Ch 8: Vitamins and Trace Minerals Flashcards
What foods interferes with iron absorption?
Phytic acid in grains, oxalic acid in spinach,chard, teas, and chocolate, polyphenols in coffee, tea, and cocoa.
What are the retinol acid equivalents?
1 mcg retinol, 3.33 IU retinol, 12 mcg food-based beta-carotene, 24 mcg alpha carotene or 24 mcg beta cryptoxanthin.
UL for retinol is 3000 RAE (3000 mcg).
What enhances absorption of Riboflavin? What inhibits it?
Presence of food enhances absorption; divalent metals, such as copper,zinc, iron, and manganese form chelates w/ riboflavin and prevent its absorption.
ETOH also impairs digestion/absorption of riboflavin.
Where are the sources of vitamin D?
Sunlight, fish liver oil,fatty fish, fortified milk, breakfast cereal
B12 often presents as which deficiency?
Folic acid; When B12 is lacking, folate becomes trapped inits methyl (inactive form). For this reason, B12 deficiency often presents as folate deficiency and is therefore commonly misdiagnosed.
More than 50% of home PN patients have exhibited what toxicity coupled with clinically significant cerebral and hepatic complications?
Manganese toxicity
Which vitamin is known as B6
Pyridoxine
When iodine is deficient, insufficient what is produced, thereby eliminating its negative feedback on thyroid stimulating hormone (TSH)?
T4
What is the classic niacin deficiency disease?
Pellagra; presents as the three “Ds”—dermatitis, diarrhea, and dementia
What are the signs of vit E deficiency?
Ceroid pigmentation (age spots), vision changes, ophthalmoplegia, ptosis, vision loss, dysarthria, ataxia, neuronal degeneration, hemolytic anemia, increased platelet aggregation, urinary creatinine wasting
What is used to express folate requirements to reflect differences in absorption of food vs synthetic folate and what are they?
Dietary Folate Equivalents; 1 mcg food folate, 0.6 mcg fortified/supplemental folic acid taken w/food, or 0.5 mcg supplemental folic acid taken without food
Which patients are at risk for Chromium deficiency?
Patients receiving PN without chromium supplementation are at risk for deficiency
Clinical signs of iron deficiency include?
pallor, koilonychia, conjunctival pallor, glossitis, impaired behavior and intellectual performance, microcytic, hypochromic anemia, tachycardia, poor capillary refilling, fatigue, sleepiness,headache, anorexia, nausea, reduced work performance, impaired ability to maintain body temp in cold environments, decreased resistance to infections,increased lead absorption, and adverse outcomes during pregnancy.
How does PTH increase blood calcium levels?
- PTH in the kidneys stimulates increased renal retention and conversion of calcidiol (inactive D) to active form, calcitriol
- Both calcitriol and PTH act on the bone,stimulating osteoclast activity for the resorption of ca into the bloodstream.
- Calcitriol travels to the intestines to increaseexogenous ca absorption.
- Once serum ca has normalized, PTH secretion decreases,halting the cycle
What levels are elevated in 90% of patients with a B12 deficiency?
Serum levels of methylmalonic acid (MMA) and homocysteine
In which situations should large doses of Vit C be avoided?
Renal failure, kidney stones (Pt’s prone to oxalate or uric acid-based stones should not exceed 500 mg/d) iron overload, and pt’s on heparin or warfarin therapy
What are symptoms of folate deficiency?
Cheilosis, nervous instability, dementia, megalobastic or macrocytic anemia
What does NADH help activate?
Folate
Where if vitamin K synthesized?
Vit K is synthesized by gut microflora in the distal small intestine and colon (forms are phylloquinones, menaquinones, and menadione)
What are the forms of Vitamin D, and where are they found?
Vitamin D: refers to both ergocalciferol (D2) and cholecalciferol (D3) which are either consumed in the diet or synthesized in the skin from a compound to solar or artificial UV light
In which cases should vitamin A be supplemented with caution?
Renal failure (acute or chronic)
What can clinical situations/diagnoses impair vitamin B12 absorption?
pancreatic insufficiency, impaired HCL (older adults), patients with H Pylori infections, those taking H2 antagonist, and patients who have had portion or all of the ileum/stomach removed, chronic malabsorption
Which vitamins are considered essential?
The 8 “B vitamins” (thiamine, niacin, riboflavin, folate, B6, B12, Biotin, and Pantothenic acid)
Vitamin C, Vitamins A, D, E, K and Choline are also considered essential
What is affected by toxic amounts of Vitamin A?
The skeletal system
Which essential AA can Niacin be synthesized from?
Tryptophan; 60mg tryptophan = 1 mg niacin
Which conditions are linked to an increased urinary excretion of chromium?
DM2 and pregnancy
Besides diet, where are other sources of vit K?
Propofol and ILE.
Many additives to PN may also include vit K
Intake of more than ____mg of vitamin E per day interferes with vitamin K and may be problematic for patients receiving warfarin therapy
1200 mg/day
What are the food sources of Vitamin A?
liver, fortified milk, eggs, and dark green/yellow/orange vegetables
What foods, beverages, and supplements inhibit Zinc absorption?
Calcium supplements
Inhibitors of zinc absorption also includes other minerals, vitamins, proteins, phytic acid, and ETOH.
Certain milk proteins may have a negative effect on absorption as well.
What are signs of selenium deficiency?
Selenium deficiency signs: increased susceptibility to mercury expose, altered thyroid metabolism, congestive cardiomyopathy secondary to Keshan disease, nausea, vomiting
What is the role of Niacin in the body?
The nicotinamide portion of NAD and NADP serveas hydrogen donor or an electron acceptor for more than 200 enzymes involved in intermediary metabolism.
Niacin also helps regulate the body’s antioxidant system
What is the recommendation for zinc in wound healing?
Up to 40 mg zinc (176 mg zinc sulfate) for 10 days.
What are the classic thiamin deficiency diseases?
Beri beri and Wernicke encephalopathy.
Wernicke encephalopathy can develop into Wernicke-Korsakoff syndrome
Which populations are at risk for vit K deficiency?
Fat malabsorption, IBD, antibiotic therapy, long term PN w/o lipid emulsion, NPO status (there is no storage mechanism for vit K in the body)
Zinc affects the metabolism of which vitamin?
Vitamin A–zinc affects vitamin A metabolism by decreasing retinol mobilization from the liver and decreasing zinc dependent enzyme conversion of retinol to retinal, which is critical to the vision cycle
What competes with chromium supplementation?
Iron, b/c chromium and iron compete for binding sites on transferrin.
Administration of warfarin w/ continuous enteral nutrition leads to ______ warfarin absorption
Decreased
What are some signs of copper deficiency?
Hair/skin hypo-pigmentation, Kayser Fleischer rings, sensory ataxia, LE spasticity, paresthesia in extremities, myeloneuropathy, hypochromic microcytic anemia, leukopenia, abnormal EKG patterns
Which populations are at risk for vitamin A deficiency?
Patients with fat malabsorptive disorders and pregnant women
What are the functions of Vitamin A?
Vision, epithelial cell regulations, bone/cellular health, and wound healing
Which populations are most at risk for a vitamin D deficiency?
Older adults, NH residents, dark skinned individuals, people who wear clothes or veils that expose little skin, people who are indoors much of the time, use sun screen daily, and exclusively breastfed infants.
Pts with extensive skin damage, fat malabsorptive disorder, or renal disease (insufficient renal calcitriol production) and those on long term PN are also at risk
What are some signs of a molybdenum deficiency?
Dislocation of ocular lens, altered vision, AMS, attenuated brain growth, neurologic damage, tachycardia, tachypnea, elevated methionine, headache, lethargy, N/V·
What is secreted with blood calcium levels are low?
PTH
Iodine functions as an integral component of which hormones?
Iodine functions as an integral component of thyroid hormones thyroxine (T4) and triiodothyronine (T3).
How quickly can thiamin deficiency occur?
14-20 days
High levels of zinc (greater than 40 mg/d) may cause which deficiency?
Copper
Which patients are at risk for copper deficiency?
Malabsorptive disorders such as celiac, patient recovering from under nutrition associated w/ chronic diarrhea, those recovering from intestinal surgery, those receiving HD where copper losses can be excessive.
Individuals who have had bariatric surgery may also be at increased risk of deficiency.
What supplments/minerals interfere with iron absorption?
Calcium, zinc, and manganese (form insoluble iron complexes therefore reducing iron absorption)
Besides food, where can Biotin (B7) be found?
Colonic microflora
What is the AI for vit K?
AI for vitamin K is 120 mcg (men) and 90 mcg (women). No UL has been established.
Which patients are at risk for developing a manganese toxicity?
Populations at risk for developing toxicity include those receiving long term PN (> 30 days)
Also, patients who develop obstruction of the biliary tract and are unable to excrete manganese and are at risk for toxicity
Who is at risk for Thiamin deficiency?
Pt’s with vomiting or alcoholism, gastric surgery, and long term PN or dialysis, patients w/ refeeding syndrome, pt’s who receive insufficient thiamin supplementation during shortages of injectable MVI
Which patients are at risk for a folate deficiency?
Pt’s with a zinc deficiency and alcoholics. Pregnancy, and pt’s taken phenytoin, cholestyramine, or sulfasalazine. Drugs that change the luminal jejunal pH can also limit folate absorption. Conditions/diseases that impair bile secretion may also limit folate absorption
When is prophylactic copper supplementation recommended?
For patients with celiac disease when anemia or neutropenia is present
What are the signs of a vit K deficiency?
Bruising, prolonged bleeding, decreased bone density, and increased prothrombin time
What are some signs/symptoms of B12 deficiency?
Bone marrow changes, bone fractures, glossitis, paresthesia, unsteadiness, cognitive decline, confusion, depression, mental slowness, poor memory, delusions, psychosis, megablastic anemia, leukopenia, thrombocytopenia, CVD, neutrophil nuclei hyper segmentation
Niacin is also known as which vitamin?
Vitamin B3
Untreated thiamin deficiency can lead to what?
Fatal lactic acidosis
Vit B12 is needed for the conversion of what to which benign amino acid?
Vi tB12 is needed for the conversion of homocysteine to the benign AA methionine.
Who is most at risk for a Niacin deficiency?
Those with malabsorptive disorders, alcoholics, older adults ,and patients on anti TB med isoniazid or CA/autoimmune therapy mercaptopurine
Who is most at risk for Biotin deficiency?
Patients on long term PN, alcoholics,and patients with partial gastrectomy
What is the recommended treatment for iron deficiency?
150-200 mg elemental iron per day.
Common preparations include ferrous sulfate, gluconate, and fumarate.
What are the principal functions of vitamin D?
To support neuromuscular function, bone calcification, and other cellular processes.
Calcitriol also functions to maintain circulating serum levels of Ca and phos WNL
Where is most of the body’s zinc content contained?
Intracellulary
What is the primary function of vitamin E?
Maintenance of membrane integrity in body cells via its action as an antioxidant
Who is at risk for iron deficiency?
Women of childbearing age, patients
Who undergo excess blood sampling, those with decreased gastric acid production, Andre concomitant use of meds that reduce stomach acidity (antacids,H2 antagonists, PPIs).
Also, those with malabsorptive disorders, GBP patients/other GI surgeries, and patients after injury or inflammation are at risk for iron deficiency
What are signs of vitamin D toxicity?
Calcification of soft tissues (CVD, lungs), confusion, psychosis, tremor, hypercalcemia, hypoercalciuria
Which patients are most at risk for fat soluble vitamin deficiencies?
Patients with fat malabsorptive disorders or decreased intestinal surface.
How is megaloblastic anemia recognizable?
Megaloblastic anemia is recognizable as MCV > 100 fL/cell.
What is the primary function of vitamin C?
Antioxidant; also enhances intestinal absorption of non heme iron
Iron deficiency anemia usually presents as what?
Microcytic and hypochromic
What is the function of Chromium?
Chromium is an essential trace metal required for glucose and lipid metabolism
What should always be determined with folate status?
B12 status and homocysteine concentrations should also be determined in tandem with folate status.
What is the recommended thiamin intake for adults?
Men 1 .2 mg, women 1.1 mg
What is the active form of Vitamin D?
Calcitriol
Unlike other vitamins, where can B12 be stored?
Liver
When should copper be administered with caution?
In patients hepatic dysfunction, as it is excreted in the liver
What are the signs of iodine deficiency?
Elevated TSH, Jod-basedow phenomenon, nodular goiter, weight loss, tachycardia, muscle weakness, skin warmth.
High levels of what supplments compete with zinc absorption?
Calcium and iron
____ a liver synthesized protein that is required to transport retinol form the liver to the target tissues.
Retinol Binding Protein
What is the role of Riboflavin (Vit B2) in the body?
Precursor to FMN and FAD, which are involved in a wide variety of enzymatic reactions in intermediary metabolism
What is the role of Choline in the body?
Cell membrane signaling, neurotransmitter synthesis, and lipid transport
What are signs of vitamin D deficiency?
Osteomalacia, tetany, hypocalcemia
What are some clinical manifestations of vitamin A deficiency?
Follicular hyperkeratosis, bigot’s spots, xeropthalmia, night blindness, excessive bone deposition, impaired wound healing
The best understood biochemical function of selenium is as a required cofactor in what?
A required cofactor in glutathione, iodine, and thyroid metabolism
What is the RDA for vitamin C?
Men: 90 mg
Women: 75 mg
What mineral is a necessary co-factor in the conversion of thiamine to its active form in the liver
Magnesium
Warfarin ____INR, whereas vit K _____ it.
Increases; decreases
When is parenteral use of iron not recommended?
During acute illness or sepsis
A parenteral administration of iron may contribute to oxidative reactions that exacerbate tissue damage.
In addition, excessive amounts of circulating iron may stimulate bacterial proliferation
Zinc binds to what for transport into the liver?
Zinc binds to albumin for transport to the liver.
What is the short term form of iron storage?
Ferritin
Which populations at risk for vit E deficiency?
Those with fat malabsorptive disorders, Crohn’s disease, CF, compromised biliary function, or resection of ileum/small intestine.
Long term PN patients also at risk.
Where is iron primarily absorbed?
Iron is absorbed primarily in the duodenum and jejunum
The clinical manifestations of copper deficiency can be similar to what other micronutrient deficiency?
B12
Which of the following is the best way to determine chromium deficiency?
There is no known reliable indicator of chromium status
What are some symptoms of a Zinc deficiency?
Symptoms can be reported as loss of taste sensation, altered smell sensation, and skin rash in severe cases. Decreased vitamin A release from the liver can contribute to nighttime blindness.
How often should micronutrient assessments be performed on long-term parenteral nutrition (PN) patients?
Every 6 months
Every patient should receive micronutrients daily unless there is a potential or identified nutrient toxicity, or adjust accordingly if there is a national shortage of product. Whenever a nutrient is omitted or added to standard micronutrient recommendations, the patient should be monitored for a potential deficiency or toxicity that could develop over time. Laboratory values are not always reliable indicators
Cheilosis, cracking of the corners of the mouth, is observed with a deficiency of which vitamins/minerals?
riboflavin, niacin, iron, and pyridoxine.
What vitamin absorption is most likely to be impaired with chronic use of proton pump inhibitor therapy?
B12
Which vitamin/mineral deficiencies result in microcytic, hypochromic anemia?
Copper and iron
Which vitamin/mineral deficiencies result in macrocytic anemia?
B12 or Folate
When supplemented, which vitamins may reduce plasma homocysteine concentrations?
Folic acid, vitamin B6, and vitamin B12 supplementation can reduce plasma homocysteine concentrations
What is the recommended amount of Vitamin A supplementation to be given to a patient with suspected vitamin A deficiency on steriod therapy?
A wide dosage range of 3000 to 15,000 RAE/d orally for 7 days has been recommended to counteract the inhibitory effects that steroids have on collagen synthesis and connective tissue repair.
True or false: PN associated metabolic bone disease It is often asymptomatic and occurs in the face of normal biochemical parameters.
True
