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.
