Chapter 8: Vitamins

Question 1

define: vitamins

Answer 1

Vitamins are organic micronutrients that facilitate body processes

Question 2

What is the main function of vitamins?

Answer 2

Vitamins can function as coenzymes

Question 3

Fill in the blank: all vitamins must be converted first before it can be a coenzyme except ________

Answer 3

Vitamin C

Question 4

Compare water soluble vitamins to fat soluble vitamins in terms of

• transport
• storage
• consumption frequency
• toxicity

Answer 4

water soluble vitamins

• transport: none needed
• storage: not stored; free in aqueous compartments; excreted in urine
• consumption frequency: required more frequently from diet (everyday)
• toxicity: excreted by kidney; less likely to be toxic (possible from too much supplements)

fat soluble vitamins

• transport: lipoprotein transporter required
• storage: stored in adipose tissue
• consumption frequency: required less frequently from the diet (every few days)
• toxicity: build up in adipose tissue; more likely to be toxic

Question 5

define: bioavailability

Answer 5

Bioavailability: Rate and extent to which a nutrient is absorbed and used in the body

Question 6

Fill in the blank: _____ of vitamins in food are absorbed

- What is the absorption of vitamins affected by (5)?

Answer 6

40-90%

• Efficiency of digestion and time of transit through the digestive tract
• Previous nutrient intake and nutrition status
• Other foods consumed at the same time (medication too)
• Methods of preparation
• Sources of the nutrient (foods verses supplements)

Question 7

Vitamins can be destroyed by what (3)?

Answer 7

• Heat
• UV light
• Oxidation

Question 8

How can we prevent the loss of vitamins in our food?

Answer 8

• Refrigeration of fruits and vegetables
• Storing cut vegetables, fruits, and juices in airtight containers to avoid oxidation
• Wash fruits and vegetables before cutting
• Steam vegetables in small amounts of water, avoid over cooking

Question 9

Define: primary deficiency

Answer 9

Primary deficiency: intake of vitamins decreased

Question 10

Define: secondary deficiency

Answer 10

Secondary deficiency: intake of vitamins are normal but absorption is decreased

Question 11

What food group offers the largest variety of vitamins

Answer 11

meat and alternatives

Question 12

Which type of vitamin can be absorbed directly into the blood. Why can’t the other type be absorbed directly?

Answer 12

water soluble vitamins; Fat soluble are too large to be filtered in kidney capillaries

Question 13

Describe vitamin digestion in the mouth

Answer 13

Mouth: mechanical digestion releases vitamins in food

Question 14

Describe vitamin digestion in the stomach

Answer 14

Stomach: digestion of food releases vitamins; some niacin is absorbed here

Question 15

Describe vitamin digestion in the gallbladder

Answer 15

Gallbladder: releases bile which emulsifies fat and helps absorb fat soluble vitamins

Question 16

Describe vitamin digestion in the pancreas

Answer 16

Pancreas: secretes digestive enzymes that aid in the release of vitamins from food

Question 17

Describe vitamin digestion in the small intestine

Answer 17

Small intestine: fat soluble vitamins are incorporated into micelles then absorbed by simple diffusion. Once they are inside the mucosal cells fat soluble vitamins are packaged into chylomicrons which enter the lymph before passing into the blood. Water soluble vitamins are absorbed from the small intestine directly into the blood. May depend on energy requiring transport systems or must bind to specific molecules in the gastrointestinal tract to be absorbed. Vitamin B12 is absorbed in the lower portion of the small intestines

Question 18

Describe vitamin digestion in the large intestine

Answer 18

Large intestine: bacteria synthesizes small amounts of vitamins, some of which are absorbed

Question 19

Fill in the blank: Vitamins, except _______, must be separated out from other food components during digestion before absorption

Answer 19

fat soluble vitamins,

Question 20

Fill in the blank: ___ vitamins act as coenzymes for energy metabolism (cellular respiration)

Answer 20

8

Question 21

Do vitamins provide energy to the body?

Answer 21

No: they help in the process that converts food energy; they themselves are not a fuel for the body and therefore do not provide any calories

Question 22

What vitamins function primarily as coenzymes?

Answer 22

B vitamins

Question 23

Vitamin B1: Thiamin

• 2 sources
• 2 functions
• Deficiency signs
• 1 symptom of toxicity

Answer 23

Vitamin B1: Thiamin
- Sources: enriched grains, pork, seeds nuts
- Function: role in muscular contraction, nerve conduction, and required for ATP synthesis (part of coenzyme: thiamine pyrophosphate; this is required for the citric acid cycle)
Deficiency signs:
- Wernicke/Korsakoff Syndrome: short term memory loss, confusion, disorientation, and changes in eye movements
- Wet BeriBeri: from the sinhalese word meaning “I cannot/ extreme weakness”, negatively impacts cardiovascular system and can lead to heart failure;
- Dry BeriBeri: negatively impacts the nervous and muscular systems potentially leading to muscle paralysis
- causes of deficiency: eating only refined grains, chemotherapy, alcoholism
- no known toxicity

Question 24

How does alcoholism cause deficiency

Answer 24

• impairs absorption by blocking it in the small intestine

Question 25

Vitamin B2: Riboflavin - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 25

- Source: dairy products, whole and enriched grains, dark green vegetables, meat, fish, eggs, yeast - Function: helps form 2 coenzymes: flavin mononucleotide and flavin adenine dinucleotide (FMN and FAD). They are both involved in conversion of amino acid tryptophan to niacin and maintaining appropriate homocysteine levels - Toxicity: rare; most people in developed world get 2x the recommended - Deficiency signs: ariboflavinosis: skin disorders, swelling in the mouth and throat, dry and cracked lips, red eyes, hair loss; More common in vegetarians and those with hormonal abnormalities

Question 26

Vitamin B3: Niacin - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 26

- Source: beef, chicken, fish, fruits and vegetables, peanuts, legumes, whole and enriched grains, fortified bread - Function: Forms the coenzyme nicotinamide adenine dinucleotide (NAD). NAD is an electron transporter for the electron transport chain. NAD is required for more than 400 enzymes. It is involved in more reactions than any other vitamin - Toxicity signs: niacin flush: flushing, itching, burning of skin low blood pressure, fatigue, insulin resistance - Deficiency signs: Pellagra: dermatitis, diarrhea, dementia, death (4Ds)

Question 27

Vitamin B5: Pantothenic Acid - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 27

- Source: beef, poultry, seafood, organ meats like liver and kidney, milk, vegetables, shiitake mushrooms, - Function: helps form coenzymes A (required for acetyl CoA); essential for energy metabolism - Toxicity and deficiency signs: (has not been proven to be found in humans; only animals)

Question 28

Vitamin B6: Pyridoxine - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 28

- Source: pork, poultry, peanuts - Function: act as a coenzyme in more than 100 reactions (ex: energy metabolism). Forms neurotransmitters serotonin and norepinephrine. Lowers homocysteine levels by converting it to cysteine. Also involved in white blood cell function - Toxicity signs: rare; due to over supplementation (>1000mg/d); promotes loss of control over body movements - Deficiency signs: rare; usually in combination with other B vitamin deficiencies; alcoholics are at risk; microcytic anemia: fatigue, lethargy

Question 29

Vitamin B7: Biotin - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 29

- Source: organ meats, eggs, fish, meat, seeds, nuts - Function: coenzymes for energy metabolism, involved in cell signalling, DNA structure and DNA function - Toxicity signs: rare, over supplementation can compromise laboratory test results - Deficiency signs: rare; may occur with genetic disorder called biotinidase deficiency: hair loss, red eyes, rashes. Severe deficiency can progress to seizures, depression, and muscle disorders

Question 30

Vitamin B9: Folate/Folic Acid - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 30

- Source: leafy green vegetables (kale, spinach), legumes, seeds, enriched grains and orange juice - Function: coenzyme in DNA/RNA synthesis and amino acid metabolism; therefore it is particularly important for rapidly dividing cells like the intestines, skin, embryonic and fetal tissues, and bone marrow. Also involved in conversion of homocysteine to methionine - Toxicity signs: rare; nausea, bloating, decreased appetite, difficulty sleeping Toxicity can mask B12 deficiency since it prevents megaloblastic anemia - Deficiency signs: pregnant women and alcoholics are at risk; deficiency can lead to neural tube defects: can cause miscarriage and birth defects such as spina bifida and anencephaly. - Can also lead to macrocytic/ megaloblastic anemia: red blood cells are immature, large, misshapen, and unable to properly carry oxygen leading to tiredness, weakness, and heart irregularities. This is because deficiency negatively affects DNA synthesis so red blood cells don’t divide and don’t mature properly. Macrocytic/megaloblastic anemia is the most obvious sign of folate deficiency in adults.

Question 31

What is the most common symptom of anemia

Answer 31

persistent weakness

Question 32

Vitamin B12: Cobalamin - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 32

- Source: only in animal sources except nutrition yeast; supplementation recommended for vegans and vegetarians - Function: required for DNA synthesis, red blood cell formation, brain function, acts as a coenzyme for conversion of homocysteine to methionine - Toxicity signs: rare; however B12 can interact with certain medications - Deficiency signs (: megaloblastic anemia; poor balance issues, depression, poor memory, confusions

Question 33

Vitamin C: Ascorbic Acid - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 33

- Source: citrus fruits, vegetables - Function: critical for the synthesis/ maintenance of collagen which is the base of all connective tissue and promotes integrity of the skin; also involved in protein metabolism and iron absorption; serves as an antioxidant as it protects against oxidative damage by free radicals - Toxicity signs: >2000mg/day can promote gastrointestinal symptoms - Deficiency signs: rare. Scurvy: bleeding gums, fatigue, poor collagen formation, bone fragility and pain

Question 34

carotenoids

Answer 34

vitamers of provitamin A that must be converted into retinoids

Question 35

What are the active forms of vitamin A

Answer 35

retinal and retinoic acid

Question 36

Sources of provitamin | a

Answer 36

carrots, leafy greens, broccoli, plant products;

Question 37

Sources of preformed vitamin | a

Answer 37

liver, dairy products, fish, eggs, animal products

Question 38

Functions of vitamin A

Answer 38

Function: part of a visual pigment in the retina of the eye which helps interpret visual stimuli, cornea health, epithelial tissue health. Gene function: when genes are turned on and off; immune function: contributes to formation of infection fighting T cells; carotenoid form (plants) function as an antioxidant.

Question 39

Vitamin A toxicity

Answer 39

Toxicity: carotenoids may turn skin slightly orange. Preformed vitamin A toxicity can cause elevated pressure around brain, dizziness, nausea, liver toxicity, headaches, bone pain and can be fatal

Question 40

Vitamin A deficiency

Answer 40

Deficiency: rare in developed countries; linked to poverty and low diet variability. Xerophthalmia: dryness of the eye and affects tear formation; can lead to breaks in the cornea and blindness; Night blindness: early stage of xerophthalmia

Question 41

Vitamin A deficiency

Answer 41

Deficiency: rare in developed countries; linked to poverty and low diet variability. Xerophthalmia: dryness of the eye and affects tear formation; can lead to breaks in the cornea and blindness; Night blindness: early stage of xerophthalmia

Question 42

Vitamin D - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 42

- Source: sunlight, egg yolks, oily fish (tuna, salmon), fortified foods (milk), liver - Function: calcium homeostasis (increases calcium, phosphorus, and magnesium absorption); plays a role in cellular growth, immune function, and inflammation reduction - Toxicity: toxicity from food is rare and typically due to over-supplementation; can promote anorexia, weight loss, increased urination, irregular heart rhythms, can also increase blood calcium, can harden blood vessels, eyes, and negatively impact kidneys and heart - Deficiency: common; due to inadequate dietary consumption and/or limited sun exposure; can promote rickets in children (bones don’t calcify and bend under our weight) and osteomalacia in adults (softening of the bones). Osteomalacia can progress to osteoporosis

Question 43

Fill in the blank: When calcium levels drop, _____________ is released and activates vitamin D at the kidney. What 3 things does this activated vitamin D do?

Answer 43

- parathyroid hormone (PTH) - Promotes Ca2+ absorption at SI - Reduces Ca2+ excretion at the kidneys - Mobilizes Ca2+ from bone

Question 44

Vitamin D is inactive until modified by what?

Answer 44

the liver and kidneys

Question 45

What is the relation between vitamin D and the sun?

Answer 45

You do not absorb vitamin D from the sun; light energy hits the skin and triggers the reaction that helps synthesize an inactive form of vitamin D from precursors

Question 46

Vitamin E - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 46

Source: vegetable oils, seeds, nuts Function: known for antioxidant role (may promote reduced risk of chronic diseases); involved in immune function and cell signalling; Adequate dietary vitamin E is recommended over supplements Toxicity: due to over supplementation and increases mortality rate; can be linked to lung illnesses in those that vape. High levels of vitamin E were found in the blood of individuals with vaping related lung issues such as difficulty breathing, chest pain, fatigue, and vomiting Deficiency: lead to break down of cell membranes; RBCs and nerve tissue at high risk. Can lead to hemolytic anemia (common in premature infants). Deficiency is rare and typically due to compromised fat absorption; symptoms: peripheral neuropathy, movement difficulties, muscle disorders, impaired immune response

Question 47

Vitamin K - Remember 2 sources - 2 functions - 1 symptom of deficiency - 1 symptom of toxicity

Answer 47

- Source: vegetable oils, leafy greens, can be synthesized by intestinal bacteria - Function: necessary for production of clotting proteins; example: prothrombin synthesis. Prothrombin is needed to form sticky fibrin fibres to help RBCS clump together - Toxicity: has not been observed yet - Deficiency: rare; found in newborns with compromised absorption and those who overuse antibiotics; excessive bleeding, hemorrhaging, newborns get a shot of vitamin K to prevent this

Question 48

What is Warfarin and what is it prescribed for?

Answer 48

Warfarin is an anticoagulant (blood thinner) that blocks vitamin K- dependent coagulation pathway. Prescribed for those at high risk for heart attacks and strokes (decreases risk of clotting)

Question 49

What kind of product is a vitamin-infused beverage?

Answer 49

- natural health product; does not have to contain a nutrient fact box

Question 50

Why aren't vitamin infused beverages all that they seem?

Answer 50

- most Canadians are not deficient in vitamins contained in vitamin water - have a lot of added sugar - false sense of security about health

Question 51

Give the recommended dietary supplement(s) for this group of people: vegans

Answer 51

B12, vitamin D, Ca2+

Question 52

Give the recommended dietary supplement(s) for this group of people: infants and children

Answer 52

fluoride, vitamin D, iron

Question 53

Give the recommended dietary supplement(s) for this group of people: child planning/ pregnant women

Answer 53

folate

Question 54

Give the recommended dietary supplement(s) for this group of people: older adults

Answer 54

B12, vitamin D

Question 55

Give the recommended dietary supplement(s) for this group of people: dark-skinned individuals

Answer 55

vitamin D

Question 56

Give the recommended dietary supplement(s) for this group of people: smokers

Answer 56

vitamin C

Question 57

Give the recommended dietary supplement(s) for this group of people: alcohol users

Answer 57

B vitamins