fnu 203 chapter 9

what is the literal meaning of vitamin?

vita- necessary for life / amine- type of nitrogen- containing substance. the term vitamine was changed to vitamin after it was determined that there were several kinds of these substances and not all were amines

list at least three criteria used to designate a substance as a vitamin

cannot be synthesized by the body or make enough to maintain good health, occurs naturally in foods, deficiency disorder occurs if substance is missing from the body or is not properly metabolized, health is restored by supplying missing substance

identify the four- fat soluble vitamins

A, D, E, K

describe how antioxidants protect against free- radical damage

antioxidants give up electrons to free radicals to protect cells. they protect molecules in cells, such as polyunsaturated fatty acids and DNA, from being oxidized.

list at least three factors that affect the bioavailability of a vitamin

life stage and individual's nutrient status, changes to GI transit time, health conditions affecting absorption of fat, food processing and preparation techniques, source of vitamin

discuss at least five ways to preserve the vitamin content of fruits and veggies during food preparation and storage

store fresh produce at temperatures near freezing, in high humidity, away from air, avoid exposure to excessive heat, alkaline substances, light, and air, cook vegetables in small amounts of water, using quick cook methods (stir- frying and steaming), consume highly perishable produce like berries and leafy veggies soon after harvest or purchase

what feature makes vitamins A, D, E, and K soluble in fat?

all include a hydrocarbon chain

major functions of vitamin A

participates in cell production, growth, development, function, maintenance, and vision

major functions of vitamin D

regulation of calcium and maintenance of phosphorus levels in the blood, adn the production and maintenance of healthy bones

major functions of vitamin K

functions as a cofactor in a number of biochemical pathways, including blood clotting, (K2)- bone metabolism and cardiovascular health, regulates calcium in the body and prevents the deposition of calcium in soft tissues, such as blood vessels

major functions of vitamin E

protects polyunsaturated fatty acids in cell membranes from being damaged by free radicals, other roles include: maintaining nervous tissue and immune system function

name the three active forms of vitamin A

retinol, retinal, retinoic acid

good food sources of preformed vitamin A

liver, butter, fish liver oils, eggs

good food sources of beta- carotene

carrots, spinach, other leafy greens, pumpkin, sweet potatoes, broccoli, mangoes, cantaloupe

explain the role of vitamin A in preventing night blindness

rods and cones need vitamin A to function properly, specifically retinol. rods convert retinol to retinal. Retinal binds to protein opsin to form rhodopsin in dark conditions.

good food sources of vitamin D

salmon, herring, catfish, vitamin D fortified- milk, cereal, orange juice, margarine

what groups of people are at the greatest risk for rickets and osteomalacia, and why?

adults confined indoors or almost fully covered when outside

what form of vitamin E has the highest biological activity?

alpha- tocopherol

good food sources of vitamin E

sunflower seeds, almonds, plant oils and products made from them, fish, whole grains, nuts and seeds, certain vegetables

explain the consequences of a vitamin E deficiency

nerve damage, loss of neuromuscular control, blindness, reduced function of immune system

identify the three forms of vitamin K and their relationship to each other

phylloquinone: vitamin K1, menaquinone: vitamin K2, menadione: can be converted into menaquinone in the body

describe the role of vitamin K in clotting blood

when vitamin K1 is unavailable, the blood- clotting factors are inactive, and the blood does not clot effectively

good food sources of vitamin K

green leafy vegetables, broccoli, green beans, egg yolks, butter, certain cheeses, liver, beef, some fermented foods

explain the consequences of vitamin K deficiency

abnormal blood clotting and bleeding

explain the consequence of vitamin K toxicity

antagonistic reaction to vitamin E

qualities of fat- soluble vitamins as it pertains to solubility and storage

soluble in fat, stored in the body (esp. liver)

qualities of water- soluble vitamins as it pertains to solubility and storage

soluble in water, not stored to any significant degree