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Flashcards in 560C Vit and Min Deck (339)
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Which cofactors/vitamins are involved in one of the pathways of homocysteine metabolism?

Folic Acid


Prevention of birth defects with folic acid is best accomplished by starting supplementation when?

Before conception (3 months)


Prevention of cancer with optimal folate nutrition appears most promising for cancer in which tissue?

3. Colorectum


Which one of the following groups does NOT have a higher risk B12 deficiency?

1. People regularly exposed to nitrous oxide gas
2. People using gastric acid-reducing drugs long-term
3. People with gallbladder disease
4. People with atrophic gastritis
5. People over 50 years of age
6. People with impaired pancreatic exocrine function

3. People with gallbladder disease


Which of the following is FALSE?

1. Fortification of food with folic acid is mandated by law, but not fortification of B6 or B12.
2. Pellagra symptoms may appear during B6 deficiency, because this vitamin is required in the process of obtaining niacin from tryptophan.
3. The Tolerable Upper Intake level for folic acid is based on evidence of increased cancer risk.
4. Low-dose oral contraceptives currently in use are as likely to interfere with folic acid nutrition were older, high-dose oral contraceptives.

4. Low-dose oral contraceptives currently in use are as likely to interfere with folic acid nutrition were older, high-dose oral contraceptives.


What is the criteria for a genetic difference to be called a polymorphism?

> 1% of the population has it


A genetic polymorphism that decreases the activity of N5,N10 methylene tetrahydrofolate reductase has been identified. This would cause _____.

Increased homocycteine concentrations


All except one of the following foods may be high in vitamin D because they are often fortified? Which one is least likely to be fortified?

milk products
fish products
breakfast cereals

Fish products


Which two organs are essential for the normal hydroxylations that convert cholecalciferol into systemically-active vitamin D hormone?

Liver and kidney


The primary function of vitamin D is to regulate absorption and metabolism of which 2 minerals?

Calcium and Phosphorus


Place the phrases below in order to explain the response of the body to a decline in serum ____ levels.

1. Increased release of PTH
4. Increased synthesis of 1,25-(OH)2 D3
3. Increased synthesis of calbindin
6. Increased calcium absorption



What are 3 functions of calcitriol in the intestine?

1. synthesis of calbindin
2. modulation of gene expression
4. induction of changes in brush border composition


What are 3 risk factors is associated with a vitamin D deficiency?

1. Aging
2. Crohn's disease
3. Kidney disorders


What are 3 characteristics of rickets?

1. Curved spine
2. Bowed legs
4. Thoracic deformities


What disorder is associated with insufficient serum calcium and phosphorus, and leads to defective bone mineralization with preservation of bone matrix?



T/F: Overexposure to ultraviolet radiation can result in excessive production of vitamin D in the body.



Dosages in excess of 10,000 IU/day of vitamin D for several months can result in which TWO events?

1. hypercalcemia
2. nephrolithiasis (The process of forming a kidney stone)


Choose the TWO answers that represent the values set by the 2010 RDA (not the 1997 DRI for Adequate Intake) for vitamin D.

1. 20 mcg for adults over 70
2. 15 mcg for all adults over 70
3. 15 mcg for adults under age 71 and children over age 1
4. 5 mcg for adults under age 51
5. 10 mcg for adults between 51 and 70

1. 20 mcg for adults over 70
3. 15 mcg for adults under 70 and children over age 1

1 IU is the biological equivalent of 0.025mcg cholecalciferol or ergocalciferol.


In assessing the vitamin D status of an individual, which measure would you use?

circulating 25-OH cholecalciferol


Regarding vitamin K sources, which of the following is NOT true?

1. Menaquinones are synthesized by intestinal bacteria
2. Dietary vitamin K is primarily menaquinones
3. Menaquinones are found in animal foods
4. Menadione is not found in nature
5. Phylloquinone is found in plant foods

2. Dietary vitamin K is primarily menaquinones


For what type of enzyme does vitamin K act as a cofactor?



Vitamin-K dependent modification of proteins such as the clotting factors affects the binding of which mineral ion by those proteins?

calcium ions


Which TWO names refer to anticoagulants that antagonize vitamin K action?

Warfarin and Coumadin


Which TWO proteins depend upon vitamin K for their production?

matrix Gla protein


Compared to the Adequate Intake (AI) set for vitamin K, how much dietary vitamin K intake was associated with reduced hip fracture in the Framingham Heart Study?

About twice the AI for adult males


What role is vitamin K most likely to play in the health of soft tissue structures?

prevention of calcification


Name four groups associated with an increased risk for a vitamin K deficiency?

1. fat malabsorption disorders
2. chronic antibiotic treatment
4. newborn infants
5. liver damage or disease


What blood disorders is associated with vitamin K deficiency?

hemorrhagic disease


T/F: None of the forms of vitamin K have toxic potential.



Which one of the following methods for determining vitamin K status is most likely to reflect recent intake rather than tissue status?

plasma phylloquinone