Vitamins and Trace Elements

Question 1

Name the fat-soluble and water-soluble vitamins

Answer 1

Fat-soluble: vitamins A, D, E, and K
Water-soluble: all B vitamins, C, and choline

Question 2

3 forms of Vitamin A?

Answer 2

Retinol, retinaldehyde (retinal), and retinoic acid

Question 3

Typical form that vitamin A is ingested as?

Answer 3

Retinyl ester

Question 4

Primary storage sites of vitamin A

Answer 4

Liver is primary site. Also stored in adipose tissue, kidneys, bone marrow, lungs, eyes

Question 5

Role of vitamin A in wound healing?

Answer 5

As retinoic acid, it is needed for epithelial cell growth. Vitamin A increases the number of macrophages and monocytes in the wound during the inflammatory phase, stimulates epithelialization, increases collagen deposition by fibroblasts. Can also reverse the inhibitory effects of corticosteroids on wound healing

Question 6

1 mcg of retinol is equivalent to the activity of __ mcg beta-carotene from food?

Answer 6

1 mcg retinol = 12 mcg beta-carotene

Question 7

RAE (retinoic acid equivalent) is equal to what amount of each of the following: retinol, IU retinol, mcg food-based beta-carotene, mcg alpha-carotene, mcg beta-cryptoxanthin

Answer 7

1 mcg retinol
3.33 IU retinol
12 mcg food-based beta-carotene
24 mcg alpha-carotene
24 mcg beta-cryptoxanthin

Question 8

How does vitamin D absorption occur?

Answer 8

In tandem with fat and bile salts via passive diffusion into the intestinal cell where it is packaged as chylomicrons for entrance into the lymphatic system and then into the blood

Question 9

What is the first B vitamin deficiency that usually manifests in alcoholism?

Answer 9

Thiamine

Question 10

What considerations should be made when a patient on warfarin therapy is receiving PN?
Scenario: 52 y/o M w/ stage IV colon cancer s/p chemo presents w/ severe nausea, vomiting, abd pain, and distention, last BM 5 days ago with no intake other than sips of fluids. Pt is found on CT to have an ileus and also DVT of LLE. NG placed to suction. Unable to tolerate oral feedings after 48 hours of admission so PN is started. Advanced to liquid diet and transitioned to warfarin therapy with a target INR of 2-3. During warfarin therapy INR remains subtherapeutic despite frequent increases in warfarin dose until it reaches abnormally high levels

Answer 10

Nutrition support clinician should assess the vitamin K intake from PN sources and its impact on warfarin dosage. PN is adjusted to decrease vitamin K to achieve therapeutic INR at a stable warfarin dose. If possible, switch patient to a multivitamin product that does not contain vitamin K, such as MVI-12 (Hospira). If lipid emulsion also provides a high dose of vitamin K, it may also be adjusted

Question 11

Vitamin K content of parenteral multivitamin Infuvite? Range of vitamin K content in lipid emulsions depending on the fat source?

Answer 11

150 mcg vitamin K per unit dose (10 mL)
0-1000 mcg vitamin K per liter in lipid emulsions

Question 12

What is an extra challenge with the provision of nutrition support to patients receiving warfarin therapy?

Answer 12

The variable vitamin K content in lipid emulsions along with the periodic nature of their administration (lipids given 3 times/week rather than daily)

Question 13

Describe the vitamin K content of Propofol?

Answer 13

Propofol is 10% soybean oil. Soybean oil has approximately 1.7 mcg vitamin K per mL

Question 14

How does thiamin deficiency affect nutrient metabolism?

Answer 14

Thiamin is necessary for the conversion of pyruvate to acetyl-CoA, a major step in the transformation of glucose to adenosine triphosphate. In the absence of thiamin, energy metabolism is impaired. As pyruvate builds up, it is driven toward lactic acid fermentation, which causes the spike in lactate and contributes to metabolic acidosis. Thiamin is necessary for the Krebs cycle enzyme alpha-ketoglutarate dehydrogenase. Together, these conditions decrease the acetyl-CoA entering the Krebs cycle from carb metabolism and limit the energy substrates produced in the Krebs cycle from fatty acid-derived acetyl-CoA

Question 15

Patient scenario: Patient presents with SOB, restlessness, mild confusion. Also with severe edema in lower extremities and abdominal ascites 2/2 alcoholic liver cirrhosis. Oral intake has been inadequate for the past month due to binge drinking. Started on furosemide 40 mg. Day 2 restlessness progresses to combative behavior, increased confusion, nystagmus, leg tremor. ABG indicative of metabolic acidosis which is unresponsive to treatment. Serum Mg is 1.5, slightly below normal. What is the appropriate intervention?

Answer 15

Wernicke encephalopathy 2/2 thiamin deficiency is suspected. Furosemide is discontinued and replaced with oral spironolactone. Furosemide promotes urinary thiamin wasting. A multivitamin is administered along with thiamin (200mg 3x daily) for 5 days. Initial dose is given with- 1gm Mg sulfate. Confusion and agitation, as well as metabolic lactic acidosis, resolve within 6 hours of treatment. Patient sent home on oral thiamin supplement of 100mg 3x/day. Dose decreased to 100mg/day in 2 weeks

Question 16

Describe the mechanisms through which severe alcoholism causes thiamin deficiency

Answer 16

1. People with alcoholism often replace nutrient-dense energy sources with energy from alcohol intake, which can lead to malnutrition
2. Ethanol inhibits intestinal thiamin absorption
3. The active for of thiamin, thiamin pyrophosphate, is synthesized in the liver, making liver cirrhosis a possible contributing factor in thiamin deficiency

Question 17

Thiamin deficit occurs within how many days of inadequate intake?

Answer 17

14-20 days

Question 18

What nutrient is necessary for the conversion of thiamin to its active form, thiamin diphosphate?

Answer 18

Magnesium. A Mg deficiency effectively renders thiamin unusable

Question 19

What is the suggested thiamin replacement for suspected Wernicke encephalopathy or Wernicke-Korsakoff syndrome (from a recent compilation of evidence, however recommendations vary widely)?

Answer 19

For 3-5 days: 100-200 mg IV or intramuscular thiamin 3x/day before high carb meals
For the next 1-2 weeks: 100 mg oral thiamin 3x/day
Then 100 mg oral thiamin once daily thereafter

Question 20

What is the recommended treatment for confirmed Wernicke encephalopathy or Wernicke-Korsakoff syndrome?

Answer 20

200-500 mg IV or intramuscular thiamin 3x/day for 5-7 days
100 mg oral thiamin 3x/day for the next 1-2 weeks
Then 100 mg oral thiamin once daily thereafter

Question 21

Which essential amino acid can synthesize the coenzyme nicotinamide adenine dinucleotide (NAD)?

Answer 21

Tryptophan. 60 mg tryptophan produces 1 mg niacin

Question 22

Nutrients of concern when a tuberculosis patient is being treated with Isoniazid?

Answer 22

Niacin (B3), Vitamin B6 (pyridoxine)

Question 23

Besides inadequate iron intake, what other mineral deficiencies or excesses may create hematological indices consistent with iron deficiency anemia and why?

Answer 23

Copper deficiency interferes with iron absorption and thus effectively creates copper deficiency anemia (iron deficiency anemia in patients with iron replete status). Zinc toxicity creates a copper deficiency, initiating the same mechanisms. Chromium toxicity can contribute to iron deficiency anemia due to its receptor site competition with iron