0071483446.pdf

(^142) CHAPTER 9 Vitamins and Minerals
Dose for treatment Malabsorption: 30–100 mg/day
of deficiency Severe deficit: 1–2 mg/kg/d or 50–200 IU/kg/day
Maintenance Male: 10 mg/d; 15 IU
Female: 8 mg/d; 12 IU
Pregnancy: 10–12 mg/day
Pregnancy category A (C if used in doses above RDA)
Deficiency conditions Breakdown of red blood cells
Side effects None significant
Adverse reactions Large doses may cause fatigue, weakness, nausea, GI upset,
headache, breast tenderness, and may prolong the prothrombin
time (PT) (clotting time).
Contraindications Patients taking warfarin (anticoagulant) should have their PT
monitored closely. Iron and vitamin E should not be taken together
because iron can interfere with the body’s absorption and use of
vitamin E.
Vitamin E
regulating the metabolism of calcium and phosphorus. There are two forms of
Vitamin D: D 2 , called ergocalciferol; and D 3 , called cholecalciferol. D 2 is a
synthetic fortified form of Vitamin D. D 3 is the natural form of Vitamin D that
is produced in the skin by ultraviolet sunlight. Once absorbed, Vitamin D is
converted into calcifediol in the liver and then converted to an activated form of
calcifediol in the kidneys. The active form is a hormone that combines with
parathyroid hormone (PTH) and calcitonin to regulate calcium and phosphorus
metabolism in the body and stimulate the reabsorption of calcium and phospho-
rus by bone. When serum levels of calcium are low, more Vitamin D is used to
create the active form of calcifediol. Low serum levels of calcium cause a
decrease in the creation of the active form of calcifediol. Excess Vitamin D is
then excreted in bile and a small amount is excreted in urine.
Vitamin E
Vitamin E protects the heart and arteries and cellular components from being
oxidized and prevents red blood cells from hemolysis (rupture). If there is a
sufficient balance of salts, pancreatic secretion, and fat, Vitamin E is absorbed
from the GI tract and stored in all tissues, especially in the liver, muscle, and
fatty tissues. Seventy-five percent of excess Vitamin E is excreted in the bile
and the remainder is excreted in urine.