Water Soluble Vitamins Study Guide | Nutrition Exam 2

T/F: Vitamin C is essential for all mammals

FALSE

-- NO; only essential for HUMANS, primates, fruit bats, guinea pigs, and few birds

(nonessential for most animals/plants since made from glucose & galactose)

What is the oxidized and reduced forms of Vitamin C?

Reduced = Ascorbic Acid

Oxidized = Dehydroascorbic acid

What can Vitamin C donate? How many?

2 Hydrogens

What are the 4 general functions of Vitamin C?

1) Coenzyme

2) Antioxidant

3) Pro-oxidant

4) Other

Vitamin C is a coenzyme for connective tissue, allowing what two things to occur?

1) Collagen synthesis

2) Hydroxylation of proline & lysine

What is required for the hydroxylation of proline and lysine, in addition to Vitamin C?

Iron

Vitamin C as a coenzyme, in addition to connective tissue involvement, is needed for what 5 things?

1) Metabolically active tissue

2) Conversion of DA or NE

3) Synthesis of carnitine & bile

4) Metabolism of folate & tryptophan

5) Absorption of nonheme iron

Nearly all reactions used to maintain either _____ or _______ in a reduced state in order for the enzyme to work?

Iron or Copper

As an antioxidant, Vitamin C will donate ____ or _____ to reduce free radicals in cell and also is used to regenerate _________.

H or electrons

Regenerate Vitamin E

As a Pro-oxidant, Vitamin C will reduce what two ions, since metals generate reactive oxygen species & free radicals?

Cupric ions to cuprous

Ferric ions to Ferrous

Why does Vitamin C Deficiency cause scurvy?

The body cannot synthesize sufficient collagen for proper wound healing

vitamin C is required by prolyl hydroxylase

May find w/ poor diet, alcoholism, or drug habits

Who has the highest Vitamin C requirement? What are the numbers for men, women, and smokers?

Men = 90 mg (highest)

Women = 75 mg

Smokers = 35 mg

What are the sources of Vitamin C? (4)

1) Bell peppers

2) Citrus fruits & fruit juices

3) Broccoli

4) Dark green leafy veggies

NOTE: Plants!

What are the signs/symptoms for a Vitamin C deficiency? (7)

1) Easy bruising

2) Pinpoint hemorrhages

3) Bone fracture

4) Poor wound healing

5) Bleeding Gums

6) Tooth loss

7) Corkscrew hair

What are the 4 H's of Scurvy?

1) Hemorrhagic signs (poor wound healing)

2) Hyperkeratosis of hair follicles

3) Hypochondriasis (psychological manifestations)

4) Hematologic (impaired collagen synthesis & decreased iron absorption)

What causes Vitamin C to be unstable? (3)

Oxygen

Heat

Basic pH (ex: baking soda)

T/F: Fresh veggies contain more Vitamin C than frozen

FALSE

Frozen contains more Vit C than fresh

Since Vitamin C is easily extracted in water, prepared (cooked) veggies that have been refrigerated for 24 hours has lost about ___% of its Vitamin C?

50%

Is there Vitamin C toxicity? If so, what does it cause?

YES

-- causes diarrhea

Unabsorbed Vit C may cause osmotic diarrhea from LI fermentation

What two types of patient conditions should be cautioned against taking Vitamin C supplementation?

1) Kidney disease (increase risk of kidney stones since increases abs of oxalate)

2) Impaired Iron Metabolism: Iron toxicity (Hemochromatosis, Thalassemia, Sideroblastic anemia; helps w/ nonheme absorption)

What is the acronym for remembering the B vitamins? What are each of the B vitamins?

TRN Past Palmer on Brady For Coffee

T = Thiamin (B1)

R = Riboflavin (B2)

N = Niacin (B3)

P = Pantothenic acid (B5)

P = Pyridoxal Phosphate (B6)

B = Biotin (B7)

F = Folate (B9)

C = Cobalamin (B12)

What is the other name for B1?

Thiamin

What structure is found in Thiamin (B1)?

Thiazole ring

What are the functions for each form of thiamin (TPP/TDP & TTP)?

TPP/TDP = Coenzyme

TTP = Nonenzymatic; Nervous system involvement

What are the three forms of thiamin? Which two are the MC (80%)?

TPP, TDP = 80%

TTP = Other

In what two processes does Thiamin (TPP/TDP) act as a coenzyme?

1) Energy production in pyruvate to acetyl CoA (dehydrogenase)

2) NADPH and pentose synthesis (transketolase)

For the nonenzymatic, nervous system function of Thiamin (TTP), it regulates what two ion in nerve conduction? What ion does it donate for synaptic proteins?

Regulates Na channels & Cl- transport in nerve conduction

P donor for synaptic proteins

What are the 5 sources of Thiamin (B1)?

1) Yeast

2) Meat (pork)

3) Whole grains

4) Enriched grains

5) Legumes

NOTE: think grains/bean and then pork (meat)

What are anti-thamin factors? (4)

1) Lost in water

2) Destroyed by heat and basic pH

3) Thiaminases (raw fish/shellfish)

4) Destroyed by phenolic acids in coffee, tea, blueberries, black currants, Brussel sprouts, red cabbage)

NOTE: exacerbated in presence of Ca or Mg

What are the 3 main targets of a thiamin deficiency?

1) Peripheral nerves (numbing and paralysis)

2) Heart (edema and fatigue)

3) Brain (decreased alertness)

What is chronic thiamin deficiency called?

Beriberi

What type of chronic thiamin deficiency is low thiamin + high carb intake, with muscle weakness, extremity wasting, peripheral neuropathy, bilateral tender calf muscles, symmetrical foot drop?

Dry beriberi

What type of chronic thiamin deficiency, with enlarged heart, rapid heartbeat, peripheral edema, and high blood pressure?

Wet beriberi

What type of chronic thiamin deficiency is a chronic infant deficiency, breastfed by mothers with poor thiamin intake, anorexia, nausea, vomiting, and lactic acidosis?

Acute beriberi

What is chronic thiamin deficiency in alcoholics, where there is decreased thiamin intake and absorption, increased thiamin utilization, with symptoms such as psychosis, delirium, ataxia of gait and stance, anorexia, vomiting, and enlarged heart?

Wernicke-Korsakoff syndrome

What is the MC nutritional deficiency in alcoholics?

Thiamin

What is the other name for B2?

Riboflavin

What populations is at risk for thiamin deficiency? (5)

1) Alcoholic

2) Older adults (decreased absorption)

3) HIV/AIDS (metabolic changes)

4) Diabetes (over-excreting thiamin)

5) Gastric bypass patients (decreased intake)

What are the coenzyme forms of Riboflavin (B2)?

FAD & FMN

What are the 3 functions of Riboflavin (B2)?

1) Redox rxn

2) ETC, coenzymes for dehydrogenases, 1st step in B-ox and Krebs

3) Synthesis of nucleic acids, niacin, folate, and B6

Which steps in B-oxidation uses riboflavin?

Steps 1 & 3 (OHOT)

What are 6 dietary sources of riboflavin (B2)?

1) Cow's milk

2) Enriched grains

3) Almonds

4) Soybeans

5) Eggs

6) Meats

Animal products & nuts/beans/grains

What is Riboflavin deficiency called?

Ariboflavinosis

What is the other name for B3?

Niacin

What are symptoms of Ariboflavinosis? What are the KEY symptoms?

Early signs = photophobia, burning and itching of eyes, soreness of mouth, anemia, cataracts, peripheral neuropathy, seborrheic dermatitis, corneal vascularization

-- Cheilosis (all around dryness)

-- Angular stomatitis (cracking at corners of mouth)

-- Glossitis & MAGENTA TONGUE

What are the 2 forms of Niacin (B3)?

NAD & NADPH

What is the main function for Niacin (B3)?

Coenzyme for dehydrogenases (H acceptors/donors in redox rxns)

What is NADH used for w/ Niacin (B3)? (4)

1) Glycolysis

2) Krebs cycle

3) B-oxidation

4) Ethanol metabolism

What is NADPH used for w/ Niacin (B3)? (3)

1) FA synthesis

2) cholesterol synthesis

3) folate synthesis

What enzymes use B1, B2, & B3? (Thiamin, Riboflavin, Niacin)

Dehydrogenases

Which step in B-oxidation uses niacin?

Oxidation II (from OHOT)

NOTE: oxidation I uses FADH2!!!

What is Niacin (B3) made from?

Tryptophan

What are the coenzymes needed to make Niacin (B3) from tryptophan? (4)

1) NADPH

2) Riboflavin (B2)

3) Vit B6

4) ATP

What is the cofactor needed to make Niacin (B3) from tryptophan?

Iron

What are the 8 dietary sources of Niacin (B3)? What is the one other additional source of Niacin?

1) Enriched cereals

2) Chicken

3) Fish

4) Pork

5) Beef

6) Peanuts

7) Yeast

8) Coffee

Some nicotinic acid produced by GUT microbiome

NOTE: MEAT; grains/nuts

What is Vitamin B3 (Niacin) Deficiency called?

Pellagra

What are the 4 D's of Pellagra?

1) Dermatitis (sunburn on face/neck/extremity)

2) Dementia (headache, memory loss, confusion, disorientation)

3) Diarrhea (digestive abnormalities from diarrhea or vomiting can cause inflammation of mucus membranes of the mouth and GI tract)

4) Death

Diets high in what foods are more likely to cause pellagra (Vitamin B3; Niacin deficiency)?

3 M's (Southern US where corn is staple)

1) Meat (pork back fat)

2) Meal (cornmeal)

3) Molasses

What deficiency is often found with pellagra (which is a niacin deficiency)?

Tryptophan deficiency

What is the other name for B5?

Pantothenic Acid

Can there be niacin toxicity? If so, what does it cause?

YES

1) Vasodilation

2) Heartburn

3) Liver Damage

4) Gout

5) Impaired blood glucose

What is are the functions of Pantothenic acid (B5)? (2)

1) Part of CoA & ACP

2) Coenzyme (CoA)

What step is Pantothenic acid (B5) used in?

Pyruvate --> Acetyl-CoA transition step

Enzyme: CoA!!!

NOTE: requires NAD--> NADH + H+; release CO2

When Pantothenic acid (B5) is used as a Coenzyme w/ CoA, what is it involved in the metabolism of? (3) What does it help synthesize? (6)

Metabolism: Carbs, lipids, proteins

Synthesis:

1) FA

2) Cholesterol

3) Phospholipids

4) NT

5) Sphingolipids (nerves)

6) Heme

What 3 vitamins are involved in the Pyruvate --> Acetyl-CoA transition step?

B1, B3, B5

What are 9 dietary sources of Pantothenic acid (B5)? What is one additional source of Pantothenic acid (B5)?

1) Meat

2) Poultry

3) Egg yolk

4) Legumes

5) Whole grains

6) Potatoes

7) Broccoli

8) Mushrooms

9) Avocado

-- Some produced by GUT microbiome

Is there Pantothenic acid (B5) toxicity? If so what does it cause?

NO

(no toxicity/TUL reported)

T/F: Pantothenic acid (B5) is destroyed in its sources with cooking & freezing

TRUE

What is Pantothenic acid (B5) Deficiency called?

Burning Foot Syndrome

What are 6 symptoms of Burning Foot Syndrome (Pantothenic Acid Deficiency)?

1) Numb toes

2) Burning of hands/feet (nerve inflammation)

3) Depression

4) Fatigue

5) Insomnia

6) Weakness