Name 3 active forms of Vitamin A and describe functions of each.
Retinol: Form of vitamin A you get from the diet, supports reproduction (menstrual cycle and sperm development), major transport and storage
form of the vitamin.
Retinal: Active in vision, intermediate in the conversion of retinol to retinoic acid.
Retinoic Acid: Acts like a hormone, regulates cell differentiation, growth (bone elongation), immunity and embryonic development, normal development of
epithelial linings, cell development (differentiation).
What are carotenoids?
Pigments commonly found in plants and animals, some of which have vitamin A activity; the carotenoid with the greatest vitamin A activity is beta-carotene.
What types of cells are affected by vitamin A deficiency?
proteins and epithelial cells.
Describe the drug Accutane. Why do doctors require female patients to use birth control while taking Accutane?
Accutane is made from retionoic acid; it’s effective against deep lesions of cystic acne.
Itis highly toxic, especially during growth, and has caused birth defects in infants when women have taken it during their pregnancies; that’s why doctors recommend women to use two effective forms of contraception at least once a month after discontinuing its use.
Describe the various roles of vitamin D in the body.
Increase/maintain the absorption of calcium
Regulation of phosphorus
Prevents cancer tumor growth
Muscles-Stronger muscles with increased vitamin D
Lower blood pressure
When calcium is adequate in the diet, on which target tissue does active vitamin D act primarily?
What percent of dietary calcium is absorbed when normal amounts of vitamin D are present in the body?
Under what conditions are longer sun exposures needed for production of vitamin D?
Elderly - Can only make ¼ vitamin D compared to when they were younger.
Latitude - No sun exposure in the north.
Sunscreen - Anything over 8 SPF will decrease vitamin D synthesis.
Describe the function of vitamin E in the body.
Stabilize cell membranes
Regulate oxidation reactions
Protect polyunsaturated fatty acids and vitamin A
What are free radicals and how are they formed? What parts / molecules of the cells are vulnerable to damage from free radicals?
Free radicals: Uncharged molcules (typically highly reactive and short lived), having an unpaired valence electron.Phospholipids of the bilayer membrane are damaged by free radicals.
Vitamin E is an antioxidant that neutralizes free radicals and prevents the oxidation of polyunsaturated fatty acids and protects other lipids and related compounds.
What form of vitamin E is most biologically active in the body?
Which form of vitamin E in supplements is better utilized in the body, natural or synthetic? What is the isomeric form of natural and synthetic alpha tocopherol in supplements?
Natural form (D) of vitamin E is better utilized than synthetic (DL).
What drug is enhanced by high intakes of vitamin E. What effect does this have in the body?
Extremely high doses of vitamin E may interfere with the blood-clotting action of Vitamin K and enhance the effects of drugs used that oppose blood-clotting called anti-coagulants, causing hemorrhage/increase
What are the primary functions of vitamin K in the body?
Synthesis of blood-clotting proteins and bone proteins; bone mineralization
What is osteocalcin and what is its function in bone? How does vitamin K affect osteocalcin?
Osteocalcin is a protein found in the bone that is secreted solely by osteoblasts and was thought to play a role in the body’s metabolic regulation and is
Implicated in bone mineralization and calcium ion homeostasis.Vitamin K and osteocalcin are instrumental to make bones harder.
What are the major foods and non-food sources of vitamin K?
Food: Liver, leafy green vegetables, cabbage-type vegetables, milk, eggs
Non-food: Bacterial synthesis in the digestive tract (makes 50% of your needs).
Is vitamin K deficiency common or rare? Under what conditions can vitamin K deficiency occur? What are the symptoms of vitamin K deficiency?
Vitamin K deficiency is rare.
Secondary deficiency may occur in two circumstances:
Whenever fat absorption falters, as occurs when bile production fails, vitamin K absorption diminishes.
Some drugs disrupt vitamin K synthesis and action in the body - antibiotics kill the vitamin K-producing bacteria in the intestine and anti-coagulant drugs interfere with vitamin K metabolism and activity.
Symptoms of vitamin K deficiency: Hemorrhaging.
Why do infants receive a dose of vitamin K at birth?
Infants are born with a sterile intestinal tract, and vitamin K-producing bacteria take weeks to establish themselves; and plasma prothrombin is
low (this reduces the likelihood of fatal blood-clotting during the stress of birth).
Vitamin K is not transferred from the mother to the child.Infants are susceptible to hemorrhaging.
What effect does high levels of vitamin K have on anticoagulant drugs?
High doses of vitamin K can reduce the effectiveness of anticoagulant drugs used to prevent blood clotting. Increasing vitamin K will increase blood clotting.