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
