Vitamins. Definition: vital dietary substances Not CHO, Protein, or Fat Necessary in very small...

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