Vitamins Organic substancesderived from living matter and
contain carbon Small amounts required for normal metabolism,
growth, and maintenance Coenzymes (substances that activate
enzymes) and regulators of metabolic processes Do not provide
energy Do not become part of body structure Specific functions
nontransferable deficiency diseases
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Vitamin Classifications Fat soluble (A, D, E, and K)more stable
to environmental influences; absorbed with fat; stored in body
Water soluble (B vitamins and C) less stable to environmental
influences; only B 12 stored for any length of time
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Vitamin A Chemical necessary for vision Health of epithelial
tissueskin, lining of gastrointestinal tract Normal bone growth
Metabolism of adipose tissue
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Vitamins A preformed vitamin is already in a complete state in
ingested foods A provitamin requires conversion in the body to
become complete. A provitamin is also called a precursor because it
is a substance from which another substance is derived
Vitamin A Deficiency Diseases Night blindness Xerophthalmia -
Extreme dryness and thickening of the conjunctiva, often resulting
from a deficiency of vitamin A In developed countries, disease or
lack of treatments can cause deficiencies
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Vitamin A Deficiency Vitamin A deficiency diseases in addition
to vision: Vitamin A deficiency diseases in addition to vision:
Anorexia Anorexia Growth retardation Growth retardation Increased
susceptibility to infection Increased susceptibility to infection
Disorders of the skin and hair follicles Disorders of the skin and
hair follicles Taste impairment Taste impairment Balance
disturbances Balance disturbances Bone changes that impinge on
cranial nerves (increased osteoblastic activity) Bone changes that
impinge on cranial nerves (increased osteoblastic activity)
Increased intracranial pressure Increased intracranial pressure
Fertility Fertility
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Prevention and Treatment of Vitamin A Deficiency in Developing
Countries Prevention Breastfeeding Supplementation Food
fortification Diet diversification Treatment High-dose vitamin A
Active corneal disease is a medical emergency
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Vitamin A Toxicity Carotenemia - too many yellow vegetables;
(squash and carrots) usually benign Hypervitaminosis A - can be
fatal S/S similar to brain tumor Liver disease Additional
information: www.sightandlife.org
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Vitamin D Functions Increases intestinal absorption of calcium
and phosphorus Stimulates bone cells to build tissue Signals kidney
to return calcium to bloodstream, not excrete it in urine
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Vitamin D Deficiency Ricketsin children: still a risk,
especially to dark- skinned breastfed infants Osteomalaciain
adults: low D intake and/or little sun exposure can cause a bone
disease in adults analogous to rickets in children, marked by bone
demineralization caused by impaired metabolism or deficiency of
vitamin D or phosphorus.
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vitamin D excess Disorders due to vitamin D excess One of the
most likely vitamins to cause toxicity Loss of appetite
Nausea/vomiting Polyuria Muscle weakness Constipation More serious
issues consist of calcium deposits in the heart, kidneys, and
brain
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Vitamin D Sources Sunlight on skindaily sun exposure Arms,
shoulders, and back without sunscreen Between 11 a.m. and 2 p.m.
for 15 minutes in summer and 20 minutes in spring and fall
Fortified foodsmilk combines vitamin with calcium Supplementscod
liver oil vitamin/mineral supplement
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Vitamin E Functions Antioxidant - take on oxygen preventing
surrounding molecules from becoming unstable Protects cell
membranes (plays a role in vitamin E, provitamin A, and unsaturated
fatty acids stability In lungs, barrier against air pollution
Protects red blood cells from oxidation in lungs
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Vitamin E Deficiency Hemolytic anemia - Anemia resulting from
the lysis of red blood cells Degenerative neurological problems
Anemia in premature infants
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Vitamin E Toxicity Excessive supplemental vitamin E can cause
Gastrointestinal symptoms Muscle weakness Double vision Increased
bleeding tendencies
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Vitamin E Sources Vegetable oilscanola and olive oils highest
in alpha-tocopherol (one of the components of vitamin E and is
present in vegetable oils, nuts, and seeds or produced
synthetically. It is the predominant form of vitamin E in the human
body and in supplements.) Whole grains Especially fortified
ready-to-eat cereals Wheat germ Nuts Leafy vegetables
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Vitamin K Functions Blood clottingNecessary for the liver to
make prothrombin and other clotting factors Bone
metabolismFacilitates synthesis of a calcium-binding protein
(Osteocalcin)
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Vitamin K Note - Vitamin K can be given to serve as an antidote
for warfarin overdose
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Vitamin K Deficiency Bleeding problems can occur in Newborns
Long-term antibiotic therapy users People with malabsorption
syndromes
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Vitamin K Sources Intestinal synthesis Varies from person to
person Not sufficient as sole source Food sourcesgreen leafy
vegetables Broccoli, Brussels sprouts Cabbage, collards Salad
greens, spinach
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Vitamin K Toxicity Not from naturally occurring forms Vitamin
K1 (plants) Vitamin K2 (intestinal synthesis) Pharmaceutical K1
(phytonadione) not recommended intravenously except in emergency
due to life- threatening reactions
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Vitamin C Functions Collagen synthesisstrong, fibrous protein
in connective tissue Antioxidantmore sensitive to oxidation than
vitamins A and E Iron absorptionacts with HCl to keep iron in more
absorbable form Aids in the synthesis of norepinephrine and
serotonin
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Vitamin C Deficiency Signs and symptoms of scurvy Earlybleeding
gums, petechiae (small hemorrhage) Latedelayed or reversed wound
healing, bone pain and fractures, tooth loss, hemorrhage
Treatmentvitamin C Current cases of scurvy Due to restricted eating
patterns Delayed diagnosis due to low suspicion
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Vitamin C Sources Fruitscitrus, cantaloupe, kiwi fruit,
papayas, strawberries Vegetablesbroccoli, Brussels sprouts, green
and red peppers Boiling, cooking, and canning fruits and vegetables
lowers vitamin C content by 33%
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Vitamin C Toxicity S/Snausea, abdominal cramps, diarrhea
Megadoses contraindicated if at risk for Iron overload Kidney
stones
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Thiamin Functions Coenzyme in metabolism of : Carbohydrates
Glucose Branched chain amino acids
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Thiamin Deficiencies At risk Alcoholics People subsisting on
milled rice Lack of glucose for central nervous system Wernicke
encephalopathymotor and sensory deficits involving eye muscles,
balance, and memory Korsakoff psychosisamnesia and impaired
conceptual functions
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Thiamin Deficiencies Beriberi broad classification of thiamin
deficiency Dry beriberi muscle weakness Wet beriberi cardiovascular
system culminating in right-sided heart failure Infantile beriberi
loud cry and convulsions
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Thiamin Sources Meat/legumespork, black beans, black- eyed peas
Other plant sourceswheat germ, enriched grain products Fortified
foodscereals
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Riboflavin Function Coenzyme in metabolism of protein and other
vitamins Deficiency Usually combined with other vitamin
deficiencies like thiamin and niacin If alone its called
Ariboflavinosis
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Niacin Functioncoenzyme in energy metabolism Deficiencypellagra
3 Dsdermatitis (glove), diarrhea, dementia 4th Ddeath Sources of
niacinmeat; fish; poultry; whole, enriched, or fortified grains;
coffee; tea
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Vitamin B6 Functioncoenzyme in the metabolism of amino acids
Deficiencyrare except for drug interactions and food-processing
errors
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Vitamin B6 Sources and Toxicity Sources of vitamin B6widely
distributed in foods, especially fortified beverages and cereals
Toxicity None reported from foods
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Folate/Folic Acid Functionsnecessary for the formation of DNA,
thus participates in the reproduction of every cell Deficiency Link
to neural tube defects (NTDs) - A group of birth defects that
affect the backbone and sometimes the spinal chord. Discovery of
this led to recent change in enrichment of grains Megaloblastic
anemia
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Folate/Folic Acid Sources and Toxicity Sources of folate Liver,
dried peas, beans, lentils Green leafy vegetables Fortified grains
Toxicity of folic acid None reported from food or supplement s
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Vitamin B12 Function and Deficiencies FunctionsRequired for
Synthesis of DNA, RNA Metabolism of amino acids and fatty acids
Synthesis and maintenance of myelin Deficiency Other
pathologygastric resection, gastric atrophy, Crohns disease Dietary
causeselimination of animal products
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Wise Use of Supplements Select a multivitamin/multimineral
preparation Take recommended dosages, not to exceed 150% (one and
one-half times) the RDA Mention when asked medication history