Flashcards in Section E Deck (41):
What is a vitamin?
A substance essential for the maintenance of normal metabolic function, but is not made in the body and therefore must be provided from an outside source
Which vitamin deficiency causes scurvy?
Which vitamin deficiency causes rickets?
Which vitamin deficiency causes polyneuritis?
What is another name for vitamin B1?
Which vitamin deficiency causes pernicious anemia?
Which vitamin deficiency causes pellagra?
What is another name for vitamin B3?
Water soluble vitamins?
Vitamin C and 11 vitamin Bs
Fat soluble vitamins?
Vitamins A, D, E and K
Dietary recommended intakes
Estimated average requirement. The value is determined to meet the requirements for 50% of the people in any one category based on age, gender and ethnicity
Recommended daily allowance. Daily intake sufficient to meet the needs of 97% to 98% of healthy people in a group.
Adequate intake. Recommended daily intake based on observed or scientific data for specific groups of individuals.
Upper limit. The highest recommended daily intake that is not likely to pose an adverse health risk to all individuals.
What are the two approaches to vitamin therapy?
Nutritional approach or megavitamin approach
What are illnesses that may require vitamins as a dietary supplement?
Hyperthyroidism, fever, tissue wasting (among others)
Which water soluble vitamin may cause toxic effects? What are they?
Vitamin B6 may cause nerve injury
What is another name for vitamin B6?
What is the RDA for vitamin A in healthy individuals? Smokers?
Healthy = 60 mg; smokers = 100 mg
Which tissues require vitamin C for their formation?
Collagen and intercellular ground substance
Why would vitamin C deficiency cause bleeding?
Disrupts collagen and intercellular ground substance, which are required to hold cells together; affects blood vessel framework
How did Jacques Cartier cure scurvy?
Spruce leaf extract
Administered vitamin C in excess of RDA; found common cold was not prevented or shortened (number of days missed from work reduced)
What are the risks of vitamin C megadosage?
Diarrhea, kidney stones (from excretion of oxalate), rebound scurvy (due to high metabolism of vitamin C)
How many members of the vitamin B family are there?
What sources are the vitamin Bs isolated from?
Liver and yeast
Why should women of child-bearing age take folate?
Decreases the incidence of neural tube defects (such as spina bifida) in their offspring
What are benefits of vitamin B6?
Decreased serum concentrations of homocysteine and a lower risk of heart disease
Which vitamin B do 10-30% of americans over the age of 60 have difficulty absorbing?
Describe the RDA for vitamin A.
RDA = 1000 ug = 1000 retinol equivalents (1 retinol equivalent = 1 ug retinol = 6 ug beta-carotene)
What are the effects of vitamin A deficiency?
Growth and development retarded, night blindness/dry eye surface, changes bronchiolar cells/ increases change of respiratory infection, causes dry/thick/horny skin
What are the effects of excessive vitamin A intake?
dry itchy skin, vomiting, headache, feeling of pressure in the head and an enlarged liver and spleen
What are therapeutic uses for vitamin A?
Treatment of deficiency, periods of increased need (pregnancy, lactation, infancy), acne and skin diseases
What are sources of vitamin D?
Dietary (meat and fish) or by the action of sunlight on provitamin D (present in the skin)
Describe the conversion pathway of vitamin D.
Provitamin D (skin) -> Vitamin D (food) -> (liver) -> 25- Hydroxyvitamin D -> (kidneys) -> 1,25-Dihydroxyvitamin D (active form)
What are the actions of vitamin D?
Increases the absorption of calcium and phosphate from the intestine, regulation of blood calcium level, removal of calcium from older bone
Results of vitamin D deficiency?
Decreased calcium and phosphate absorption from intestine, decreased blood calcium level, calcium removed from bone (bowleggedness)
What is the RDA of vitamin D?
400 I.U; women over 55 = 1000 IU (+ 1500mg elemental Ca); men over 55 = 1200 mg elemental Ca; women = 1000 IU (to prevent breast cancer)
What is the RDA for vitamin E?