Chapter 7 Vitamins Flashcards
What are precursors/provitamins?
Transform chemically to one or more active vitamin forms
What does a measure of vitamin in a food include?
Vitamin and the vitamin activity potential from its precursors
What is Bioavailability?
The rate and the extent to which a nutrient is absorbed and used
What is malnutrition?
Any condition caused by excess or deficient food energy or nutrient intake or by an imbalance of nutrients
Undernutrition?
Deficient in energy of nutrients
Overnutrition?
Excess energy or nutrients
Subclinical Deficiency?
A deficiency in the early stages, before the outward signs have appeared
What are the fat-soluble vitamins? x4
A
D
E
K
What are the general characteristics of fat-soluble vitamins? x5
-Absorbed into the lymph
-Require Bile for absorption
-Travel in blood in association with protein carriers
-Stored in tissues, Lier and Fatty Tissues
-May be toxic in excess
What are the Water-Soluble Vitamins?
B vitamins
Vit C
What are the 5 characteristics of Water-Soluble Vitamins?
-Absorbed directly into the bloodstream
-Travel feely in bloodstream
-Most are not stored to any great extent
-Excess excreted in urine
-Lower risk of toxicity than fat-soluble vitamins
What vitamin can the body survive for weeks without consuming?
Fat Soluble
What two fat-soluble vitamins cane easily reach toxic levels?
Vit A and D
What foods are fat soluble?
Fats and Oils
What are the 3 forms of active Vit A in the body?
Retinol
Retinal
Retinoic Acid
What is the Vit A plant-derived precursor?
Beta-Carotene
What are the 7 Roles of Vitamin A?
-Vision
-Gene Expression
-Maintenance of Body Linings and Skin
-Immunity
-Growth of Bones and the Body
-Normal Development of Cells
-Critical Importance to reproduction
What is the vitamin-A containing pigment in eye?
Rhodopsin
How is vit A used in the eye?
-Retina contains light-sensitive cells
-light bleaches rhodopsin
-rhodopsin breaks off Vit A, initiating impulse
-Vit A reunites with with pigment
What occurs to eyesight if Vit A runs low in terms of Night Blindness?
-Lag occurs before the eye can see again after a flash of bright light
-Vit A and Pigment do not reunite as fast due to less Vit A
What occurs to eyesight if Vit A runs low in terms of Keratin?
Keratin Accumulation of the cornea occurs.
-Leads to xerosis and xerophthalmia causing permanent blindness
How does skin and body linings use Vit A? x2
-Needed by Epithelial Tissues
-Promotes Cell Differentiation
How does vit A control gene expression?
Retinoic Acid activates or deactivates certain genes, thereby affecting protein production.
How does Vit A contribute to immunity?
-Plays a role in regulation that produce immune system proteins
-Deficiency can lead to a spiral of malnutrition and infection
How does Vit A contribute to Growth?
Assists in growth of bone and teeth - needed in the dismantling step of old bone structure
What are the 4 things that may occurs with Vit A deficiency?
Cell differentiation and Maturation are impaired
-Failure of mucus-producing cells to produce mucus
-A subsequent increase in keratin-producing cells
-Tissues more vulnerable to infection
What is the best way to help prevent/ help Vit A deficiency?
Vit A Supplementation
What causes Vit A Toxicity?
Supplements or Fortified Foods
What are common results of Vit A Toxicity?
May Weaken Bones
Bone and Joint Pain
Abdominal Pain
Stunted Growth
Liver Damage
What are early symptoms of Vit A toxicity?
Loss of Appetite
Blurred Vision
Growth Failure in Children
Headache
Skin Itching
Irritability
What are long-term symptoms of Vit A Toxicity?
Bone Weaking and Hip Fracture
What are 3 Groups of People who are targeted for Vit A Toxicity?
-Pregnant Women (Use supplements)
-Children who mistake chewable vit pills for candy
-Adolescents who take large doses for acne (Accutane = Vit A but Vit A supplements do not help acne)
T or F Beta Carotene Causes Vit A Toxicity
False
Can turn yellow/orange due to deposition in subcutaneous fat
What is the most abundant of the carotenoid precursors
Beta-Carotene
How is Vit A Activity for Vit A precursors measured?
Retinol Activity Equivalents (RAE)
What is 12 mcgs of beta-carotene equilivant to?
1 Microgram (RAE)
Why are deep orange fruits and veggies and dark green veggies good for eyesight?
Rich in Beta-Carotene
(Doesn’t improve vision if Vit A is adequate already)
Lack of foods rich in _____ increases the risk of macular degeneration?
Beta-Carotene
Elevated Beta-Carotene levels in food and blood _____ cancer list?
Reduce
T or F Beta-Carotene supplements show the same benefits than receiving it from food.
False, cancer benefit not seen
-Supplements associated with increased risk of cancer in smokers
What is a major dietary antioxidants?
Beta-Carotene
Where is Vit A Found?
Foods of animal origin
Where is Beta-Carotene found?
Plants
3 sources of good vitamin A in foods?
1)Liver and Fish Oil
2)Fortified Milk and Milk Products
3)Eggs
Is Vitamin D essential
No The body can make all it needs with the help of sunlight
-Although many borders on vit D insufficiency
What are the two roles of Vitamin D?
-Regulation of blood calcium and phosphorus levels and maintains bone integrity
-Functions as a hormone
How does vitamin D regulate calcium?
When more calcium is needed it raises blood calcium levels
-Promotes Ca absorption
-Promotes Ca retention by kidney
-Draws Ca from bone
What diseases does Vit D deficiency promote?
1)High BP
2)Cancer
3)T1D
4)heart Diseases
5)Rheumatoid Arthritis
6)Inflammatory Bowel Disease
7)Multiple Sclerosis
What is Rickets?
Vit D deficiency disease in children
-Abnormal Bone Growth
-Bowed Legs, Outward-Bowed Chest, Knobs on Ribs
What is the adult form of rickets?
Osteomalacia
Who is most susceptible to osteomalacia?
Women with
1)Low Ca Intake
2)Little Sun Exposure
3)Who go through repeated pregnancies and lactation periods
Too much Vit D is a danger to soft tissue? T or F
True, continued overdoses cause high blood Ca level, forcing Ca to be deposited in soft tissues
What is the most toxic of all vitamins in excess?
Vit D
How is Vit D made from sunlight?
UV exposure to a cholesterol compound in the skin transforms it into a vitamin D precursor which is absorbed in the blood
-The liver and kidneys convert precursor to active from of Vit D
Skin synthesis of Vit D can add to toxicity?
False
Sunscreen with SPF above ___ can prevent Vit D syntesis?
8 (including)
Health Canada for Vit D consumption?
Canadian over 50: 400 IU supplement/day
Why may recommendation for Vit D intake increase with age?
Less sunlight exposure, higher risk for osteoporisis
What are 6 sources of Vit D?
Sunlight
Small Amounts of butter, cream and fortified margarine
Fortified Milk
Egg Yolks, liver, fatty fish, and fish oil
-Only certain fortified plants exists
Mushrooms
No Osteroprosis recommendation? 19-50
400-1000 IU daily
No Osteroprosis recommendation? 50+
800-2000 IU daily
Osteoprosis high risk reccomendation?
800 IU-2000 IU regardless of age
What are the 4 tocopherol compounds in Vit E?
1)Alpha
2)Beta
3)Gamma
4)Delta
What tocopherol is the gold standard for Vitamin E activity?
Alpha-Tocopherol
How is Vit E important in preventing oxidative damage of cells?
Antioxidant
-Vit E is preferentially oxidized, thus preventing free radicals
How does oxidative damage occur/result?
Free Radicals
What are the 2 key spots important to Vit E antioxidant effect?
-Lungs: cells are exposed to high O2 concentrations
-Protects red and white blood cells
What are 3 roles of Vit E?
1)Antioxidant
2)Immunity
3)Nerve Development
T or F Vit E supplements always provide health benefits?
F: Unless deficient
How do infants have Vit E deficiency?
Born before the transfer of Vit E. from mother to infant