Fundamentals of Nursing Q 36
An additional Vitamin C is required during all of the following periods except:
A. Infancy
B. Young adulthood
C. Childhood
D. Pregnancy
Correct Answer: B. Young adulthood
Additional Vitamin C is needed in growth periods, such as infancy and childhood, and during pregnancy to supply demands for fetal growth and maternal tissues. Other conditions requiring extra vitamin C include wound healing, fever, infection and stress. Vitamin C is a water-soluble vitamin, antioxidant, and essential cofactor for collagen biosynthesis, carnitine and catecholamine metabolism, and dietary iron absorption. Humans are unable to synthesize vitamin C, so they can only obtain it through dietary intake of fruits and vegetables.
Option A: An infant requires Vitamin C. Although most vitamin C is completely absorbed in the small intestine, the percentage of absorbed vitamin C decreases as intraluminal concentrations increase. Proline residues on procollagen require vitamin C for the hydroxylation, making it necessary for the triple-helix formation of mature collagen. The lack of a stable triple-helical structure compromises the integrity of the skin, mucous membranes, blood vessels, and bone.
Option C: Children need lots of Vitamin C. Usual dietary doses of up to 100 mg/day are almost completely absorbed. The highest concentrations of ascorbic acid are in the pituitary gland, the adrenal gland, the brain, leukocytes, and eyes. Ascorbic acid functions as a cofactor, enzyme complement, co-substrate, and a powerful antioxidant in a variety of reactions and metabolic processes. It also stabilizes vitamin E and folic acid and enhances iron absorption. It neutralizes free radicals and toxins as well as attenuates inflammatory response, including sepsis syndrome.
Option D: A pregnant woman requires an abundant amount of Vitamin C. The average protective adult dose of vitamin C is 70 to 150 mg daily. Increase the dose to 300 mg to 1 g daily when scurvy is present. Daily need increases in patients with conditions like gingivitis, asthma, glaucoma, collagen disorders, heatstroke, arthritis, infections (pneumonia, sinusitis, rheumatic fever), and chronic illnesses. Hemovascular disorders, burns, and delayed wound healing are causes for an increase in daily intake.