Ch. 13: The Water-Soluble Vitamins

60 mg of tryptophan will produce ___ mg of niacin.

1

Functions of riboflavin include

1. E-yielding metabolism 2. assisting antioxidant rxns

Why are alcoholics more susceptible to Wernicke-Korsakoff syndrome?

1. alcohol increases thiamin excretion in the urine 2. alcoholics consume a diet low in thiamin 3. alcohol decreases thiamin absorption

How are B vitamins present in foods?

1. as vitamins bound to PRO 2. as coenzymes

Why would an average meat-eating person have a low risk for vitamin B12 deficiency?

1. consumption of B12 tends to be 2x the RDA 2. B12 is stored in the liver

Grain products that have been milled are ___ with B vitamins and the mineral iron to lessen the risk of deficiency.

1. enriched 2. fortified

What happens to excess choline in the body?

1. excreted in the urine 2. converted to a related donor of single-C groups

How do we get choline into the body?

1. food intake 2. synthesized by the body

Older adults are at greater risk for pernicious anemia due to

1. lowered production of stomach acid 2. reduced output of intrinsic factor

Taurine functions:

1. photoreceptor activity in the eye 2. platelet aggregation

The coenzyme form of pantothenic acid participates in

1. release of E from CHOs, FATs, and PROs 2. FA synthesis

The functions of vitamin B6 include

1. synthesis of neurotransmitters 2. synthesis of nonessential AAs 3. homocysteine metabolism

A deficiency of riboflavin will appear after ___ of a lack of riboflavin in the diet.

2 months

AI for biotin

30 ug/day for men and women

Enrichment adds ___ back into the food.

4 B vitamins

___ of riboflavin is absorbed via active transport or facilitated diffusion in the small intestine

60 - 65%

B6 plays a major role in

AA metabolism

Do dairy products lower the bioavailability of thiamin?

NO

Does vitamin B6 play a role in the formation of RBC?

NO

Vitamin B6 has NOT been shown in research to help with ___.

PMS

What are functions for all of the water-soluble vitamins?

PRO and AA metabolism E metabolism blood formation and clotting

B12 =

cobalamin

Biotin functions as a ___ for several carboxylase enzymes that add CO2 to various compounds.

coenzyme

Pantothenic acid is part of

coenzyme A

carboxylations =

adding CO2 to compounds

Vitamin C is needed for the production of which protein?

collagen

Coenzymes play an important role in metabolism because they

aid in the function of activating enzymes

Wernicke-Korsakoff syndrome is a thiamin deficiency found in ___.

alcoholics

Which B vitamins participate in E metabolism?

all 8 of them

What is the major fibrous PRO that holds together various structures of the body?

collagen

Vitamin B6 may prevent ___

colon cancer

Neural tube defects that result due to a lack of folate during pregnancy include

anecephaly spina bifida

Vitamin B12 is found naturally in ___ foods only.

animal

Vitamin C may reduce cancer risk due to its ___ properties.

antioxidant

Megadoses of vitamin C

are excreted from the body

Unlike most animals, humans ___ able to synthesize vitamin C.

are not

The RBCs of a folate-deficient person differ from a healthy person by

becoming very large and unable to divide due to the lack of DNA

Rich dietary sources of niacin include

beef fish poultry

A person experiencing weakness, loss of appetite, poor coordination, and edema caused from lack of thiamin is experiencing the deficiency disease known as ___.

beriberi

Raw eggs limit the absorption of

biotin

Which vitamin helps maintain gene stability by binding to the proteins that help DNA fold in the cell nucleus?

biotin

Which enzyme is responsible for the breakdown of biotin?

biotinidase

Signs of scurvy include

bleeding gums slow wound healing

Vitamin B6 ___ be recommended as a treatment for premenstrual syndrome.

cannot

Biotin participates in what type of reaction?

carboxylations

Thiamin is a key component required to release E from the macronutrient

carbs

What transports FAs from the cytosol into the mitochondria?

carnitine

Vitamin-like compounds include

carnitine taurine

Which vitamin deficiency shows no sign of a deficiency disease?

choline

What are good sources of vitamin C?

citrus fruits peppers

Which diets are associated the condition known as pellagra?

corn-based diets

Folate reduces the risk of ___.

developing colon cancer

Pellagra is characterized by

diarrhea dementia dermatitis (and death)

Marginal riboflavin deficiency may occur in people who

do not drink milk

Vitamin C is necessary for the synthesis of ___.

epinephrine thyroxine carnitine

What is true regarding megadoses of vitamin C?

excess vitamin C is excreted from the body

The liver is the main storage site of ___.

fat soluble vitamins

Enriched grain products remain low in

fiber

Enriched grain products remain low in ___.

fiber

What is the most common side effect of a high dose of niacin used to raise levels of HDL-cholesterol?

flushing of the skin

A ___ deficiency leads to megaloblastic anemia.

folate

Folic acid refers to the synthetic form of the B vitamin ___.

folate

Food preparation can destroy 50 - 90% of this B vitamin because it is easily destroyed by heat, oxidation, and ultra violet light.

folate

Name the B vitamin that is required to be added to refined grain products with the aim of preventing neural tube defects.

folate

The coenzymes of which B vitamin are needed for the synthesis and maintenance of new cells?

folate

The water soluble vitamin deficiency that may lead to decreased RBC synthesis and eventually megaloblastic anemia, is due to a lack of the vitamin ___.

folate

Vitamin B12 is required to convert ___ coenzymes to their active forms.

folate

Which B vitamin is key to the formation of the neurotransmitters dopamine and norepinephrine in the brain?

folate

___, a B vitamin, is important in DNA synthesis.

folate

What are some foods that will lower the bioavailability of thiamin?

fresh fish, shellfish coffee, tea blueberries red cabbage, beets, brussel sprouts

The highest folate content may be obtained from eating

fresh fruits and vegetables

Vitamin B6 is responsible for regulation of ___

gene expression

B6 is required for the release of

glucose from glycogen

Food sources high in vitamin C:

green peppers strawberries

High homocysteine levels are a risk factor for

heart attacks AND strokes

B6 converts ___ to the AA ___.

homocysteine cysteine

___ releases riboflavin from its bound forms.

hydrochloric acid

Pantothenic acid is present ___ and supplied by ___.

in all body cells a variety of foods

When either folate or vitamin B12 is lacking, the amount of homocysteine in the body ___.

increases

symptoms of riboflavin deficiency

inflammation of mouth and tongue angular cheillitis dermatitis cracking of tissue around mouth sensitivity to sun confusion

In the US, all bread and cereal products made from milled grains are enriched with which mineral?

iron

Vitamin C enhances the absorption of the mineral ___.

iron

There is no UL set for riboflavin because it

is water soluble and therefore toxic levels cannot be reached

Ariboflavinosis is due to

lack of riboflavin in the diet

Food of animal origin are ___ contributors of choline to the diet.

large

Which foods provide the largest amount of bioavailable folate?

leafy green vegetables legumes liver

Describe a meal rich in thiamin?

lean ham, asparagus, rice, milk

___ thiamin is stored in the body.

little

Side effects of excessive intake of choline include

low BP fishy body odor

How are folate requirements expressed?

mcg as DFE (dietary folate equivalents)

Common food sources for pantothenic acid include

meat mushrooms broccoli milk

main food sources of carnitine

meat and dairy

Food sources of riboflavin include

milk eggs enriched grains

Pantothenic acid storage is

minimal

Where is the main storage site for vitamin B6?

muscle

With dry beriberi, the symptoms are related to the

nervous and muscular systems

Folate is important in the formation of ___.

neurotransmitters

NAD and NADP are coenzyme forms of what B vitamin?

niacin

Pellagra is a _____ deficiency disease.

niacin

Which B vitamin is synthesized from tryptophan?

niacin

Has vitamin C been shown to conclusively prevent heart disease and cancer?

no

Can humans make their own supply of vitamin C? Animals?

no yes

Folate helps to maintain ___.

normal BP

Vitamin B6 helps support ___

normal immune function

Vitamin B6 participates in ___ metabolic reactions.

numerous

Smokers need more vitamin C daily than non-smokers because

of the greater stress placed on the lungs due to the oxidative damage

Pantothenic is derived from the Greek word ___, meaning ___.

pantothen "from every side"

Mushrooms are a good source of which B vitamin?

pantothenic acid

Which water-soluble vitamin is part of coenzyme A, transported bound to RBCs and minimally stored?

pantothenic acid

characteristics of pantothenic acid

part of coenzyme A storage is minimal transported bound to RBCs

The absorption of vitamin B6 is by ___ diffusion.

passive

Thiamin is a coenzyme in the ___ pathway.

pentose phosphate

The risk of riboflavin deficiency increases with long-term use of ___.

phenobarbital

Choline functions as a part of

phospholipids acetylcholine

What term is used to describe when a phosphate group is added to a compound?

phosphorylation

3 food sources rich in thiamin:

pork products legumes sunflower seeds

What are good food sources of vitamin B6?

poultry meat fish

A folate deficiency during pregnancy increases the risk for neural tube defects because folate

promotes the development of the neural tube

In the blood, riboflavin is transported by ___.

protein carriers

Pantothenic acid deficiency is

rare

Ariboflavinosis primarily affects the mouth, skin, and RBCs, causing inflammation of the throat, mouth, and tongue; cracking of the tissue around the mouth, and red, scaly skin is caused by a deficiency of ___.

riboflavin

A deficiency in which vitamins may cause glossitis?

riboflavin niacin vit B6

Long-term use of phenobarbital increases risk of ___

riboflavin deficiency

The deficiency disease for vitamin C is called

scurvy

Where does the absorption of vitamin C occur?

small intestine

Where is thiamin absorbed?

small intestine

Microwaving is similar to ___ in food preparation in terms of retaining the water-soluble vitamins.

steaming

What are the best methods for retaining water-soluble vitamins when preparing food?

stir frying microwaving

Good sources of biotin include

sunflower seeds eggs peanuts liver cauliflower

A riboflavin deficiency usually occurs with a deficiency of several other B vitamins because

these nutrients often occur in the same foods

A deficiency of which vitamin would affect glucose metabolism?

thiamin

Pork, enriched grains, and whole-grain products are excellent sources of ___.

thiamin

There is no UL intake for

thiamin

Wernicke-Korsakoff syndrome is a ___ deficiency.

thiamin

Which vitamin is required for normal functions of the nervous system?

thiamin

What are the B vitamins?

thiamin riboflavin niacin biotin pantothenic acid folate

Choline is absorbed in the small intestine by way of ___ proteins.

transport

T/F: Adults generally get an adequate intake of pantothenic acid.

true

T/F: Generally, almost all niacin that is consumed is absorbed.

true

T/F: Most adults meet the adequate intake for biotin.

true

Where is folate excreted?

urine and feces

What color does riboflavin impart in the urine when consumed in excessive amounts?

yellow

An upper level intake of this B vitamin is set at 100 mg/day, as high intakes can lead to irreversible nerve damage.

B6

What vitamin is used for the synthesis of the neurotransmitters serotonin and dopamine?

B6

Thiamin is a coenzyme required for the metabolism of ___ and ___.

CHOs branched-chain AAs

A high folic acid intake may mask a vitamin ___ deficiency so the FDA limits the amount of this vitamin in nonprescription supplements.

B12

Neurological complications are seen with deficiencies in vitamin ___.

B12

The stomach produces the intrinsic factor that is necessary in order to absorb which vitamin?

B12

Which vitamin deficiency leads to megaloblastic anemia?

B12

Which vitamin has foods of animal origin as its only reliable food source and is the only vitamin that contains a mineral as part of its structure?

B12

Which vitamin is also known as cobalamin?

B12

In what function do all 8 B vitamins participate?

E metabolism

Pantothenic acid is transported bound to

RBCs

Thiamin is transported by

RBCs

The average daily intake for thiamin in men and women is ___ the recommended RDA.

above

The avg daily intake for thiamin in men and women is ___ the recommended RDA.

above

Who is at risk for vitamin B12 deficiency?

vegetarians elderly people w/a malabsorption syndrome

Current research shows that vitamin C has a ___ effect on preventing and treating the common cold.

very modest

Pernicious anemia is related to inadequate ___.

vitamin B12 absorption

Bananas are a rich source of

vitamin B6

Seborrheic dermatitis, microcytic hypochromic anemia, convulsions, depression, and confusion are symptoms of ___ deficiency.

vitamin B6

What vitamin has been used to treat carpal tunnel syndrome and nausea during pregnancy?

vitamin B6

Which B vitamin is important in the synthesis of heme, a nitrogen-containing ring that is inserted into certain PROs to hold iron in place?

vitamin B6

High does of this vitamin slightly increase the risk of kidney stones and iron-absorption disorders.

vitamin C

The category of vitamins that need to be replaced daily are the ___.

water-soluble vitamins

Megadoses of vitamin C ___ be toxic.

will not