NR 228 Exam 2 Review Latest 2023 / 2024
Week 4 Outline: Chapters 7. 8. And 17
What are vitamins?• Organic molecules needed in very small amounts for cellular metabolism • Perform specific metabolic functions
Water Soluble Vitamins
- Dissolve in water & are readily available
- Not stored in our body
- Excess water-soluble vitamins are quickly excreted in urine. They do not accumulate and
- Vitamin C taken in excess can cause diarrhea
become toxic
Vitamin B1 (thiamine) ❖ Use: helps to release energy from foods and is important in maintaining nervous system function
❖ RDA: men = 1.2 mg; women = 1.1 mg
❖ Source: lean pork, whole or enriched grains and flours, legumes, seeds, nuts ❖ Deficiency
❖ Risk factors
- Ataxia (muscle weakness/loss of coordination) and tachycardia
(rapid heartbeat)
o Wernicke-Korsakoff syndrome: a cerebral form
o Marginal: psychologic disturbances, headache, fatigue,
irritability
- Alcoholism, renal dialysis, parenteral nutrition, human
immunodeficiency virus / acquired immunodeficiency syndrome (HIV/AIDS), persistent vomiting (as in hyperemesis gravidarum), anorexia nervosa, gastrectomy
❖ Toxicity: nontoxic
Vitamin B2 (riboflavin)
❖ Use: promotes vision and healthy skin, converts amino acid tryptophan into
niacin 1 / 3
❖ RDA: men = 1.3 mg; women = 1.1 mg
❖ Source: milk, enriched grains and cereals, whole grains, vegetables, dairy, meats, fish, poultry, eggs
❖ Deficiency:
- Ariboflavinosis (sores in the mouth)
- Cheilosis, glossitis, seborrheic dermatitis
❖ Toxicity: nontoxic
Vitamin B3 (niacin) ❖ Use: aids in digestion, metabolism, and normal enzyme function, healthy skin and nerves
❖ RDA: men = 16 mg; women = 14 mg
❖ Source: protein-containing foods (meats, poultry, fish, legumes, enriched cereals, milk, coffee, tea
❖ Deficiency:
The 3 Ds:
o Diarrhea: Gastrointestinal (GI) tract damage alters digestion,
absorption, and excretion, which leads to glossitis, vomiting, and diarrhea.
o Dermatitis: only on skin exposed to sun.
o Dementia: In severe deficiencies, confusion, anxiety, insomnia,
and paranoia develop ❖ Risk factors
❖ Toxicity:
- Alcoholism, malabsorption
- vasodilation and flushing effect
- Monitor to prevent liver damage, gout, and arthritis
Vitamin B6 (pyridoxine) ❖ Use: aids in protein metabolism and the production of red blood cell, insulin, and hemoglobin
❖ RDA: adults = 1.3 mg
❖ Source: widespread in foods, especially whole grains and cereals, legumes,
chicken, fish, pork, eggs
❖ Deficiency:
- Related to low intakes of all B vitamins
- Some drugs affecting the bioavailability and metabolism of
pyridoxine: oral contraceptives, isoniazid, penicillamine,
cycloserine, hydralazine 2 / 3
❖ Risk factors
- Alcoholism, malabsorption
❖ Toxicity: UL of 100 mg/day
- Megadose supplementation may cause ataxia and sensory
neuropathy
Folate (folic acid) ❖ Use: aids in protein metabolism and red blood cell formation and may reduce the risk of neural tube birth defects
❖ RDA: adults = 400 ug
❖ Source: leafy green vegetables, legumes, some fruits, fortified cereal grains
❖ Deficiency:
❖ Risk factors
- Results in megaloblastic anemia, glossitis, diarrhea, irritability,
absentmindedness, depression, anxiety
o Drug-nutrient interactions: anticonvulsants, oral contraceptives,
aspirin
- Risk with conditions that increase cell division, limited food
intake and variety, and chronic excessive alcohol ingestion
❖ Toxicity: UL of 1000 µg of folic acid
- Excess folate or folic acid intake not recommended or
warranted; may mask cobalamin deficiency
Vitamin B12 (cobalamin) ❖ Use: aids in the production of normal red blood cells as well as the maintenance of the nervous system
❖ RDA: adults = 2.4 ug
❖ Source: only animal-derived foods (meat, fish, poultry, eggs, dairy); Vegans must supplement or use fortified products
❖ Deficiency:
- Usually secondary
- Results in megaloblastic anemia or pernicious anemia
- Additional neurologic or neuropsychiatric effects
- Older adults at risk
- May be masked by folate levels
❖ Toxicity: unkown
Vitamin C (ascorbic acid)
❖ Use: iron absorption and collagen synthesis, aids in wound healing and bone
formation while improving overall immune function
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