Ch. 10 Water-Soluble Vitamins Flashcards
Thiamin (B1)
Fxn: coenzyme
Deficiency: Beriberi
- ->S and S: loss of appetite, muscular weakness, severe nervous disorders, general weakness, edema and wasting
- ->at risk: alcoholics
- ->why: malnourishment, decrease in hepatic storage, ethanol inhibits absorption
Toxicity: unlikely
Food Sources: pork, fortified or enriched grain products, whole grains
*destroyed by prolonged cooking, extremely sensitive to heat
Riboflavin (B2)
Fxn: coenzyme
-associated w/transport of electrons to electron transport chain/ATP production
Deficiency: not common
–S and S: digestive disturbances, general weakness, eye abnormalities
Toxicity: unlikely
Food Sources: milk, milk products, whole grain, fortified or enriched grain products
*destroyed by UV light and irradiation, not destroyed by cooking (stable to temp changes)
Niacin (B3)
Fxn: coenzyme
Deficiency: Pellagra (4Ds=diarrhea, dermatitis, dementia, death)
Toxicity: niacin flush (red, tingly, itchy skin)
Food Sources: protein foods (including nuts), whole grain, fortified and enriched grain products
Additional: body can make from AA tryptophan
–>treatment of hypercholesterolemia
Biotin (B7)
aka vitamin H
Fxn:
- coenzyme
- metabolism of CHO and FAT
- assist the addition of CO2 to other compounds (TCA cycle)
- helps break down certain AA
Deficiency: rare
Toxicity: rare
- ->scaly inflamed skin, tongue, and lip changes
- ->poor appetite and nausea
- ->anemia
- ->muscle pain and weakness
Food Sources: widespread, uncooked eggs
Pantothenic Acid (B5)
Fxn:
- coenzyme
- essential for metabolism of CHO, FAT, and PRO (energy production)
Deficiency: rare
Toxicity: rare
Food Sources: widespread, chicken, beef, potatoes, tomatoes
Pyridoxine (B6)
Fxn:
- coenzyme
- activate enzymes needed for metabolism of CHO, PRO, and FAT
- synthesize nonessential AA via transmission
- synthesize neurotransmitters (primarily serotonin)
- synthesize hemoglobin and WBC
Deficiency: ETOH contributes to destruction and loss from body
–>depression, vomiting, skin disorders, nerve irritation, impaired immune system
Toxicity: Yes. Nerve damage - basal ganglia
Food Sources: meats, legumes, non-citrus fruits
Folate (B9)
aka Folacin or Folic Acid
*stored in liver
Fxn:
- coenzyme (convert vitamin B12 to its coenzyme form)
- synthesize DNA
- synthesize RBC
Recommendations:
- -adults: 400 micrograms/day
- -Pregnant women: 600 micrograms/day
- -Planning to conceive: 400 micrograms/day
Deficiency: neural tube defects
–> spina bifida and anencephaly; macrocytic anemia (megaloblastic anemia), alcoholism
Toxicity: yes; masks vitamin B12 deficiency
Food Sources: fortified grains, green leafy vegetables, legumes, seeds, liver
Cobalamin (B12)
Fxn: coenzyme
Deficiency:
- -Pernicious anemia
- -Achlorhydria occurs especially in elderly individuals
- -Atrophic gastritis
- ->At Risk for Deficiency: Vegans
Toxicity: rare
Food Sources: animal products (meat, cheese, eggs…)
Vitamin C (ascorbic acid)
Fxn:
- reducing agent (antioxidant)
- enhances iron absorption
- synthesis of collagen
- immune functions (may reduce duration of symptoms by a day or so; does NOT prevent colds)
- wound healing
Recommendations:
- -Men: 90 mg/day
- -Women: 75 mg/day
- -Smokers: add +35 mg/day
Deficiency: Scurvy
–>bleeding gums, poor wound healing
Toxicity: yes (TUL=2000mg/day)
–>Hemochromatosis (increase in iron absorption, oxalate kidney stones, erodes tooth enamel)
Food Sources: citrus fruits, cabbage type vegetables, dark green vegetables
Discuss the importance of folate in the development of neural tube defects. How does a woman meet her folate requirement?
Folate helps in neurotransmitter formation.
Spina bifida is spinal malformation, paralysis; occurs before pregnancy is detected
Anencephaly: no brain cortex (incompatible with life), stillborn or die within hours.
Folate drastically decreases the risks of the baby having these defects.
The woman, if planning to conceive, should be taking 400 micrograms/day. If the woman is pregnant, she needs to be consuming 600 micrograms/day.
*Note: Spina bifida and Anencephaly occur before pregnancy is detected. Taking more folate after discovering pregnancy won’t prevent neural tube defects because they’ve already formed. It’s still important to take folate during pregnancy though! Helps baby develop.
Understand folic acid fortification. Why was this established?
Government requires folic acid fortification of enriched breads and flours. May prevent 50% of neural tube defects.
Established because so many babies were being born with neural tube defects.
Define atrophic gastritis.
Chronic inflammation of the stomach accompanied by a diminished size and functioning of the mucous membrane and glands. This condition is also characterized by inadequate HCl and Intrinsic Factor (IF)—two substances needed for vitamin B12 absorption
Vitamin B12 deficiency
Define pernicious anemia
A blood disorder that reflects a vitamin B12 deficiency caused by lack of intrinsic factor and characterized by abnormally large and immature red blood cells
Causes: physiological, surgical
S and S: nerve degeneration, weakness, tingling/numbness in extremities (paresthesia), paralysis and death, looks like folate deficiency
Explain how one with atrophic gastritis can develop poor vitamin B12 status
Atrophic gastritis is a condition that damages the cells of the stomach. Without healthy stomach cells, production of HCl and IF diminishes. Even with adequate intake from foods, vitamin B12 status suffers.
Explain causes for pernicious anemia. What are the S/S?
The vitamin B12 deficiency caused by atrophic gastritis and a lack of IF is known as pernicious anemia.
Sometimes a lack of IF is caused by genetic defects. In such cases, or when the stomach had been injured and cannot produce enough of the IF, vitamin B12 must be given by injection to bypass the need for intestinal absorption. Can also be delivered via nasal spray.
S/S: • Nerve degeneration, weakness • Tingling/numbness in extremities (parasthesia) • In severe cases, paralysis/death • Looks like folate deficiency
