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Flashcards in 560C Vit and Min Deck (339)
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151

Which cofactors/vitamins are involved in one of the pathways of homocysteine metabolism?

Betaine
Folic Acid
B12

152

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

Before conception (3 months)

153

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

3. Colorectum

154

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

155

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.

156

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

> 1% of the population has it

157

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

Increased homocycteine concentrations

158

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?

breads
milk products
margarine
fish products
breakfast cereals

Fish products

159

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

Liver and kidney

160

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

Calcium and Phosphorus

161

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

calcium

162

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

163

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


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

164

What are 3 characteristics of rickets?

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

165

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

Osteomalacia

166

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

FALSE

167

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)

168

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.

169

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

circulating 25-OH cholecalciferol

170

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

171

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

carboxylase

172

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

calcium ions

173

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

Warfarin and Coumadin

174

Which TWO proteins depend upon vitamin K for their production?

osteocalcin
matrix Gla protein

175

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

176

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

prevention of calcification

177

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

178

What blood disorders is associated with vitamin K deficiency?

hemorrhagic disease

179

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

FALSE

180

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

plasma phylloquinone