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  » Diet Information  »  The principal micronutrients
Micronutrient Principal Sources Functions Effects of Deficiency and Toxicity Usual Therapeutic Dosage
Vitamin A As preformed vitamin: fish liver oils, liver, egg yolk, utter, cream, vitamin A - fortified margarine; as provitamin carotenoids: dark green leafy vegetables, yellow fruits, red palm oil Photoreceptor mechanism of retina, integrity of epithelia, lysosome stability, glycoprotein synthesis Deficiency:
Night blindness, perifollicular hyperkeratosis, xerophthalmia, keratomalacia, increased morbidity and mortality in young children
Toxicity:
Headache, peeling of skin, hepatosplenomegaly, bone thickening
10,000 - 20,000 µg (30,000-60,000 IU/day)
Vitamin D Ultraviolet irradiation of the skin is the major source; fortified milk is main dietary source; fish liver oils, butter, egg yolk, liver Calcium and phosphorus absorption; resorption, mineralization, and collagen maturation of bone; tubular reabsorption of phosphorus (?) Deficiency:
Rickets (tetany sometimes associated), osteomalacia
Toxicity:
Anorexia, renal failure, metastatic alcification
Primary deficiency:
10-40 µg (1400-1600 IU)/day vitamin D3
Metabolic deficiency:
1-2 µg/day 1,25-(OH) 2 D3 or 1a-(OH)D3
Vitamin E group Vegetable oil, wheat germ, leafy vegetables, egg yolk, margarine, legumes Intracellular antioxidant, scavenger of free radicals in biologic membranes Deficiency:
RBC hemolysis, neurologic damage, creatinuria, ceroid deposition in muscle.
Toxicity:
Interferes with enzymes, increased infection (?)
30-100 mg/day
Vitamin K
(activity)
Vitamin K1
phytonadione)
Vitamin K2
Leafy vegetables, pork, liver, vegetable oils, intestinal flora after newborn period Formation of prothrombin and other coagulation factors, normal blood coagulation Deficiency:
Hemorrhage from deficient prothrombin
Toxicity:
Kernicterus
In situation conducive to neonatal hemorrhage, 2-5 mg during labor or daily for 1 wk prior; or 0.5-1 mg to newborn
Essential fatty acids
(linolenic,
arachidonic acids)
Vegetable seed oils (corn, sunflower, safflower); margarines blended with vegetable oils Precursors of prostaglandins, leukotrienes, various hydroxy fatty acids, membrane structure Growth cessation, dermatosis Up to 10 gm/day
Thiamine
vitamin B1)
Dried yeast, whole grains, meat (especially pork, liver), enriched cereal products, nuts, legumes, potatoes Carbohydrate metabolism, central and peripheral nerve cell function, myocardial function Beriberi; infantile and adult (peripheral neuropathy, cardiac failure; Wernicke-Korsakoff syndrome) Dependency states 30-100 mg/day
Riboflavin
(vitamin B2)
Milk, cheese, liver, meat, eggs, enriched cereal products Many aspects of energy and protein metabolism, integrity of mucous membranes Cheilosis, angular stomatitis, corneal vascularization, amblyopia, sebaceous dermatosis 10-30 mg/day
Niacin
(nicotinic acid, niacinamide)
Dried yeast, liver, meat, fish, legumes, whole-grain enriched cereal products Oxidation-reduction reactions, carbohydrate metabolism Pellagra (dermatosis, glossitis, GI and CNS dysfunction) Niacinamide 100-1000 mg/day
Vitamin B6 group
(pyridoxine)
Dried yeast, liver, organ meats, whole-grain cereals, fish, legumes Many aspects of nitrogen metabolism, eg, transaminations, porphyrin and heme synthesis, tryptophan conversion to niacin; linoleic acid metabolism Deficiency:
Convulsions in infancy, anemias, neuropathy, seborrhea-like skin lesions; dependency states
Toxicity:
Peripheral neuropathy
25-100 mg/day
Folic acid Fresh green leafy vegetables, fruit, organ meats, liver, dried yeast Maturation of RBCs, synthesis of purines and pyrimidines Pancytopenia; megaloblastosis (especially pregnancy, infancy, malabsorption) 5-10 mg/day
Vitamin B12
(cobalamins)
Liver, meats (especially beef, pork, organ meats), egg, milk and milk products Maturation of RBCs; neural function; NDA synthesis, related to folate coenzymes; methionine and acetate synthesis Pernicious anemia, fish tapeworn and vegan anemias, sime psychiatric syndromes, nutritional amblyopia
Dependency states
100 µg/day for 7days, then 100µg twice weekly for 6 wks. Maintenance 100µg inj IM every month once for life.
Biotin Liver, kidney, egg yolk, yeast, cauliflower, nuts, legumes Carboxylation and decarboxylation of oxalocetic acid; amino acid and fatty acid metabolism Dermatitis, glossitis
Dependency states
150-300 µg/day
Vitamin C
(ascorbic acid)
Citrus fruits, tomatoes, potatoes, cabbage, green peppers Essential to osteoid tissue, collagen formation, vascular function, tissue respiration, and wound healing Scurvy (hemorrhages, loose teeth, gingivitis) 100-1000 mg/day
Sodium Wide distribution - beef, pork, sardines, cheese, green olives, corn bread, potato chips, sauerkraut Acid-base balance, osmotic pressure, blood pH, muscle contractility, nerve transmission, sodium pumps Deficiency:
Hyponatremia, confusion, coma
Toxicity:
Hypernatremia, confusion, coma

Normal 100mEq/day dietary.
Hyponatremia:
IV 0.9% N.saline (2-3L / 2-3 hrs) + 40mEq of Potassium and 45mEq of bicarbonate/L of 0.9% N.saline
Sodium toxicity:
1. Restrict daily dietary Sodium to 20-50mEq/day.
2. Increase Sodium Renal output using diuretics.
3. Improve Renal perfusion e.g. Digitalis in C.C.F.
Usually, these methods are combined.

Potassium Wide distribution - whole and skin milk, bananas, prunes, raisins Muscle activity, nerve transmission; intracellular acid-base balance and water retention Deficiency:
Hypokalemia, paralysis, cardiac disturbances
Toxicity:
Hyperkalemia, paralysis, cardiac disturbances
Normal 50-150mEq/day
Potassium deficiency:
Oral fresh coconut water juce, orange juce, tomatoes or bananas.
Potassium toxicity:
1. Avoid dietary Potassium i e, no protein diet.
2. inj. 5-10u of sol insulin + 50ml of 50% glucose IV over 5 mins + Sodium bicarbonate 45mEq over 5 mins rpt after 15 mins.
Calcium Milk and milk products, meat, fish, eggs, cereal products, beans, fruits, vegetables Bone and tooth formation, blood coagulation, neuromuscular irritability, muscle contractility, myocardial conduction Deficiency:
Hypokalemia and tetany; neuromuscular hyperexcitability
Toxicity:
Hyperkalemia, GI atony, renal failure, psychosis
10-30 mL 10% calcium gluconate solution IV in 24 h
Phosphorus Milk, cheese, meat, poultry, fish, cereals, nuts, legumes Bone and tooth formation, acid-base balance, component of nucleic acids, energy production Deficiency:
Irritability, weakness, blood cell disorders, GI tract and renal dysfunction
Toxicity:
Hyperphosphatemia in renal failure
Potassium acid and dibasic phosphate parenterally 600 mg (18.8 mEq)/day
Magnesium Green leaves, nuts, cereal grains, seafoods Bone and tooth formation, nerve conduction, muscle contraction, enzyme activation Deficiency:
Hypomagnesemia, neuromuscular irritability
Toxicity:
Hypermagnesemia, hypotension, respiratory failure, cardiac disturbances
2-4 mL 50% magnesium sulfate solution/day IM
Iron Wide distribution (except dairy products) - soybean flour, beef, kidney, liver, beans, clams, peaches
Much unavailable (< 20% absorbed)
Hemoglobin, myoglobin formation, enzymes Deficiency:
Anemia, dysphagia, koilonychias, enteropahty, decreased work performance, impaired learning ability
Toxicity:
Hemochromatosis, cirrhosis, diabetes, mellituse, skin pigmentation
Ferrous sulfate or gluconate 300 mg orally tid
Iodine Seafoods, iodized salt, dairy products
Water variable
Thyroxine (T4) and triiodothyronine (T3) formation and energy control mechanisms Deficiency:
Simple (colloid, endemic) goiter, cretinism, deaf-mutism, impaired fetal growth and brain development
Toxicity:
Occasional myxedema
150 mg iodine/day as potassium iodine added to salt
1:10-40,000 ppm
Fluorine Wide distribution - tea, coffee
Fluoridation of water supplies with sodium fluoride 1.0-2.0 ppm
Bone and tooth formation Deficiency:
Predisposition to dental caries, osteoporosis (?)
Toxicity:
Flurosis, mottling, pitting of permanent teeth; exostoses of spine
Sodium fluoride 1.1-2.2 mf/day orally
Zinc Wide distribution - vegetable sources
Much unavailable
Component of enzymes and insulin; skin integrity, wound healing, growth Deficiency:
Growth retardation, hypogonadism, hypogeusia, in cirrhosis, acrodermatitis enteropathica
30-150 mg/day zinc sulfate orally
Copper Wide distribution - organ meat, oysters, nuts, dries legumes, whole-grain cereals Enzyme component, hemopoiesis, bone formation Deficiency:
Anemia in malnourished children, Menkes' kinky hair syndrome
Toxicity:
Hepatolenticular degeneration, some biliary cirrhosis
0.3 mg/kg/day copper sulfate orally
Cobalt Green leafy vegetables Part of vitamin B12 molecule Deficiency:
Anemia in children (?)
Toxicity:
Cardiomyopathy
20-30 mg/day cobaltous chloride orally
Chromium Wide distribution - brewer's yeast Part of glucose tolerance factor Deficiency:
Impaired glucose tolerance in malnourished children; some diabetics and some elderly
200 mg/day chromium chloride orally
Selenium Meats and other animal products are reliable sources; soil concentration influences plant content Component of glutathione peroxidase Deficiency:
Cardiomyopathy of Keshan disease
Toxicity:
Loss of hair and nails, dermatitis, polyneuritis (?)
100 mg/day sodium selenite orally