Ch 13 Water soluble vitamins
60 mg of tryptophan will produce ____ mg of niacin.
1 mg
The Upper Level of vitamin B-6 has been set at _____.
100 mg/day
What is the AI for biotin?
30 μg/day.2 This amount is significantly less than the requirements for most of the water-soluble vitamins; remember, 1000 μg equal 1 mg. The diets of adults generally meet the Adequate Intake level. The Daily Value on food and supplement labels is 30 μg. There is no Upper Level for biotin.2
The average daily intake for thiamin in men and women is ______ the recommended RDA.
Above The RDAs for thiamin are 1.2 mg/day for adult men and 1.1 mg/day for women.2 The Daily Value on food and supplement labels is 1.2 mg. In the U.S., for men, the average daily intake for thiamin from food is 1.9 mg/day. For women, it is 1.4 mg/day.9 There appear to be no adverse effects with excess intake of thiamin from food or supplements because it is readily excreted in the urine.
Biotin participates in reactions called carboxylations. Which of the following is the best definition of carboxylations?
Adding carbon dioxide to compounds
What combines with inactive enzymes to form active enzymes able to catalyze specific reactions?
Cofactors
Why would consuming fresh fruits and vegetables contribute more folate?
Folate is destroyed by heat.
The food sources of riboflavin include _____. (Check all that apply.)
Foods rich in riboflavin are liver, mushrooms, spinach and other green leafy vegetables, broccoli, asparagus, milk, and cottage cheese
Which of the following DRIs has not been set for pantothenic acid?
For adults, the Adequate Intake for pantothenic acid is 5 mg/day.2 Adults generally consume the Adequate Intake or more. The Daily Value on food and supplement labels is 5 mg. There is no known toxicity for pantothenic acid, so no Upper Level has been set
Which is true about riboflavin?
In the stomach, hydrochloric acid (HCl) releases riboflavin from its bound forms. About 60 to 65% of the free riboflavin is absorbed, primarily via active transport or facilitated diffusion in the small intestine.15 In the blood, riboflavin is transported by protein carriers. Riboflavin is converted to its coenzyme forms in most tissues, but this occurs mainly in the small intestine, liver, heart, and kidneys.
Select the populations that are at risk of developing a thiamin deficiency.
Individuals who abuse alcohol may experience the thiamin deficiency disorder known as Wernicke-Korsakoff syndrome. Additionally, some individuals—including those with heart failure, gastrointestinal diseases, critical illness, eating disorders, and obesity—are at risk of moderate thiamin deficiency.10,12 The prevalence of thiamin deficiency in older adults is much less common than once thought
Which of the following are good food sources of vitamin B-6?
Meat Poultry Fish
NAD+ and NADP+ are coenzyme forms of which B vitamin?
Niacin
Why are corn-based diets associated with pellagra? (Check all that apply.)
Niacin in corn is unavailable. Corn contains little tryptophan.
Which B-vitamin is used throughout the body in energy metabolism and is part of coenzyme A?
Pantothenic acid
The symptoms of a pantothenic acid deficiency include _____.
Pantothenic acid deficiency is very rare and has been observed only when a deficiency was experimentally induced.2 Its symptoms include headache, fatigue, impaired muscle coordination, burning hands and feet, and GI tract disturbances.
Identify the food sources of thiamin. (Check all that apply.)
Pork sunflower seeds legumes
Which of the following statements are true about pantothenic acid?
Present in all body cells and supplied by a variety of foods Pantothenic is from the Greek word pantothen, meaning "from every side."
What are the 3 different forms of vitamin B-6?
Pyridoxamine Pyridoxal Pyridoxine
Which of the following are considered B-vitamins?
Riboflavin Thiamin Niacin
A deficiency in what can cause glossitis
Riboflavin deficiency, called ariboflavinosis, primarily affects the mouth, skin, and red blood cells. The symptoms include inflammation of the throat, mouth (stomatitis), and tongue (glossitis); cracking of the tissue around the corners of the mouth (angular cheilitis); and moist, red, scaly skin (seborrheic dermatitis) (Fig. 13-8). Poor growth, anemia, fatigue, confusion, and headaches also may occur. Some of the symptoms of ariboflavinosis may result from deficiencies of other B-vitamins because they work in the same metabolic pathways as riboflavin and are often supplied by the same foods.
Which B-vitamin is a component of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)?
Riboflavin is a component of 2 coenzymes that play key roles in energy metabolism: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).16 These coenzymes, also referred to as flavins, have oxidation and reduction functions. (See Section 9.1 in Chapter 9.) FAD is the oxidized form of the coenzyme. When it is reduced (gains 2 hydrogens, equivalent to 2 hydrogen ions and 2 electrons), it is known as FADH2.
Which of the following are characteristics of pantothenic acid?
Storage is minimal Transported bound to red blood cells Part of coenzyme A
Thiamin is a key component required to metabolize the macronutrient ______.
The coenzyme thiamin pyrophosphate (TPP) is required for the metabolism of carbohydrates and branched-chain amino acids.8 TPP is necessary for 2 different types of reactions. First, it works with specific enzymes to remove carbon dioxide (known as decarboxylation) from certain compounds. The conversion of pyruvate to acetyl-CoA, a critical reaction in the aerobic respiration of glucose, is an example of the decarboxylation action of TPP.
Which is true about the Upper Level for thiamin?
There is no Upper Level established for this nutrient.
Which is true about the transport and storage of thiamin?
Thiamin is readily absorbed in the small intestine by a sodium-dependent active absorption process. It is transported mainly by red blood cells in its coenzyme form (thiamin pyrophosphate). Little thiamin is stored; only a small reserve (25-30 mg) is found in the muscles, brain, liver, and kidneys.
What vitamin is needed by nearly all amino acids for metabolism?
Vitamin B-6
Glossitis results in _____.
a painful, inflamed tongue
Dietary folate equivalents (DFE) reflect the differences in the ______ of food folate and synthetic folic acid.
absorption
Coenzyme A, the coenzyme form of pantothenic acid, is essential for the formation of ______.
acetyl-CoA
Coenzymes play an important role in metabolism because they _____.
aid in the function of activating enzymes
Generally, _______ niacin that is consumed is absorbed.
almost all
Adults generally get _______ intake of pantothenic acid to sustain health.
an adequate
In infants with a deficiency of ____, symptoms include skin rash, hair loss, convulsions, and impaired growth.
biotin
This vitamin's discovery was linked to "egg-white injury."
biotin
Which vitamin helps maintain gene stability by binding to the proteins that help DNA fold in the cell nucleus?
biotin
Biotin functions as a(n) ______ for several carboxylase enzymes that add carbon dioxide to various compounds.
coenzyme
Niacin serves as a ______ in energy metabolism.
coenzyme
The microcytic hypochromic anemia associated with a vitamin B-6 deficiency arises due to ______.
decreased hemoglobin synthesis
There _____ appear to be adverse effects from consuming large amounts of riboflavin.
does not
Functions of riboflavin include ______.
energy-yielding metabolism assisting antioxidant reactions
Grain products that have been milled are ______ with B-vitamins and the mineral iron to lessen the risk of deficiency.
enriched
What happens to excess niacin?
excreted in urine
The coenzyme form of pantothenic acid participates in _______.
fatty acid synthesis the breakdown of carbohydrates, protein, alcohol, and fats
Enriched grain products remain low in ______.
fiber
Biotin is found in food as _____.
free biotin biocytin
There is no UL set for riboflavin because it _____.
has limited absorption and rapid excretion, with no known adverse effects from consuming large quantities
Water-soluble vitamins ______.
help maintain body tissues are needed for the growth of body tissues are needed for the normal function of body tissues
The prevalence of thiamin deficiency in older adults is ____.
less common than thought
Most adults ______ the adequate intake level for biotin.
meet
Common food sources for pantothenic acid include _____.
milk meat peanuts beans
Where is the main storage site for vitamin B-6?
muscle
Biotin functions as a(n) ______ for several carboxylase enzymes that add carbon dioxide to various compounds.
nerve damage
Which B-vitamin is synthesized from tryptophan?
niacin
Which B-vitamin, in high doses, was historically prescribed by physicians to increase HDL-cholesterol and lower triglyceride levels?
niacin
To account for preformed niacin in foods and niacin synthesized from tryptophan, niacin is expressed as ____.
niacin equivalents
The function of PLP, the coenzyme form of vitamin B-6, pertains mainly to enzymatic reactions involving ______.
nitrogen-containing compounds
Currently, niacin-containing medications are _____ recommended for most individuals with cardiovascular disease.
no longer
Which B-vitamin is found in a wide variety of foods?
pantothenic acid
Corn-based diets are associated with which condition?
pellagra
Milk is an excellent source of ____.
riboflavin
Water-soluble vitamins are essential organic substances needed in _____ amounts.
small
The pantothenic acid portion of coenzyme A is released during digestion in the ____.
small intestine
Where does the breakdown of biotin occur?
small intestine
Where is thiamin absorbed?
small intestine
Riboflavin's conversion to its coenzyme form occurs mainly in the _____.
small intestine, also heart and liver
Pork products are excellent sources of _____.
thiamin
The B vitamin required as a coenzyme to metabolize carbohydrates and some amino acids is _____.
thiamin
Vitamin B-6 has a long history as a treatment for _____.
treatment for carpal tunnel syndrome, premenstrual syndrome (PMS), and nausea during pregnancy.
Which was the second vitamin to be discovered?
vitamin B
Since a high folic acid intake may mask a ______ deficiency, the FDA limits the amount of folic acid in nonprescription supplements.
vitamin B-12
Which vitamin is also known as cobalamin?
vitamin B-12
Good food sources of biotin include ____.
whole grains, mushrooms, egg yolks, nuts, and legumes
