Download - Chapter Eight: The Vitamins
Chapter Eight: The Vitamins Define vitamins and identify their
characteristics Differentiate between the two
classes of vitamins Name the fat-soluble vitamins
Major functions Deficiency results Significant food sources of each
Vitamins, cntd. Differentiate between active and
precursor forms of Vitamin A Describe the relationship between
Vitamin and Iron Absorption
Characteristics of Vitamins Occur in food in much smaller
amounts No energy contributions—no
kcalories Help and facilitate body processes Necessary for health but not
CURE--ALLS
Vitamins Defined Potent, essential, non-caloric,
organic nutrients Measured in milligrams or
micrograms Assist enzymes in the release of
energy from the energy nutrients Fat soluble and Water soluble forms Bioavailability—quantity provided
and amount absorbed
Fat-Soluble Vitamins Vitamins A, D, E, and K
Stored in Liver and Fatty Tissues Excess not excreted—can be toxic Travel in the blood with protein Not necessary to replenish daily
Vitamin A (Retinol and Beta-Carotene) Metabolic Functions--Antioxidant
Vitamin A, cntd. Vision—part of the pigment of the eye
that allows eye to adjust to changing light levels
Health of skin and linings of organs—health of epithelial cells that secrete mucus
Defense against infection Toxicity: animal sources and high
dosage supplements
Vitamin A, contd. Active vs. Precursor form
Active form (retinol) found in animal sources—fat of animals
Precursor form (beta-carotene) found in deep green and dark yellow fruits and vegetables—activate only when needed
Deficiency: Night Blindness and dryness of epithelial cells
Precursor Form of Vitamin A
Vitamin D (Calciferol) Not totally essential because the body can
make it from sunlight on the skin Functions: Makes calcium and phosphorus
available in blood to harden bones (bone-making and maintenance team)
Deficiencies: Rickets in children and Osteomalacia mostly in child-bearing women
Osteoporosis—impairs calcium absorption Sources: Eggs, liver, fish oils, and fortified
milk
Vitamin D Deficiency--Rickets
Vitamin E (Tocopherol) Function: Anti-oxidant—defends
against oxidation—especially polyunsaturated fatty acids
Heart health and protection against fibrocystic disease
Deficiency: Erythrocite hemolysis—breaking open of red blood cells
Toxicity: above 800 mg/RDA 8-10 mg
Vitamin E, contd. Sources:
Widespread in foods Vegetable oils, fruits, vegetables and
grains
Vitamin K Synthesis is possible in the intestinal
tract, but not sole source of it—not found in sterile GI tract (newborns)
Antibiotics can interfere with synthesis Function: necessary for normal blood
clotting Sources: green leafy vegetables,
cabbage family, liver, meats, milk, eggs, cereal and fruits
Water-Soluble Vitamins No accumulation in body tissues
from foods—large doses of supplements can be toxic
Easily absorbed and excreted in urine when there is excess
Need good sources daily
Vitamin B Complex Coenzymes involved in catabolic
and anabolic reactions in the body Thiamin(B1), Niacin(B3),
Riboflavin(B2), Pantothenic Acid & Biotin Involved in catabolic reactions Needed for the release of energy from
the energy nutrients
Riboflavin Source
Vitamin B Complex, contd. Vitamin B6
Anabolic reaction—synthesis of nonessential amino acids
Can minimize heart disease risk Folate
Anabolic reaction—new cell synthesis—especially of nervous system and spinal cord of developing fetus
Deficiency during pregnancy can lead to spina bifida—incomplete formation of spinal column
Spina Bifida
Vitamin B Complex, cntd. Vitamin B12 (Cyanocobalamin)
Anabolic reaction—formation of new cells, especially red blood cells
Deficiency is anemia
Vitamin B Complex, cntd. Deficiency diseases
Thiamin—Beriberi Niacin--Pellagra
Fortification and Enrichment of staple foods—especially cereals and grain products has reduced deficiencies of B Vitamins
Sources B Complex Vitamins
B Vitamin Complex, cntd. Good sources are widespread in
foods—whole foods best sources Light and heat sensitive—can be
lost in cooking liquid Folate: Best sources are liver,
legumes, and green leafy vegetables (foliage)
Vitamin B12: Only available in animal products
Vitamin C (Ascorbic Acid) Function: Necessary for the formation
of the protein collagen—protein of connective tissue (wound healing); also an antioxidant for water solubles
Deficiency: Scurvy—bleeding gums, pinpoint hemorrhages, bruising easily, failure of wounds to heal
RDA: 75 -100 mg Increases during pregnancy and lactation
Vitamin C, cntd. Stress, infections and smoking
increase needs up to 100 mg Oral contraceptives increase needs
Sources: Fruits and Vegetable groups only—especially citrus fruits, strawberries, and cruciferous vegetables
Sources of Vitamin C
Cruciferous Vegetables
Vitamin Supplements—Are They Necessary? Good diet including a variety of
foods should supply vitamins & minerals needed
Those who may need them Low kcalorie dieters Depressed appetite—illness, age Illnesses that impair absorption Heavy blood losses—menstruation
(Iron)
Vitamin Supplements, cntd.
During pregnancy and lactation—especially iron and folate
Strict (vegan) vegetarians Newborn infants Recovery from infection or surgery Breast fed infants
Best if prescribed by R.D. or M.D.—multivitamin usually safe
Phytochemicals Found in foods—impart tastes, aromas,
colors, etc. Act as antioxidants and suppress
diseases Diets rich in whole grains, legumes,
vegetables and fruits can be protective against heart disease and cancer
Eat colorful foods—orange, red and green
Test Questions The psychological desire to eat is
referred to as: Satiety Appetite Hunger Obesity
Obese people have much more lipoprotein lipase activity than lean people True False
Which of the following is NOT a fat-soluble vitamin? A E K C D
Which vitamin is present only in foods of animal origin? Riboflavin Vitamin B12 Pantothenic acid The inactive form of Vitamin A