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Vitamins
Vitamins Definition: vital dietary substances
Not CHO, Protein, or Fat Necessary in very small quantities
to do special metabolic jobs Help regulate body processes
Especially B vitamins
Vitamins Cannot be made by body in
sufficient amounts Exception: Vitamin D
Supplied by food Most work by combining with
protein to form co-enzymes Natural vs. Synthetic
Rates of absorption different
Vitamins Provitamins
precursors to active vitamin Antivitamins
antagonists Avitaminosis
deficiency Hypervitaminosis
too much
Vitamins
Grouped by solubility. Fat soluble I
A D E K H20 soluble
B complex C B12 folate pantothenic acid biotin
Fat Soluble Absorbed in lymphatic system Deficiencies occur with fat
malabsorption Attached to protein carriers Not excreted, stored if not needed Can be toxic
Water Soluble Vitamins Absorbed directly through
intestinal wall Filtered by kidneys and excreted
if excess Tissues able to hold limited amounts May be able to become toxic Function as coenzymes for
production of energy
Vitamins Megadose
more than 10 X RDA Up to 35% of Americans take
vitamin supplements Food best source Supplements needed when diet
inadequate or during times of stress
Vitamin A Generic term for several compounds
retinal retinol retinaldehyde retinoic acid
Vitamin A Preformed vitamin A = retinol
found only in animal sources or fortified foods
6-12 months supply in body stores deplete in infectious disease major transport and storage form
• retinol binding protein picks up retinol from liver, carries it in blood
Vitamin A Provitamin A Beta carotene Plant source Supplies 2/3 Vitamin A necessary Converted retinal retinol Extremely effective antioxidant
Vitamin A Maintains cornea Helps with light
detection at retina Maintains integrity
of epithelial cells Fights infection
Supports normal bone and body growth
Reproduction Cell development
Vitamin A Deficiencies Epithelial cells flatten and harden
from production of keratin Drying & hardening of cornea
xerosis Xerophthalmia-
night blindness hardening of cornea complete blindness
Vitamin A Deficiencies Mucous linings harden
increased tendency for infection Skin Dry, rough, scaly “toad’s skin” Follicular hyperkeratosis Delayed sexual maturation/sterility
Vitamin A Toxicity Acne medication
can cause birth defects Overdosing
can cause birth defects joint pains loss of hair jaundice death
Vitamin A Sources Liver Fish Liver Oils Whole and
Fortified milk and dairy products
Dark green and yellow-orange vegetables
Vitamin D Made in body with help of
ultraviolet rays prohormone = calcitriol
Works in harmony with parathyroid hormone withdraws Ca++ from bone to maintain
Ca++ calcitonin decreases bone withdrawal
Vitamin D Liver manufactures precursor Migrates to skin-converted to #2
precursor with ultraviolet rays Liver and kidney convert #2
to active vitamin Absorption in small intestine Requires presence of bile salts
Vitamin D Associated with Ca++ and Po4-3
metabolism Promotes normal bone
mineralization Basic cell processes in brain &
kidney, liver, skin, reproduction Immune system
Vitamin D Deficiencies Bones fail to calcify Rickets or osteomalacia
can develop Muscle spasms and pain Repeated pregnancies and periods
of lactation Little sun exposure
Vitamin D Toxicity Stored in adipose tissue Released slowly Bone pain & weakness Calcium deposits in heart or lungs Increased serum calcium
Kidney stones Most toxic of all vitamins
Vitamin D Sources Fortified milk Fortified margarine Fortified breakfast
cereals Small amounts in
egg yolk, salmon, tuna fish
Vitamin E Generic name for 8 naturally
occurring fat soluble nutrients called tocopherols
Absorbed with aid of pancreatic secretions and bile salts
Stored in adipose tissue
Vitamin E Great antioxidant
Neutralizes free radicals Works with selenium to destroy
cell peroxides Protects lung from air pollutants Protects RBC Research on Vitamin E role in
decreasing heart disease
Vitamin E Decreased # of sickle cells Helps in cystic fibrosis Benefit in boosting immune function
and fighting Alzheimer’s
Vitamin E Deficiencies RBC break open Erythrocyte hemolysis in
premature infants (hemolytic anemia)
Affects vision Neurology problems
Vitamin E Toxicity Interferes with blood clotting action
of Vitamin K leads to hemorrhage with anticoagulant
drugs MYTHS:
improves athletic skill enhances sexual performance prevents wrinkling or gray hair
Vitamin E Sources Vegetable oils Milk Eggs Fish Cereal grains
Vitamin K Phylloquinone Essential for
synthesis of 5 proteins involved in blood clotting
Involved with CA++ in bone development
Vitamin K Absorbed in small intestine Needs bile salts for absorption Stored in liver Small amount-10 days supply Can be synthesized in intestinal tract
from dietary sources
Vitamin K Deficiencies Needed daily Extended use of antibiotics Malabsorption -defects in fat
absorption In sterile digestive tract in newborns
Hemorrhage Disease of newborns
Vitamin K Toxicity Red cell hemolysis Jaundice Brain damage
Vitamin K Sources Green leafy
vegetables Liver Milk Meats Egg yolk
Vitamin C Absorbed from small intestine ~ 3 months for deficiencies to
appear Antioxidant Collagen, connective tissue Removes Fe++ from ferritin,
activates folate
Vitamin C Important in wound healing Antihistamine effect Depleted in
Infectious processes Smokers Burns Surgery
How much to supplement unknown
Vitamin C Megadosing can cause hyperosmolar
diarrhea Rebound scurvy or rash when
large doses stopped quickly Fe++ overload
Vitamin C Supplemented in patients with
skin ulcers• along with vitamin C, vitamin A, zinc
spinal cord injuries• increase acid in urine
Vitamin C Deficiencies Scurvy- bleeding gums Pinpoint hemorrhages under skin Rough, brown scaly skin Massive bleeding into joints,body
cavities
Vitamin C Sources Citrus fruits Potatoes Broccoli Tomatoes Green peppers
Vitamin B1 Thiamin Combined with PO4 in jejunal
mucosa forms TPP
acts in process that converts pyruvate to acetyl CoA energy
Vitamin B1 Deficiencies Anorexia Severe constipation Lower HCL acid secretion General apathy & fatigue Severe: beriberi
paralysis and cardiac failure lower extremity edema muscle pain
Vitamin B1 Give thiamin to ETOH abusers Supplement in:
chronic illness gestation lactation strange diets
Vitamin B1 Sources Lean meats Liver Whole or enriched
grains
Vitamin B2 Riboflavin Facilitates energy production 2 enzymes operate at vital reaction
points of citric acid cycle De-amination of A2
Light sensitive, destroyed ultraviolet rays and fluorescent light
Vitamin B2 Deficiencies Tissue inflammation/breakdown Delayed wound healing Characteristic cracks at corners of
mouth-cleilosis Tongue becomes red swollen -
glossitis Eyes burn, itch, tear
Vitamin B2 Deficiencies Scaly, greasy skin-seborrheic
dermatitis in skin folds Supplement in GI diseases,
pregnancy, and lactation
Vitamin B2 Sources Milk Meat Whole
grain/enriched breads
Dark green leafy vegetables
Niacin Participates in energy metabolism Small amount made from tryptophan Active in citric acid cycle Used in CVD to lower CHOL Acts as vasodilator-causes skin
flushing Can injure liver
Niacin Deficiencies Weakness and anorexia Skin eruptions Dark scaly dermatitis Severe-confusion, pellagra 4 D’s = dermatitis, diarrhea,
dementia, death
Niacin Sources Peanuts Beans Peas Enriched grains
Vitamin B6 Pyridoxine Sensitive to light Part of coenzyme in protein
metabolism Converts tryptophan to serotonin Stimulated cerebral activity and
brain metabolism (gray matter) Hemoglobin synthesis
Vitamin B6 Deficiencies Greasy, scaly dermatitis Microcytic anemia Abnormal EEG Infant seizures Isoniazid TX Supplements TB rx, pregnancy and
oral contraceptives
Vitamin B6 Toxicity Large doses for treatment of PMS Lack of muscle co-ordination and
numbness
Vitamin B6 Sources Peanuts Fish Poultry Meat Bananas Enriched whole
grains
Folate or folacin Part of building blocks of DNA/RNA Helps from heme in hemoglobin Increased needs in
periods of accelerated growth Etoh or drug abuse
Folate Deficiencies Neural tube birth defects Oral contraceptive use Some anti-convulsant use GI disease including diarrhea Megaloblastic anemia Food processing can destroy vitamin
Folate Sources Enriched cereals Green leafy
vegetables Liver Milk Eggs Dried beans &
peas
Vitamin B12 Cobalmin Bound in stomach by specific
glycoprotein called intrinsic factor Pernicious anemia Folate and B12 work together in cell
division True dietary deficiency only seen in
vegans
Vitamin B12 Post-gastrectomy anemia IM injections
Vitamin B12 Sources Liver Fresh Shrimp Meats Milk Eggs Cheese
Pantothenic Acid Component of tissue enzyme CoA No deficiency or toxicity Supplements not usually needed Lots of jobs:
synthesis of lipids neurotransmitters steroid hormones hemoglobin
Biotin No deficiency except long term TPN No toxicity Partner with acetyl CoA Synthesis fatty acids and A2
Supplement not usually needed
Vitamin Supplements In most cases, eat the food is the
best recommendation. Interactions between high doses of
vitamins not known. Long-term risks not known
Apoptosis
A GOOD Idea The elderly Finicky eaters Very-low kcal diets Smokers and Alcoholics Pregnant and lactating women Certain
diseases/trauma/malabsorption