation of: ---alpha-ketoglutarate to succinyl CoA ---Pyruvate to acetyl CoA -BCAA metab -synthesis of pentose and NADPH -membrane and nerve conduction

vitamin A delivery

delivery to target tissue is dependent on the synthesis of Retinol Binding Protein (RBP) --each mole of retinol combines w/ 1 mole of RBP to form holo-RBP --in plasma, holo-RBP interacts w/ transthyretin (TTR--formally known as prealbumin) -RBP-TTR complex is circulating form in plasma, from which retinol will be delivered into a target tissue ---Apo-RBP and TTR will be released

primary vitamin K deficiency

due to insufficient intake usually not seen in normal conditions

infantile beriberi

during first 2-4 months -in infants breast-fed by thiamine deficient mothers

B vitamins

Thiamin (B1) Riboflavin (B2) Niacin (B3) Adenine (B4) Panthotenic acid (B5) Pyridoxine (B6) Biotin (B7) Inositol (B8) Folate (B9) Para-aminobenzoic acid (PABA-B10) Folic Acid (B11, new name for folate) Cobalamin (B12)

cerebral beriberi

Wernicke Korsakoff syndrome in chronic alcoholics -first stage: Korsakoff psychosis. Mental confusion, inability to speak, dementia -second and last stage: Wernicke's encephalopathy. Ophtalmoplegia (eye nerve paralysis), nystagmus (eye rolling). Ataxia, coma, death ----this stage is medical emergency

breath pentane measurement

functional test -pentane is a product of linoleic and linolenic acids peroxidation and is exhaled through the lungs ---when vit E is low, pentane exhalation is high

erythrocyte hemolysis

functional test -shorter life of RBC in vit E deficiency ---lacks specificity

criteria of vitamins

group of organic compounds that are micronutrients, not macro -present as natural components in small amounts of food -not synthesized by the host in the amounts to meet normal physiological processes -essential for normal physiological functions -absence/deficiency or underutilization cause specific deficiency syndrome

tocopherol

have saturated side chain -alpha and beta tocopherol have highest bioactivity

tocotrienol

have unsaturated side chain -much lower bioactivity

vitamin A toxicity

amounts greater than 10x RDA -anorexia, dry, itchy skin, alopecia, ataxia, liver and spleen problems -beta-carotene ingestion does not pose serious side effects except yellow discoloration of the skin

four vital amines

antiberiberi, antiscurvy, antirickets, and antipellagra

secondary deficiency and newborns

hemorrhagic disease of newborn due to: -lipids and fat soluble vit poorly transferred through placenta -liver synthesis of blood clotting factors starts after several months -human milk is sterile and not good source of vit K -infant gut is sterile

thiamin deficiency

high risk groups include alcoholics, elderly, pts w/ TPN, raw-fish consumers, refined rice consumes -symptoms of depression, weakness, loss of appetite/weight, followed by cardiovascular and neurological symptoms

synthesis of pentoses and NADPH (thiamin)

in hexose monophosphate shunt --pathway in which sugars of various lengths are interconverted and pentoses are generated for nucleic acids syntheses

secondary vitamin K deficiency

induced by some disease or drug therapy --malabsorption of fat including biliary obstruction or steatorrhea -liver disease to the inability to use it for synthesis of coagulation factors -drugs: antibiotics as they wipe of intestinal flora, anticoagulants like warfarin, heparin. These are blood thinners -megadoses of vit A or E

vitamin A and cancer/heart disease risk

inverse relationship bw the level of consumption of provitamins A in fruits and veg and CVD, cancer and stroke -cancer patient tend to have low serum levels of beta-carotene

phylloquinone (K1)

isolated from plants (dark-green leafy veggies, the greener the better soruce) -tobacco has highest amount per unit weight and when its smoked a small amount of vit K is volatilized and absorbed -contain functional naphthoquinone ring and aliphatic side chain -contain phytyl side chain

bitot's spots

keratinization of cornea -localized spots

vitamin E functions continued

protective effects in atherogenesis (besides prevention of lipid oxidation) --inhibits platelet and other monocyte adhesions and aggregation -maintenance of normal reproductive systems -may be anticarcenogenic

anticoagulant factors

proteins C, S, Z -protein C=serves as brake on the speed of the intrinsic cascade, as feedback loop -Protein S=enhances the activity of protein C -Protein Z fxn is unknown

vitamin K toxicity

rare, might occur in infants when supplemented w/ menadione -results in hyperbilirubinemia and jaundice

vitamin A

refers to group of metabolites --retinoids active vitamins -carotenoids==provitamins A

vitamin K functions

regulates the synthesis of clotting proteins -procoagulant factors and anticoagulant factors -all factors and proteins in blood clotting are synthesized in liver by carboxylation and contain gamma carboxyglutamate (Gla) residues -vit K is necessary for conversion of protein-bound glutamate residues into gamma carboxyglutamate residues (Gla)

fat soluble vitamins

require fat for absorption and transport -follow lipids for entry/exit out of intestinal cells -transported via chylomicrons and other lipoproteins to target tissues -stored in body in appreciable amounts -deficiency less common in US -toxicity more common than w/ water soluble vitamins

animal form of vit A

retinoid -in egg yolks, butter, whole milk products, liver, fish oils

supplemental form of vit A

retinyl palmitate, I-carotene -in US, low fat dairy products, some juices, and breakfast cereals are supplemented (~500 IU/serving) -supplements may contain from 3000 to 25000 IU/tablet ---RDA 5000 IU/day

vitamin A assessment for nutriture

serum retinol--insensitive to early deficiency and nonspecific -serum carotenoids (reflect immediate dietary intakes) -Relative dose response

water soluble (vitamins) characteristics

vitamin C, B vitamins -required in miniscule amounts, not stored in body in appreciable amounts, excreted in urine when plasma levels are high, unlikely to be toxic except in mega doses, and most are involved in energy metabolism

functional tests for vitamin K status

bleeding time: lancet stab, blood clot w/in 5 min -clotting time: collected venous blood requires 6-10 min to clot -prothrombin time (PT): time required for fibrin to form (measures factor II). Normal is 11-13 sec, issue if more than 25 -partial thromboplastin time (PTT): measures clotting factors. Serum is treated w/ activiated thromboplastin and clotting time is recorded -serum prothrombin conc -platelet count

thiamin in body

body contains 30 mg of thiamin, half in muscle and half in other organs and tissues -excreted in urine in either free or metabolized forms: -4-methylthiazole-5acetic acid -2-methyl-4-amino-5-pyrimidine carboxylic acid

vitamin A antioxidant

both vitamin A and carotenoids sequester free radicals, but carotenoids are more potent -beta-carotene, lutein, lycopene

vitamin K food soruces

broccoli=150-200ug spinach=300-400ug parsley=500-600ug margarine=20-150ug egg yolk/liver=100-150ug potatoes=1ug

carotenoids reaching liver

carotenoids can either: 1) small portion may be cleaved to form retinol 2) some may be incorporated into VLDL synthesized in the liver 3) some can be stored in the liver

vitamin A functions cont

cellular differentiation (retinoic acid) -growth (retinoic acid, retinol) -fertility (retinol) -immunity (retinoid/carotenoids) -skin integrity (retinoic acid) -bone development (all forms) -gene expression and cell development -needed by epithelial cells in lungs, trachea, skin, and GI

history of vitamins

certain diseases were related to foods/their deficiency: -scurvy: eating lemons -night blindness: eating liver -Beriberi: associated w/ eating polished rice -Pellagra: associated w/ eating corn -Rickets: treated w/ liver oil

vitamin A deficiency

common in developing countries -night blindness, retarded growth, anorexia, increased susceptibility to infection, keratinization of mucous membranes of respiratory, alimentary, urinary tracts, skin, and epithelium of eye

assessing vitamin E status

-serum tocopherol conc -tocopherol levels in adipose tissue and RBC -erythrocyte hemolysis -breath pentane measurement

conversion factors for vit A metabolites

1 retinol activity enquivalent (RAE)=1 ug retinol; 12 ug Beta carotene, and 24ug other provitamin A carotenoids

vitamin E (Tocopherol)

8 different "vitamers" -two groups of 4 isomers: alpha, beta, gamma, delta -tocopherol and tocitrienols

Vitamin K DRI

90mg/day and 120mg/day for adult men/women

Thiamin deficiency

RBC transketolase which is enzyme involved in hexose monophosphate shunt -24 hr urinary excretion of thiamin or its metabolites -thiamin load test --involves giving 5mg oral dose of thiamin ----if urinary thiamin excretion is less than 20ug, indicates deficiency

vitamin E deficiency

True deficiency is rare -occurs in 3 situations: 1) ppl cannot absorb dietary fat 2) premature, low birth weight infants. <1500grams or 3.5lb 3) rare disorders of fat metabolism

membrane and nerve conduction (thiamin)

aberrations in nerve fxn may be due to lack of energy -could regulate nerve impulse transmission by phosphorylation/dephosphorylation

vitamin E absorption/storage

absorbed as free form and follows lipids in entry/exit out of intestine and transported as lipids -stored mostly in adipose tissue and some in liver

vitamin A absorption

absorption and transport follows that of lipids -retinoid absorption: 70-90% -carotenoids: 20-50%(decrease intake, increase absorption)

Vitamin A RDA

adult women: 700 RAE adult men: 900 RAE or ~5000IU

vitamin E synthesized

all metabolites are synthesized in plants, especially rich in seeds, bran, and germ sections of plants -oils are best sources. In food, 75%=alpha tocopherol, 20%=beta tocopherol, and 5%=alpha tocotrienol -found in fatty tissues in animals and is inferior source compared to plants

vitamin E functions

antioxidant and maintains membrane integrity -not only in cell membranes, also w/in cell (mitochrondria, ER) --terminates chain-propagation rxn involving lipid peroxyl radicals (provides H from its C-6 hydroxyl group) --in process, Vit E is oxidized (tocopherol radical) and must be regenerated ----requires vit C, glutathione, and NADP

vegetable form of vit A

carotenoids -in green, red, orange, and yellow veggies -more than 600 forms: 50 are known to have vit A fxn

vitamin A digestion

carotenoids and/or retinyl esters are bound to protein and hydrolysis occurs w/ pepsin and other proteolitic enzymes (lipases, esterases) -after being released, these retinoids and carotenoids are solubilized into micellar soln and diffuse through mucosal cells into lymph

BCAA metabolism (thiamin)

decarboxylation of branched-chain alpha-keto acids that arise from valine, isoleucine, and leucine

hematopoietic b vitamins

folic acid, vitamin B12, vitamin B6, and pantothenic acid

wet beriberi

edematous -heart enlargement, arrhythmias, hypertension -Na and water retention--edemia ----excessive CHO loads and strenuous exercise could result in this type

excessive Vitamin A intake

elderly in jeopardy--diminished liver clearance -leads to bone abnormalities and increased susceptibility for fractures

B complex vitamins

energy releasing, hematopoietic, and other

vitamin A functions

essential for vision and systemic fxns -cellular differentiation -growth/reproduction -bone development -immune system

procoagulant factors

factors II (prothrombin), VII, IX, and X -all help in blood clotting

Thiamin

first discovered vitamin in 1897 -in 1912, found it to be an amine and essential for life, therefore vital amine, or VITAMINE

other b vitamins

vitamin B6, thiamin, folic acid, vitamin B12, and niacin (B3)

osteocalcin (vit K function)

marker of bone turnover -small protein containing 3 Gla residues per molecule -synthesized by osteoblasts. When made, 70-80% is bound to hydroxyapatite and rest stays in circulation -binds to hydroxyapatite -patients w/ osteoporosis, circulating osteocalcin is undercarboxylated -high levels and low serum vit K are associated w/ lower BMD and higher risk for fractures

relative dose response (RDR)

measures vit A stores in liver -detects DBP released from liver --first measure of fasting plasma retinol --give oral dose of vit A -measure plasma retinol 5 h later ----if stores are depleted, plasma retinol will markedly increase after 5 hours, due to its binding to apo-RBP in liver and then released as holo-RBP

prolonged thiamin deficiency

mental confusion, ataxia, peripheral paralysis ophtalmophlegia (eye muscle), tachycardia -leads to BERIBERI

thiamin absorption and metabolism

must be free (not phosphorylated) to be absorbed -active transport (low conc) -passive transport (high conc) -thiamin in blood is usually in the monophosphate form (TMP) and bound to albumin for further transport ---free thiamin can be phosphorylated in liver or other tissues

serum tocopherol concentration

need to calculate ratio: vit E/total lipids (>0.6 is adequate) -more lipids consumed, higher the conc

target organs for Vit E

neuromuscular, vascular, and reproductive -deficiency is related to the lack of antioxidant leading to cell damage

vitamin E toxicity

one of the least toxic and at high doses may antagonize the utilization of other fat soluble vitamins

extrahepatic Gla proteins associated with calcified tissues

osteocalcin and matrix-gla protein (synthesized by osteoblasts in bone) -plaque Gla-protein (in artherosclerotic plaques) -others--isolated from renal stones and urine

Population at risk for vit E deficiency

people w/ fat malabsorption ---cystic fibrosis and other hepatobiliary disorders -premature, low birth infants ---limited transplacental movement

vitamin A deficiency risk

people w/ malabsortive disorders: steatorrhea, pancreatic, liver or gallbladder disease, intestinal parasites ---in alcoholics, celiac disease, cystic fibrosis, and other intestinal probllems -premature babies (low liver storage)

dry beriberi

peripheral neuropathy -loss of sensory, motor and reflex function in periphery -tingling, numbness, burning sensation of feet -muscle wasting

vitamin K

phylloquinone, menaquinone, and menadione -all three are active -mostly stored in liver, although body pool is small for fat soluble vitamins (50-100ug)

fat soluble

soluble in fat and fat solvents, excess intake stored in body, small amounts excreted in bile, deficiency syndrome slow to develop, -not absolutely necessary in diet every day -absorbed into lymphatic system and follow lipid transport -some have precursors or provitamins -needed by higher organisms -may be toxic at low levels (6 to 10 times RDA)

water soluble

soluble in water, minimal storage of dietary excess, excreted in urine, deficiency symptoms may develop rapidly -needed in everyday diet -absorbed into blood via portal vein -do not have precursors -needed by both simple and complex -toxic at megadose (>10 times RDA)

menaquinone (K2)

synthesized by gut bacteria (in colon) and usually available for absorption by host ---may provide up to 50% of total -contain functional naphthoquinone ring and aliphatic side chain -side chain is composed of varying number of isoprenoid residues

menadione (K3)

synthetic form

energy releasing b vitamins

thiamin (B1), riboflavin (B2), Niacin (B3), Pantothenic acid, biotin, and vitamin B6

thiamin

thiamin pyrophosphate (TPP), also called thiamin diphosphate (TDP) AND thiamin triphosphate (TTP)

thiamin sources

ubiquitous in small amounts in all foods and not destroyed by regular cooking -liver/yeast is highest amount -whole or enriched grain products and cereals, meats (pork), and legumes are best sources -rice and refined products are poorest sources -enzyme thiaminase is present in raw fish or tannic and caffeic acids destroy about 50% of thiamin

thiamin toxicity

usually doesn't occur w/ oral doses (500mg/d for 1 month) -may occur w/ parenteral, intravenous or intramuscular route (100x rec) ---headache, convulsions, cardiac arrhythmia