VITAMINS AND MINERALS Flashcards
What are vitamins and why are they required in the human diet?
Vitamins are required constituents of the diet as they are synthesized inadequately or not at all in the human body. Only small amounts are needed to carry out essential biochemical reactions.
What factors make vitamin deficiencies less common in Western countries?
Plentiful, varied, and inexpensive food supply; food fortification; and use of supplements.
Who is at higher risk for multiple nutrient deficiencies?
Chronically ill or alcoholic individuals.
Where are vitamins B12 and A stored, and how long until deficiency symptoms appear?
Vitamins B12 and A are largely stored in the liver. Symptoms may not appear until a year of poor intake.
How quickly can folate and thiamine become depleted in a deficient diet?
Within weeks.
How do hemodialysis and diuretics affect vitamin levels?
Hemodialysis depletes essential nutrients, and diuretics deplete water-soluble vitamins.
How can disease states like malabsorption affect vitamins and minerals?
They can cause deficiencies of vitamins and minerals.
What is an example of vitamin toxicity causing disease?
Vitamin A intoxication leading to liver disease.
What is a therapeutic use of vitamins in high doses?
Niacin combined with a statin for hypercholesterolemia.
What are the primary functions of thiamine?
Energy generation, transketolase reactions, and peripheral nerve conduction.
What are the main food sources of thiamine?
Yeast, organ meat, pork, legumes, beef, whole grains, and nuts.
What destroys thiamine content in food?
Tea, coffee, raw fish, and shellfish contain thiaminases that destroy thiamine.
What populations are at risk for thiamine deficiency?
Alcoholics, patients with chronic diseases (e.g., cancer), those with hyperemesis gravidarum, bariatric surgery patients, and those on chronic diuretic therapy.
What are the early signs of thiamine deficiency?
Anorexia, irritability, and decreased short-term memory.
What are the two types of beriberi and their primary symptoms?
Wet beriberi: cardiovascular symptoms like enlarged heart, tachycardia, CHF. Dry beriberi: symmetric peripheral neuropathy affecting motor and sensory systems, especially in the legs.
What are the key features of Wernicke’s encephalopathy?
Horizontal nystagmus, ophthalmoplegia, cerebellar ataxia, and mental impairment.
What is Wernicke-Korsakoff syndrome?
A condition with additional memory loss and confabulatory psychosis, often underdiagnosed.
How is thiamine deficiency diagnosed in the lab?
Enzymatic assay of transketolase activity before and after adding thiamine pyrophosphate. >25% stimulation indicates deficiency.
What is the treatment for acute thiamine deficiency?
200 mg thiamine IV three times daily until symptoms improve, then oral thiamine (10 mg/d) until recovery.
What improvements can be seen within 24 hours of thiamine treatment?
Cardiovascular and ophthalmoplegic improvements.
What side effects or toxicity are associated with thiamine?
Anaphylaxis after high intravenous doses. No adverse effects from food or oral supplementation.
What are the main functions of Vitamin B2 (Riboflavin)?
Metabolism of fat, carbohydrate, and protein; respiratory coenzyme and electron donor; cofactor for methyltetrahydrofolate reductase; involved in drug and steroid metabolism and detoxification reactions.
What are the symptoms of Vitamin B2 deficiency?
Mucocutaneous lesions; nonspecific symptoms such as lesions on the mouth and skin, corneal vascularization, anemia, personality changes.
Which foods are rich in Vitamin B2?
Milk, dairy products, lean meat, fish, eggs, broccoli, legumes, and enriched breads and cereals.
How is Vitamin B2 deficiency diagnosed?
By measuring red blood cell or urinary riboflavin concentration and erythrocyte glutathione reductase activity with and without added FAD.
What are the main functions of Vitamin B3 (Niacin)?
Involved in oxidation and reduction reactions, DNA repair, calcium mobilization, and metabolism of nutrients.
What foods are rich in Vitamin B3?
Beans, milk, meat, eggs, enriched flour.
What are the main symptoms of Pellagra (Vitamin B3 deficiency)?
Loss of appetite, weakness, irritability, abdominal pain, vomiting, bright red glossitis, Casal’s necklace, diarrhea, depression, seizures, dementia.
What are the ‘Four D’s’ of Pellagra?
Dermatitis, Diarrhea, Dementia, Death.
What is the treatment for Pellagra?
100-200 mg of nicotinamide or nicotinic acid PO three times daily for 5 days.
What are the toxicity symptoms of Vitamin B3?
Flushing, nausea, vomiting, abdominal pain, hepatic toxicity, glucose intolerance, hyperuricemia, and rhabdomyolysis.
What is the primary function of Vitamin B5 (Pantothenic Acid)?
Component of coenzyme A and involved in fatty acid metabolism, cholesterol synthesis, and protein acetylation.
What are the symptoms of Vitamin B5 deficiency?
Burning feet syndrome, gastrointestinal disturbance, depression, muscle cramps, paresthesia, ataxia, and hypoglycemia.
What foods are rich in Vitamin B5?
Liver, yeast, egg yolks, whole grains, and vegetables.
What are the main functions of Vitamin B6 (Pyridoxine)?
Cofactor for over 100 enzymes involved in amino acid metabolism, heme synthesis, neurotransmitter synthesis, and conversion of tryptophan to niacin.
What are the symptoms of Vitamin B6 deficiency?
Peripheral neuropathy, abnormal EEG, depression, confusion, microcytic hypochromic anemia, platelet dysfunction, hyperhomocysteinemia.
Which foods are rich in Vitamin B6?
Legumes, nuts, wheat bran, meat, animal tissues, and plant-based pyridoxine sources.
What is the upper limit for Vitamin B6 intake, and what happens with toxicity?
100 mg/day; severe sensory neuropathy, photosensitivity, dermatitis.
What is the primary source of Vitamin B12 (Cobalamin)?
Animal-based foods like meat, fish, and dairy products.
What are common causes of Vitamin B12 deficiency?
Inadequate dietary intake, gastric causes (e.g., pernicious anemia), intestinal causes (e.g., malabsorption, fish tapeworm), and prolonged deficiency leading to megaloblastic anemia.
What are the diagnostic features of Vitamin B12 deficiency in a complete blood count?
Oval macrocytes, anisocytosis, poikilocytosis, hypersegmented neutrophils.
What are the laboratory features of ineffective hematopoiesis in Vitamin B12 deficiency?
Increased unconjugated bilirubin, raised urine urobilinogen, reduced haptoglobins, raised serum lactate dehydrogenase.
What is folic acid?
“Folic acid is a yellow
What is the relationship between folate and cobalamin metabolism?
“Folate and cobalamin metabolism go hand in hand.”
What are some food sources of folate?
“Liver
How is folate destroyed during cooking?
“Folate is easily destroyed by heating
Where is folate absorbed?
“Folate is absorbed rapidly from the upper small intestine.”
What form do dietary folates convert to in the small intestine?
“5-methylTHF (5-MTHF).”
How is folate transported in the body?
“1/3 loosely bound to albumin (inactive)
What is the primary function of folate?
“Acts as coenzymes in the transfer of single-carbon units.”
Why should women of reproductive age take folic acid?
“To prevent neural tube defects
What happens if one of folate or cobalamin is deficient?
“If one is deficient
Which two body reactions require cobalamin?
“Methylmalonyl-CoA isomerization and methylation of homocysteine to methionine.”
What are clinical features of cobalamin-folate deficiency?
“Raised MCV
How is cobalamin-folate deficiency treated?
“With both vitamins in large doses
What is the recommended treatment for cobalamin deficiency?
“Six 1000 μg IM injections of hydroxocobalamin given every 3–7 days
What is the function of Vitamin C?
“Antioxidant activity
What are dietary sources of Vitamin C?
“Citrus fruits
What is the classic disease caused by Vitamin C deficiency?
“Scurvy.”
What are symptoms of scurvy?
“Fatigue
How is Vitamin C deficiency treated?
“200 mg/day of Vitamin C.”
What are functions of biotin?
“Gene expression
What are sources of biotin?
“Liver
What can cause biotin deficiency?
“Low dietary intake
What is the main function of choline?
“Precursor for acetylcholine
What are food sources of choline?
“Egg yolks
What is flavonoids’ role in human health?
“Antioxidant activity and potential prevention of chronic diseases like neurodegeneration
What are good food sources of flavonoids?
“Berries
What is Vitamin A primarily required for?
“Normal vision
What are dietary sources of Vitamin A?
“Liver
What are symptoms of Vitamin A deficiency?
“Night blindness
What are symptoms of Vitamin A toxicity?
“Acute: Increased intracranial pressure
What is the function of Vitamin D?
“Maintains function of non-skeletal tissues
What is the primary source of Vitamin D?
“The skin synthesizes Vitamin D upon UVB radiation exposure.”
What are classic signs of Vitamin D deficiency?
“Rickets
What is the upper intake limit for Vitamin D?
“4000 IU/day.”
What is the collective designation for vitamin E?
All stereoisomers of tocopherols and tocotrienols, although only the RR tocopherols meet human requirements.
What are the main functions of vitamin E?
Acts as a chain-breaking antioxidant, protects low-density lipoproteins and polyunsaturated fats from oxidation, inhibits prostaglandin synthesis, and affects protein kinase C and phospholipase A2 activities.
Where is vitamin E absorbed and metabolized?
It is taken up from chylomicrons by the liver and transported intracellularly by a hepatic α-tocopherol transport protein.
What are some common food sources of vitamin E?
Sunflower oil, safflower oil, wheat germ oil, soybean and corn oil, meats, nuts, cereal grains, fruits, and vegetables.
What is the RDA for vitamin E for adults?
15 mg/day (34.9 µmol or 22.5 IU).
In what conditions is vitamin E deficiency observed?
Severe and prolonged malabsorptive diseases like celiac disease, small intestinal resection, cystic fibrosis, cholestasis, and abetalipoproteinemia.
What are the symptoms of vitamin E deficiency?
Areflexia, hemolytic anemia, posterior column and spinocerebellar symptoms, peripheral neuropathy, ophthalmoplegia, skeletal myopathy.
How is vitamin E deficiency diagnosed in the lab?
By low blood levels of α-tocopherol: <5 µg/ml or <0.8 mg α-tocopherol per gram of total lipids.
What are some treatments for vitamin E deficiency?
Symptomatic treatment (800-1200 mg/day), water-miscible esters for children, antioxidants plus vitamin E for macular degeneration.
What are the toxicity risks associated with vitamin E?
High doses (>800 mg/day) may reduce platelet aggregation, interfere with vitamin K metabolism, and are contraindicated with warfarin and antiplatelet agents.
What is vitamin K1 also known as?
Phylloquinone.
What are the main functions of vitamin K?
Post-translational carboxylation of glutamic acid, necessary for calcium binding to γ-carboxylated proteins like prothrombin and clotting factors.
What are common food sources of vitamin K?
Green leafy vegetables (e.g., kale, spinach), margarine, liver, and vegetable oils (olive, canola, soybean).
What are symptoms of vitamin K deficiency in infants?
Hemorrhage, intracranial bleeding, and skin bleeding 1-7 days after birth.
How is vitamin K deficiency treated?
10 mg IV; chronic malabsorption may require 1-2 mg/day PO or IV per week.
What is zinc’s role in the body?
It is an integral component of metalloenzymes, involved in protein, DNA, and RNA synthesis, and essential for normal spermatogenesis and fetal development.
What inhibits zinc absorption?
Dietary phytate, fiber, oxalate, iron, copper, penicillamine, sodium valproate, and ethambutol.
What are common food sources of zinc?
Meat, shellfish, nuts, legumes, grains, and legumes (though zinc in grains and legumes is less bioavailable).
What are mild symptoms of zinc deficiency?
Stunted growth, decreased taste sensation (hypogeusia), and impaired immune function.
What is acrodermatitis enteropathica?
A rare autosomal recessive disorder with symptoms like diarrhea, alopecia, muscle wasting, depression, irritability, and a vesicular rash on extremities, face, and perineum.
What are zinc’s toxicity symptoms?
Nausea, vomiting, fever, hypochromic anemia, and anosmia (from intranasal preparations).
