nutrition chapter 12
which fat soluble vitamins are not readily excreted from the body
vitamin a,d,k
the cones are responsible for vision during what light?
A) bright light #Vitamin A (as retinal) is needed in the retina of the eye to turn visual light into nerve signals to the brain. The sensory elements of the retina consist of the rods and cones. Rods are responsible for the visual processes that occur in dim light, translating objects into black-and-white images and detecting motion. Cones are responsible for the visual processes occurring under bright light, translating objects into color images.
what is the RDA for vitamin A for adult men?
A)900micro gram #The RDA for vitamin A is 900 μg Retinol Activity Equivalents (RAE) per day for adult men and 700 μg RAE per day for adult women.2 At this intake, adequate body stores of vitamin A are maintained in healthy adults.
vitamin A,D,E and K are considered to be_______________ vitamins.
fat soluble
vitamin A is important in maintaining normal differentiation in cells related to the structural component of the eyes?
A) cornea: lens b) the retina: cones #Gene expression directs cell differentiation—the process in which stem cells develop into specialized cells with unique functions in the body. Vitamin A is especially important in maintaining normal differentiation of the cells that make up the structural components of the eye, such as the cornea (clear lens) and the retina (rod and cone cells).
RISK FACTORS ASSOCIATED WITH OSTEOMALICIA INCLUDE________.
A)KIDNEY DISEASE B)POOR INTESTINAL ABSORPTION #Vitamin D deficiency in adults is called osteomalacia, which means "soft bones." It is characterized by poor calcification of newly synthesized bone, resulting in fractures in the hip, spine, and other bones. (Do not confuse this disease with osteoporosis, discussed in calcium section.) Osteomalacia is most likely to occur in adults with kidney or liver disease (both of which impair the synthesis of calcitriol) or intestinal diseases that impair fat absorption (such as Crohn disease).3 Other adults at risk of deficiency include those with dark skin and with limited UV exposure.
some vitamins A is stored in which part of the body to maintain vitamin A pools?
A)eyes #Not all retinal is used in each cycle. Some is stored in the eye to maintain vitamin A pools. If vitamin A pools become depleted, the process of dark adaptation is impaired, making it difficult to adjust to seeing in dim light, known as night blindness. You may have had a brief experience similar to night blindness when you walked into a dark movie theater or when a bright light was suddenly shined in your eyes. However, this brief difficulty in seeing is not related to vitamin A deficiency because your vision quickly returns once your eyes have adjusted to the change in light.
sources of retinoid, the preformed source of vitamins A, include
A)fish B) liver C)fortified milk d)fortified margarine #Retinoids (preformed vitamin A) are found in liver, fish, fish oils, fortified milk, and eggs. Margarine is fortified with vitamin A, as are fat-free, low-fat, and reduced-fat milks.
________occurs when vitamin A deficiency progresses and leads to dryness of the cornea and eye membranes.
A)xerophthalmia #xerophthalmia—causes irreversible blindness in millions of people worldwide.
which of the following are the three types of vitamins
a) Retinol B)Retenoic acid c)Retinal in addition there is retinyl ester #Retinoids is a collective term for the biologically active forms of vitamin A. They are called preformed vitamin A because, unlike carotenoids, they do not need to be converted in the body to become biologically active. Retinoids exist in 3 forms: retinol (an alcohol), retinal (an aldehyde), and retinoic acid. The tail segment of the vitamin A structure terminates in 1 of these 3 chemical groups (alcohol, aldehyde, or acid) and determines the name or classification.
the damage caused by free radicals can be decreased by the presence of _____________
a) antioxidants #Antioxidants function in a variety of ways to regulate free radicals and prevent the damage they cause.
a vita min can be described as a(n)__________when it is thought to be responsible for reducing the risk of cancer by destroying free radicals.
a) antoxidant #Vitamin E is an important part of the body's antioxidant network, which helps maintain the integrity of cell membranes by stopping chain reactions caused by free radicals. Free radicals are very unstable compounds that have 1 or more unpaired electrons. Normally, atoms left with an unpaired electron after oxidation reactions immediately pair with each another, creating more stable compounds.
where are fat-soluble vitamins stored in the body?
a) liver #Because of the limited storage of many vitamins, they should be consumed daily. However, the signs and symptoms of a deficiency usually do not occur until the vitamin is lacking in the diet for at least several weeks and body stores are essentially depleted. Thus, an occasional lapse in dietary intake of most vitamins is not a serious health concern in otherwise healthy individuals
impaired kidney function can have an impact on these presence of adequate levels of which vitamins stored in the body?
a) vitamin D #Many older adults who live in northern climates or reside in nursing homes also are at increased risk of vitamin D deficiency. Not only do many of these individuals have little sun exposure, but they also may have reduced vitamin D levels from low dietary intakes and/or impaired kidney function, which limits conversion to the active form of vitamin D.20
the RDA for vitamin E is ________mg/ day
a)15mg/day #The RDA for vitamin E is 15 mg/day of alpha-tocopherol for both men and women.
what is the adequate intake level of vitamin k of women?
a)90micro grams/day #For women, the Adequate Intake for vitamin K is 90 μg/day; for men, it is 120 μg/day.
found in animal products found in plant products
a)Ratenoid b)cartanoid
the water soluble vitamins
a)Vitamins B and C #. Vitamins A, D, E, and K dissolve in organic solvents, such as ether and benzene, and are referred to as fat-soluble vitamins. The B-vitamins and vitamin C, in contrast, dissolve in water and are classified as water-soluble vitamins.
vitamin A analogs have been used in topical and oral medications to treat___________ and psoriasis.
a)acne #Several synthetic compounds with a chemical makeup similar to that of vitamin A (called analogs) have been used in topical and oral medications (e.g., Retin-A® and Accutane®) to treat acne and psoriasis
A vitamin deficiency may occur when a vitamin has been lacking in the diet for several weeks and the_______.
a)body stores are depleted. #. Because of the limited storage of many vitamins, they should be consumed daily. However, the signs and symptoms of a deficiency usually do not occur until the vitamin is lacking in the diet for at least several weeks and body stores are essentially depleted. Thus, an occasional lapse in dietary intake of most vitamins is not a serious health concern in otherwise healthy individuals.
when vitamin deficiency is present, the individuals with deficiency may experience ____ in health
a)decline #In fact, when vitamin intake is insufficient to meet needs, a deficiency develops, accompanied by a measurable decline in health. If the deficiency is not in advanced stages, the deficiency and related symptoms can be alleviated by increased intakes of the vitamin.
vitamin A is involved in the development of the?
a)eyes B)cardiovascular system c)limbs #Retinoids play an important role in embryonic development. From studies of animals, scientists learned that vitamin A is involved in the development of the eyes, limbs, cardiovascular system, and nervous system. They also noted that a lack of vitamin A during early stages of pregnancy resulted in birth defects and fetal mortality (death).
fat-soluble diets are absorbed along with dietary_________.
a)fat #Fat-soluble vitamins are absorbed along with dietary fat. Thus, adequate absorption of fat-soluble vitamins depends on efficient use of bile and pancreatic lipase in the small intestine to digest dietary fat and adequate intestinal absorption (Fig. 12-1).
the body is able to readily store which group of vitamins?
a)fat-soluble vitamins #What remains—the remnant—is taken up by the liver. This remnant contains the fat-soluble vitamins absorbed from the diet. The liver then "repackages" fat-soluble vitamins with new proteins for transport in the blood, or it stores them in adipose tissue or the liver for future use. In contrast to the fat-soluble vitamins, water-soluble vitamins are delivered directly to the bloodstream and distributed throughout the body.
for most vitamins, the natural forms(isolated from foods)_______.
a)have the same benefits as a synthetic forms(made in labratory) #Whether vitamins in supplements are isolated from foods or synthesized in a laboratory, these vitamins are usually similar chemical compounds and generally work equally well in the body. Contrary to claims in the health food literature, "natural" vitamin supplements isolated from foods are, for the most part, no more healthful than those synthesized in a laboratory.
which of the following are substances that glutathione peroxidase breaks down?
a)hydrogen peroxides b)lipid peroxides #Glutathione peroxidase, an enzyme in the cytoplasm and mitochondria of cells, is important in catalyzing the breakdown of hydrogen peroxides and lipid peroxides. These compounds are reactive oxygen species that can form free radicals if they combine with other compounds. Thus, by eliminating these peroxides, glutathione peroxidase helps vitamin E reduce oxidative damage to cells.
how might a person who consumes a diet adequate in fat still develop a fat soluble vitamin dificiency?
a)inseficient fat digestion and absorption #vitamins consumed in food must be absorbed efficiently from the small intestine to meet body needs. If the absorption of a vitamin is decreased, a person must consume larger amounts of it to avoid deficiency symptoms. For example, fat malabsorption (resulting from GI tract and pancreatic disease) may cause poor absorption of fat-soluble vitamins.1,2,3 Alcohol abuse and certain intestinal diseases also can lead to malabsorption of some B-vitamins (see Chapter 13). Individuals with these diseases usually require vitamin supplements to prevent deficiencies.
risk factors associated with osteomalacia include
a)kidney disease b)poor intestinal absorption #Vitamin D deficiency in adults is called osteomalacia, which means "soft bones." It is characterized by poor calcification of newly synthesized bone, resulting in fractures in the hip, spine, and other bones. (Do not confuse this disease with osteoporosis, discussed in calcium section.) Osteomalacia is most likely to occur in adults with kidney or liver disease (both of which impair the synthesis of calcitriol) or intestinal diseases that impair fat absorption (such as Crohn disease).3 Other adults at risk of deficiency include those with dark skin and with limited UV exposure.20,23,24 Page 425Many older adults who live in northern climates or reside in nursing homes also are at increased risk of vitamin D deficiency. Not only do many of these individuals have little sun exposure, but they also may have reduced vitamin D levels from low dietary intakes and/or impaired kidney function, which limits conversion to the active form of vitamin D.20
where are the fat soluble vitamins stored in the body.
a)liver #With the exception of vitamin K, fat-soluble vitamins are not readily excreted from the body. Instead, they are often stored in the liver and/or adipose tissue.
whne megadose of vitamin is given to someone, the person is recieving______.
a)much more than needed #In addition to preventing deficiency diseases, a few vitamins have been useful as pharmacological agents (drugs) in treating several nondeficiency conditions. These treatments often require the administration of megadoses, amounts much higher than typical human needs for the vitamin. For example, megadoses of a form of niacin can be used as part of blood cholesterol-lowering treatment for certain individuals.
vitamin D deficiency in adults is called__________.
a)osteomalacia #Vitamin D deficiency in adults is called osteomalacia, which means "soft bones." It is characterized by poor calcification of newly synthesized bone, resulting in fractures in the hip, spine, and other bones. (Do not confuse this disease with osteoporosis, discussed in calcium section.) Osteomalacia is most likely to occur in adults with kidney or liver disease (both of which impair the synthesis of calcitriol) or intestinal diseases that impair fat absorption (such as Crohn disease).3 Other adults at risk of deficiency include those with dark skin and with limited UV exposure.20,23,24
which three of the following groups are at risk of a vitamins E deficiency
a)preterm infants b)individuals with crohn disease c)smokers #Overt vitamin E deficiency is rare in humans. Individuals at greatest risk of deficiency are those with fat malabsorption conditions, such as cystic fibrosis or Crohn disease, smokers, and preterm infants.
over time vitamin E is ______ in humans.
a)rare ##Overt vitamin E deficiency is rare in humans. Individuals at greatest risk of deficiency are those with fat malabsorption conditions, such as cystic fibrosis or Crohn disease, smokers, and preterm infants.
which of the following are possible for vitamin D dificiency has remeerged as a global health concern?
a)the use of screen b)clothing that fully covers the body c)spending time indoors #The fortification of milk with vitamin D and the prophylactic use of cod liver oil almost completely eradicated the epidemic of rickets in the 19th century. However, vitamin D deficiency has reemerged as a global health concern. Some experts feel that low intakes of vitamin D, coupled with behaviors that limit UV-light exposure (e.g., time spent indoors, the use of sunscreen, the use of clothing to fully cover the skin), have resulted in widespread inadequate vitamin D status.
infants are given an injection of vitain K at birth because______
a)they intestines lack the neccesary bacteria to produce vitamin K. #Vitamin K deficiency can occur in newborns because vitamin K stores are typically low at birth and the intestinal tracts of newborns do not yet have bacteria that can synthesize vitamin K. This increases the risk of bleeding due to defective blood clotting; thus, newborn infants in North America are given vitamin K injections within 6 hours of delivery.
a ____is AN ORGANIC COMPOUND needed in small amounts in the diet to help regulate an support chemical reactions in the body
a)vitamin #Vitamins are essential, organic (containing carbon bonded to hydrogen) substances needed in small amounts in the diet. They are not a source of energy. Instead, they aid in energy metabolism as well as in the growth, development, and maintenance of body tissues.
which fat-soluble vitamins are most often associated with toxicity?
a)vitamin A b)vitamin D
excessive intakes of vitamin A and vitamin _____ negatively effect the action of vitamin K.
a)vitamin E #Excessive intakes of vitamin A and vitamin E negatively affect the actions of vitamin K.
which vitamin is given as injection to infants at birth due to the inability of the bacteria in the intestines to produce enough.
a)vitamin K ##Vitamin K deficiency can occur in newborns because vitamin K stores are typically low at birth and the intestinal tracts of newborns do not yet have bacteria that can synthesize vitamin K. This increases the risk of bleeding due to defective blood clotting; thus, newborn infants in North America are given vitamin K injections within 6 hours of delivery.