Thiamin (B1)

Metabolized to:

Functions:

Hypovitaminosis:

Sources:

coenzyme thiamin pyrophosphate

functions in TCA cycle, glucose metabolism, and nerve impulses

severe hypovit: Beriberi polished rice syndrome (neuromuscular symptoms)

Moderate hypovit: Wernicke Korshakoff Syndrome in chronic alcoholics

meats, grains, legumes

Riboflavin (B2)

Metabolized to:

Function:

Hypovitaminosis

Sources:

coenzymes FAD and FMN

function in redox

hypovit: rare, angular cheilitis, glossitis, and scaly dermatitis

milk, eggs, leafy veggies

Niacin (B3 nicotinic acid)

metabolized to:

function:

hypovitaminosis:

sources:

pharmalogical effects:

coenzymes NAD and NADP

redox

hypovit: pellagra (2 D's dermatitis, diarrhea, and dementia)

meats and grains

in pharm doses will decrease fatty acid mobilization from adipose tissue and decrease levels of cholesterol. Used to attenuate hyperlipidemias

Pyridoxine (B6)

metabolized to:

functions:

hypovitaminosis

sources:

coenzyme pyridoxal phosphate

functions in pathways that involve neurotransmitter metabolism, heme biosynthesis, converts typtophan to niacin

hypovit: rare, peripheral neuropathy, sideroblastic anemia

early deficiency: lethargy, irritability, nervousness, deperssion

women taking birth control should double

meats, grains

Pantothenic Acid

Metabolized to:

Function:

Hypovitaminosis:

sources:

coenzyme A and phosphopantotheine

functions in coenzymes and as CoA for acyl transfers

hypovit: NONE!

liver, egg, milk

Biotin

Metabolism

Function

Hypovitaminosis

Fun Facts

linked to lysine but can exist free. Digestion of protein+biotin = biocytin which is hydrolyzed into free biotin

functions in carboxylation reactions

hypovit rare and only experimentally induced

avidin binds biotin so it cant be absorbed, intestinal flora produce half of daily supply

B12

Metabolism

Function

hypovitaminosis

sources

active forms = adenosyl cobalamin, methyl cobalamin

ingested form = hydroxy-cobalamin, OTC = cyano-cobalamin (ingested forms metabolized into active forms)

only required by 2 metabolic pathways (homocysteine -> methionine and methylmalonyl -> succinyl CoA)

neurological damage, megalobastic anemia, pernicious anemia (cause = lack of intrinsic factor)

sources: Not Plants!

Folic Acid

Metabolism

Function

Hypovitaminosis

sources

can only absorb monoglutamate form. After transport into cells its turned into polyglutamated form (most active as coenzyme). Poly form reduced to tetrahydro form

tetrahydro functions as one carbon transfer agent

hypovit = macrocytic anemia (low hemoglobin and large RBC)

leafy veggies, liver, cereal, nuts, legumes

Vitamin C

metabolism

functions

hypovitaminosis

sources

active as ingested

hydroxylation of collagen, iron absorption, antioxidant, prevent senile cataracts

scurvy

citrus, veggies, potatoes

Vitamin A

metabolism

functions

hypovitaminosis

sources

consumed as B-carotene, cleaved into retinal <-> retinol. Retinal -> retinoic acid (all trans) -> 11-cis-retinal

vision, gene regulation, antioxidant

keeps epithelial cells from keratinizing

severe hypovit: keratinization of the cornea

mild: night blindness

liver, dark green and yellow veggies

Vitamin D

metabolism

function

hypovitaminosis

sources

light converts 7 dehydrocholesterol -> cholecalciferol(D3)

Then converted into active form by hydroxylation in liver then kidney

induces synthesis of protein for Ca absorption, acts with PTH to promote bone reabsorption, inhibit Ca excretion in kidneys, Ca homeostasis

rickets, osteomalacia

sunlight, liver, egg, fortified foods

Vitamin E

metabolism

function

hypovitaminosis

sources

only alpha form meets human needs, liver resecretes only alpha tocopherol

antioxidant

increases fagility of RBC membranes

veggie oils, widespread

Vitamin K

Metabolism

Function

hypovitaminosis

sources

pharmalogical uses

metabolism: ???

functions as cofactor in carboxylation of precoagulation factors and bone proteins

hemorrhage

intestinal flora produce half, widespread in foods

counteract overdose of anticoagulents, when broad spectrum antibiotic therapy is used

Iron

Functions

Special Requirements

Absorption (enhancers + inhibitors)

Evaluation of iron status

constituent of proteins in transport and metabolsim on oxygen

newborns: need least

pregnant women: need most

Absorbed as heme or as Fe+2. Stored as ferritin.

Enhancer: vitamin C, organic acids

inhibitors: calcium, carbonates

most sensitive: marrow iron, serum ferritin, %saturation

least sensitive: hemoglobin

Involved in iron homeostasis, binding to ferroportin promotes internalization of the complex and its degradation

keeps iron from being released into the blood stream

Iron Disorders

signs and symptoms

genetic disorders

pallor, fatigue, poor exercise tolerance, psychomotor development impairment in infants

hereditary hemochromatosis - intestinal absorption of iron is increased

Calcium

functions

homeostasis

disorders + causes

component of mineralized tissue, muscle contraction, cell signaling, hemostasis

homeostasis maintained by PTH, vitamin D, and calcitonin

About half bound to albumin other half is free (and biologically active)

Hypercalcemia - caused by hyperparathyroidism and cancer

Hypocalcemia - hypoparathyroidism

rickets

Magnesium

Functions

Deficiency

Toxicity

Found in bone and teeth, charge neutralization, enzymes bind to induce activation or stablized conformation.

Only occurs secondary to another disease, symptoms non specific

Due to excessive intake of magnesium salts (antacids, laxatives), symptoms non specific

Zinc

Functions

dietary sources

homeostasis

deficiency and toxicity

growth and reproduction, wound healing, taste, and immune function, stabilization of biomembranes

shellfish, red meats, correlated with protein intake

When intake is high, metallothionein synthesis is induced

When intake is low, less metallothionein

Patients on anticonvulsants, pregnant women, elderly patient, and people with malabsorption syndromes at risk

Copper

Functions

Absoption and transport

deficiency and toxicity

important in erythropoiesis, RBC function, cholesterol and lipoprotein metabolism, cardiac function, and immune function

when intake is low, absorption is increased

transported bound to albumin to the liver for incorporation into proteins

Menkes disease results in severe deficiency

Wilsons diease occurs from toxicity - Chelation therapy can be effective

Selenium

functions

antioxidant detoxification of peroxides, thyroid metabolism, and regulation of redox status

incorporated cotranslationallly in the form of selenocysteine