Review Exam 5 Flashcards
Precursor
Form they are in food is an inactive form, known as a precursor.
Once consumed it is converted to it’s active form
Consideration has to be made for the amount of active vitamin consumed and the potential amount from precursor.
Bioavailability
Rate and extent to which a nutrient is absorbed and used.
Depends on:
Efficiency of digestion and time of transit through GI tract.
Previous nutrient intake and nutrition status
Other foods that may inhibit or enhance absorption
Method of food preparation
Source – whether natural or synthetic
General characteristics of fat and water-soluble vitamins
See PPT Chapter 11 Slide 2
Primary function of B vitamins
B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism
Function of a coenzyme
Helpers to the vitamin
Beriberi
Thiamin Deficiency disease
Beriberi
Wet, with edema
Dry, with muscle wasting
Richest food sources of thiamin
Whole grain, fortified, or enriched grain products
Moderate amounts in all nutritious food
Pork – most significant
Best cooking method for food sources of thiamin
Steam or microwave
Function of the coenzyme form of Riboflavin
Part of coenzymes FMN (flavin mononucleotide) and FAD (flavin adenine dinucleotide) used in energy metabolism.
Riboflavin and UV light
Easily destroyed by ultraviolet light and irradiation
Niacin and Tryptophan
Carries electrons to the ETC
significant source is protein
Precursor: dietary tryptophan
Niacin flush
Painful flush, hives, and rash (“niacin flush”)
Protein found in what food inhibits absorption of Biotin
Egg whites
Deficiency disease of Riboflavin
ariboflavinosis
Vitamin thought to combat PMS
Folate
Best food source of Riboflavin
Significant sources Milk products (yogurt, cheese) Enriched or whole grains Liver Dark Green veggies
Pellagra
Deficiency disease: Pellagra
Deficiency symptoms
Remember the 4 D’s
Dermatitis, Diarrhea, Dementia, Death
Abdominal pain, vomiting
Inflamed, swollen, smooth, bright red tongue
Depression, apathy, fatigue, loss of memory, headache
Bilateral symmetrical rash on areas exposed to sunlight
Vitamin synthesized by intestinal bacteria
Biotin, K
Vitamin that is part of coenzyme A
Pantothenic Acid / Vitamin B
Vitamin that reduces the risk of neural tube defects
Folate
Most common neural tube defect
Spina bifida
Function shared by B12 and Folate
DNA synthesis
Vitamin that is bound to glutamic acid molecules in food
Folate glutamic
Bioavailability of dietary and supplemental folate
Bioavailability ranges from 50% with foods to 100% from supplements
Deficiency symptoms of Folate
Anemia (large-cell type) Megaloblastic anemia
Smooth, red tongue
Mental confusion, weakness, fatigue, irritability, headache
Intrinsic Factor
substance secreted by stomach to help absorb Vit B 12
Likely reason for a B12 deficiency
B12 deficiency caused by atrophic gastritis and lack of intrinsic factor is pernicious anemia
Deficiency symptoms of B12
Anemia (large-cell type)
Fatigue, degeneration of peripheral nerves progressing to paralysis
If folate is given when B 12 is deficient neurological symptoms may persist.
Groups at risk for B12 deficiency
older people
Pernicious anemia
deficiency of Vit B12
Main functions of Vitamin C
Collagen synthesis
Strengthens blood vessel walls, forms scar tissue, provides matrix for bone growth
Antioxidant
Thyroxin synthesis – important in metabolism
Amino acid metabolism
Strengthens resistance to infection
Helps in absorption of iron
Vit C deficiency signs and symptoms
scurvy
Anemia (small-cell type)
Atherosclerotic plaques
Pinpoint hemorrhages, bone fragility, joint pain
Poor wound healing, frequent infections, bleeding gums, loosened teeth
Muscle degeneration and pain, hysteria, depression, rough skin, blotchy bruises
Foods rich in Vit C
Citrus fruits Cabbage-type vegetables, dark green vegetables (such as bell peppers and broccoli) Cantaloupe, strawberries Lettuce, tomatoes, potatoes Papayas, mangoes
Know alternative names for vitamins
See cards
Different forms of Vit A
Retinoids
Carotenoids
Functions of Vitamin A
Promoting Vision
Participating in Protein Synthesis and cell differentiation (maintaining the health of epithelial tissues and the skin).
Supporting Reproduction and Growth
Deficiency signs and symptoms of Vitamin A
Night blindness, corneal drying (xerosis), triangular gray spots on eye (Bitot’s spots), softening of the cornea (keratomalacia), and corneal degeneration and blindness (xerophthalmia)
Deficiency symptoms (continued)
Impaired immunity (infections)
Plugging of hair follicles with keratin, forming white lumps (hyperkaratosis)
Retinol-Binding-Protein
Special transport protein that picks up Vitamin A from the liver where it is stored and carries it to the bloodstream.
Features of Accutane
Vitamin A will not cure acne.
Accutane made from Vitamin A, chemically different
Highly toxic especially for pregnant women.
Vitamins that are antioxidants
Vitamins C, E & A(beta carotene)
Organ that stores fat-soluble vitamins
Liver
Toxicity of Beta-Carotene
Skin discoloration – beta carotene
Food sources of Vitamin A
Vitamin A in foods
The colors of vitamin A foods
Vitamin A-poor fast foods
Vitamin A-rich liver
Retinol: fortified milk, cheese, cream, butter, fortified margarine, eggs, liver
Beta-carotene: spinach and other dark leafy greens; broccoli, deep orange fruits (apricots, cantaloupe) and vegetables (squash, carrots, sweet potatoes, pumpkin)
Precursor to Vitamin D
Precursor is the body’s own Cholesterol
Organs that help synthesize Vitamin D
Liver & Kidneys
Deficiency diseases of Vitamin D
Rickets - Children
Inadequate calcification, resulting in misshapen bones (bowing of legs)
Enlargement of ends of long bones (knees, wrists)
Deformities of ribs (bowed, with beads or knobs)
Delayed closing of fontanel, resulting in rapid enlargement of head
Lax muscles resulting in protrusion of abdomen
Muscle spasms
Osteomalacia- Adults; softening of the bones.
Loss of calcium, resulting in soft, flexible, brittle, and deformed bones
Progressive weakness
Pain in pelvis, lower back, and legs
Food sources of Vitamin D
Synthesized in the body with the help of sunlight
Fortified milk, margarine, butter, cereals, and chocolate mixes
Veal, beef, egg yolks, liver, fatty fish (herring, salmon, sardines) and their oils
Main function of Vitamin E
An Antioxidant – Stops the chain reactions of free radicals from producing other free radicals.
Protects PUFA and Vitamin A from oxidation
Protects LDL from oxidation and so reduces the risk of heart disease.
Deficiency disease of Vitamin E
Deficiency from inadequate dietary intake is rare, deficiency associated with disease of fat malabsorption
Red blood cells break open and spill their contents – Erthrocyte Hemolysis can lead to hemolytic anemia
Premature Infants
Nerve damage – involving spinal cord and retina of the eye
Food source of Vitamin E
Polyunsaturated plant oils (margarine, salad dressings, shortenings)
Leafy green vegetables, wheat germ, whole grains, liver, egg yolks, nuts, seeds
Precursor to Vitamin A
Beta-carotene
Blood clotting protein that need Vit K to be synthesized
slide process with prothromin look at slide***
Vitamins that are synthesized in the body (2 of them)
bioten and K
Food sources of Vitamin K
Bacterial synthesis in the digestive tract
Liver
Leafy green vegetables, cabbage-type vegetables
Milk
Vitamin injected at birth in newborns
Vit K
Free radicals
Free radicals are molecules with one or more unpaired electrons, highly unstable, highly reactive.
Deficiency disease of Vitamin E
Malabsorption
in pregnancy during 3rd trimester it causes them to come out premature Erthrocyte Hemolysis can lead to hemolytic anemia
Function of Vitamin K
Synthesis of blood-clotting proteins
Activates prothrombin – a precursor of thrombin
