Comment [c33]: Pagination?
7. Healthnotes 1998-2002. Available from: URL: http://www.healthnotes.com.
8. Brewer G. Practical recommendations and new therapies for Wilson’s Disease. Drugs 1995;50:240-9.
9. Ryan J, McKillen M, Mason J. Sulphate/Molybdate interactions: In vivo and in vitro studies on the Group VI oxyanion transport
system in ovine renal tubule epithelial cells. Ann Rech Vet 1987;18(1):47-55.
10. Pitt MA. Molybdenum toxicity: interactions between Copper, Molybdenum and Sulphate. Agents Actions 1976;6(6):758-69.
11. Vyskocil A, Viau C. Assessment of Molybdenum toxicity in humans. J Appl Toxicol 1999;19(3):185-92.
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Meschino Health Comprehensive Guide to Minerals
Potassium
General Features
Potassium is the major cation (positively charged mineral) of intracellular fluid (within cells) with only small amounts in
the extracellular (outside of cells) fluid. Sodium and chloride are the major extracellular cations in the body, as the
sodium pump contained within the cell membrane continuously pumps sodium out of the cell to prevent the cell from
swelling up with water and bursting. The relative difference between the amount of sodium and chloride inside versus
outside the cell creates an electrical gradient that becomes important to the conduction of electrical impulses along
nerves and muscle cells for muscle contraction and nerve transmission. Together these three minerals also function to
regulate water and fluid balance throughout the body, blood pressure and pH balance. Potassium constitutes 5% of
the total mineral content of the body.
The hormone aldosterone hastens the resorption of sodium from the kidney with subsequent loss of Potassium in the
urine. This is one means through which aldosterone raises blood pressure. Potassium deficiency is rare due to its
availability from a wide variety of food, but excess fluid loss or a state of acidosis quickly deplete Potassium stores
leading to potential life-threatening conditions, such as cardiac failure. At the same time, Potassium supplementation
has a narrow margin of safety and must be tailored precisely to an individual’s need or grave consequences may
occur. Too much Potassium can weaken the heart muscle and pose a serious threat to life. As such, Potassium
supplementation requires proper monitoring by a health professional. In most cases Potassium supplementation is not
required as Potassium-rich foods are most often a bet er and safer way to replenish and maintain Potassium balance
in the body.1,2
Clinical Application and Mechanism of Action
Like sodium and chloride, Potassium is readily absorbed from the intestinal tract and excreted through the urine, feces,
and sweat. Eighty percent of absorbed Potassium is excreted in urine and 10-20% is excreted in the feces. Within the
body, it acts as a positively charged particle once dissolved in body fluids and is therefore, classified as a caution.1
Potassium is one of the body’s three major electrolytes, the other two being sodium and chloride. Electrolytes are
involved in intracellular osmosis, which means that they control the flow of body fluids into and out of tissues and cells.
As such, Potassium controls the distribution of water throughout the body with other electrolytes. Potassium and
sodium also influence blood pressure, irritability of muscle tissue and neuromuscular function. Potassium plays a
critical role in the transmission of electrical impulses in the heart and therefore, abnormal Potassium balance can lead
to heart arrhythmias, heart failure and sudden death heart at ack. Potassium also helps maintain pH balance
throughout the body and is required for the breakdown of glycogen into glucose.1,2
Deficiency State - Excessive loss of body fluids can result in Potassium deficiency. The loss may be due to vomiting,
diarrhea, excessive urination (e.g., diuretic drugs use or acidosis from uncontrolled diabetes mellitus or a high
protein/low carbohydrate diet) or prolonged malnutrition. In these cases, intracellular Potassium is transferred from
inside to outside of the cell as ionized Potassium in the extracellular fluid, where it is then excreted from the body
during fluid loss. The chief features of deficiency are muscular weakness and mental apathy. In hypokalemia (low
blood levels of Potassium) cardiac failure can result from inadequate Potassium in heart muscle.1 Some very low
calorie diets and high protein/low carbohydrate diets have resulted in death of subjects, due to advanced or rapid
Potassium loss, followed by cardiac arrest. As such, certain precautions regarding vitamin and mineral replenishment
should be utilized when following programs of this nature.3,4,5,6
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Meschino Health Comprehensive Guide to Minerals
Dosage and Standardized Grade
A normal adult requires between 800 mg and 1,500 mg of Potassium per every 1,000 calories consumed. This level of
intake is easily met through the Potassium occurring naturally in milk, meats, cereals, vegetables, and fruit. Of note is
the fact that one banana or orange contains at least 500 mg of Potassium. Many authorities suggest using foods rich
in Potassium as the primary way to replenish Potassium, as Potassium supplements represent a potentially dangerous
approach to Potassium repletion.
The amount of Potassium usually consumed in the diet ranges from 2,500 to 5,800 mg per day.1,2
Increased Potassium Needs:
1. High Blood Pressure: Evidence exists to support the view that the high sodium to Potassium intake of the North
American diet is a major contributing factor to the high incidence of hypertension (high blood pressure) in modern
society. Diets that emphasize a reduction in sodium intake and a greater reliance upon Potassium-rich foods
(fruits, vegetables, rice) have revealed that these interventions can help to lower high blood pressure in certain
individuals with sodium-sensitive hypertension. Note that Potassium supplementation is not required to at ain this
ef ect.7,8,9 However, the use of calcium supplementation (1,000-1,500 mg per day) and magnesium
supplementation (400-600 mg per day) can help to increase the excretion of sodium through the kidneys and have
been shown to lower blood pressure in sodium-sensitive hypertensive patients through this means (see Calcium
and Magnesium in this document).
2. Kidney Stones: Evidence exists to support the notion that a diet higher in Potassium-rich foods may help to reduce
the risk of kidney stones.10
Adverse Side Effects, Toxicity and Contraindications
Potassium toxicity, known as hyperkalemia, occurs in kidney failure, where the kidney is unable to filter Potassium in a
normal manner, and Potassium is then allowed to build up in the bloodstream to abnormally high levels. This results in
mental confusion, numbness of extremities, poor respiration and weakening of heart action. This is one reason why
the indiscriminate use of Potassium supplements may spell trouble. Anyone with kidney damage is a candidate for
Potassium toxicity and requires professional assistance in determining their specific dietary Potassium and protein
needs.1,2
Potassium supplements at high levels (several hundred mgs at one time in tablet form) can produce severe stomach
irritation--a problem not encountered with Potassium in food. Thus, it is wise to use food as the exclusive means to
ingest Potassium, unless otherwise prescribed by an attending physician.2
Individuals on Potassium-sparing drugs should avoid Potassium-chloride products contained in various salt substitute
products. Even too much fruit consumption can lead to hyperkalemia in these patients and thus, these cases require
specific dietary instructions from the at ending physician in regards to Potassium-rich foods and the use of Potassium
supplements.
Due to the potential dangers and side ef ects of Potassium supplementation, the Food and Drug Administration allows
only 99 mg in a single Potassium tablet, sold as a supplement. This is only a small fraction of the RDA for Potassium,
and highlights the seriousness that Potassium supplementation is viewed by health authorities.2
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Meschino Health Comprehensive Guide to Minerals
Drug-Nutrient Interactions
A large number of medications are known to cause Potassium depletion in the body, and therefore, the prescribing
physician should make recommendations as to the need for increased intake of Potassium-rich foods on a case-by-
case basis. Medications that deplete Potassium include:
Albuterol: Used in renal failure to treat hyperkalemia11
Aminoglycosides: Antibiotics such as streptomycin and neopmycin12
Amphotericin B13
Salicylates (ASA containing drugs)14
Bisacodyl (laxative ef ects)15
Colchicine: Used for Gout16
Corticosteroids (e.g., prednisone)17
Foscarnet18
L-Dopa: Used in Parkinson’s Disease19
Loop Diuretics (e.g., furoseminde, bumetanide, ethacrynic acid, torsemide)20
Calcium Channel Blockers: Used to treat hypertension (e.g., amlodipine, bepridil, verapamil)21,22
Penicillins23
Ritodrine24
Sodium Bicarbonate25
Terbutaline24
Thiazide Diuretics (e.g., chlorothiazide, hydrochlorothiazide, metolazone)26
Pregnancy and Lactation
During pregnancy and lactation, the only supplements that are considered safe include standard prenatal
vitamin and mineral supplements. All other supplements or dose alterations may pose a threat to the
developing fetus and there is generally insuf icient evidence at this time to determine an absolute level of
safety for most dietary supplements other than a prenatal supplement. Any supplementation practices
beyond a prenatal supplement should involve the cooperation of the at ending physician (e.g., magnesium
and the treatment of preeclampsia.)
References: Pregnancy and Lactation
1. Encyclopedia of Nutritional Supplements. Murray M. Prima Publishing 1998.
2. Reavley NM. The New Encyclopedia of Vitamins, Minerals, Supplements, and Herbs. Evans and
Company Inc. 1998.
3. The Healing Power of Herbs (2nd edition). Murray M. Prima Publishing 1995.
4. Boon H and Smith M. Health Care Professional Training Program in Complementary Medicine.
Institute of Applied Complementary Medicine Inc. 1997.
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Meschino Health Comprehensive Guide to Minerals
1. Standard Textbooks of Nutritional Science:
2. Shils M, Shike M, Olson J, Ross C. Modern Nutrition in Health and Disease. 9th ed. Baltimore, MD: Lippincott Williams & Wilkins;
1993
3. Escott-Stump S, Mahan LK, editors. Food, Nutrition and Diet Therapy. 10th ed. Philadelphia, PA: W.B. Saunders Company; 2000
4. Bowman B, Russell RM, editors. Present Knowledge in Nutrition, 8th ed. Washington, DC:.ILSI Press; 2001
5. Kreutler PA, Czajka-Narins DM, editors. Nutrition in Perspective. 2nd ed. Upper Saddle River, NJ: Prentice Hall Inc.; 1987
6. Wahr JA, Parks R, Boisvert D, et al. Preoperative serum potassium levels and perioperative outcomes in cardiac surgery patients.
JAMA 1999;281:2203-10
7. Stein K. High-protein, low-carbohydrate diets: Do they work? J Am Diet Assoc 2000;100:760-1
8. Gould KL, Ornish D, Scherwitz L et al. Changes in myocardial perfusion abnormalities by positron emission tomography after long-
term, intense risk factor modification. JAMA 1995;274:894-901
9. Fleming RM, Boyd LB. The effect of high protein diets on coronary blood flow. Angiology 2000;51(10):817-26
10. Mot e G. Arrhythmia Caused by Potassium Deficiency. Arch Mal Coeur Vaiss Apr1984;77(Spec No):17-22
11. Cutler JA. The effects of reducing sodium and increasing potassium intake for control of hypertension and improving health. Clin Exp
Hypertens Jul1992;21(5-6):769-83
12. Langford HG. Dietary potassium and hypertension: Epidemiologic data Am Intern Med 1983;98(2):770-2
13. Kawano Y et al. Effects of potassium supplementation on office, home, and 24-h blood pressure in patients with essential
hypertension. Am J Hypertens Oct1998;11(10):1141-6
14. Curhan GC et al. A prospective study of dietary calcium and other nutrients and the risk of symptomatic kidney stones. N Engl J Med
Mar1993;328(12):833-8
15. Montoliu J et al. Potassium-lowering effect of albuterol for hyperkalemia in renal failure. Arch Intern Med Apr1987;147(4):713-7
16. Kes P, Reiner Z. Symptomatic hypomagnesemia associated with gentamicin therapy. Magnes Trace Elem 1990;9(1):54-60
17. Physicians’ Desk Reference. 53rd ed. Montvale NJ:Medical Economics Company Inc;1999:1038
18. Nain CK et al. Acetylsalicylic Acid Acid-induced biochemical changes in gastric juice: a failure of adaptation? Indian J Gastroenterol
Jan1998;17(1):4-5
19. Ritsema GH et al. Potassium supplements prevent serious hypokalaemia in colon cleasning. Clin Radiol Dec1994;49(12):874-6
20. Race TF et al. Intestinal Malabsorption induced by oral colchicines. Comparison with neomycin and cathartic agents. Am J Med Sci
Jan1970;259(1):32-41
21. Shenfield GM et al. Potassium supplements in patients treated with corticosteroids. Br J Dis Chest Jul1975;69:171-6
22. Malin A et al. Foscarnet-induced hypokalaemia. J Infect Nov1992;25(3):329-30
23. Granerus AK, Jagenburg R, Svanborg A. Kaliuretic effect of L-dopa treatment in parkinsonian patients. Acta Med Scand
1977;201(4):291-7
24. Lindeman RD. Hypokalemia:causes, consequences and correction. Am J Med Sci Aug1976;272(1):5-17
25. Tishler M, Armon S. Nifedipine-induced hypokalemia. Drug Intell Clin Pharm may1986;20(5):370-1
26. Minella RA et al. Ratal Verapamil Toxicity and Hypokalemia. Am Heart J Jun1991;121(6Pt1):1810-12
27. Gill MA et al. Hypokalemic, metabolic alkalosis induced by high-dose ampicillin sodium. Am J Hosp Pharm may 1977;34(5):528-31
28. Braden GL et al. Ritodrine- and terbutaline-induced hypokalemia in preterm labor: mechanisms and consequences. Kidney Int
Jun1997;51(6):1867-75
29. Fitagibbons LJ, Snoey ER. Severe metabolic Alkalosis due to baking soda ingestion: case reports of two patients with unsuspected
antacid overdoes. J Emerg Med Jan1999;17(1):57-61
30. Petri M et al. The metabolic effects of thizide therapy in the elderly: a population study. Age Ageing May 1986;15(3):151-5
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Meschino Health Comprehensive Guide to Minerals
Selenium
General Features
Selenium is present in all the tissue of the body and is most highly concentrated in the kidneys, liver, spleen, pancreas
and testes. It is readily absorbed and excreted in urine and feces.
Levels of soil selenium vary greatly from country to country. There are low levels in Europe, parts of the United States,
New Zealand and parts of China. There are high levels in Japan, Thailand, Philippines and Puerto Rico. In rural
China, where selenium levels are very low, children are susceptible to a specific cardiomyopathy known as Keshan
disease. Keshan disease is characterized by multiple focal myocardial necroses, likely caused by free-radical
damage. Patients with Keshan disease have lower blood levels of selenium than people elsewhere in the world. A
prevention program to reduce the incidence of Keshan disease has employed the use of selenium supplementation. It
has been very ef ective at reducing the incidence of Keshan disease in children in China and has shown benefits in
New Zealand as well.
The most well known function of selenium is that it is an important constituent of the antioxidant enzyme, glutathione
peroxidase. Glutathione peroxidase protects against accumulation of hydrogen peroxide, which can undergo further
biochemical transformation to yield the very aggressive and damaging reactive oxygen species known as hydroxy-
radicals.1
Some studies indicate that individuals living in areas where the selenium soil concentration is high and/or have higher
blood levels of selenium, experience a lower incidence of cancer.2,3
Animal and laboratory studies indicate that selenium has other cancer-protective (chemoprevention) ef ects in addition
to antioxidant enzyme activation. These include the induction of apoptosis (programmed cell death of cancer cells),
decreased synthesis of prostaglandin series-2, and immune system modulation.4,5
Due, primarily, to its effects on antioxidant function selenium has received much attention as a nutrient that may help
to prevent cancer, heart disease, cataracts, reduce inflammatory diseases and help stimulate immune function in
immune-compromised patients (e.g., HIV infection).6
Absorption and Metabolism
Absorption of selenium appears to be under no physiological control. Absorption of selenium, given as selenite
solutions is greater than 90 percent and is possibly 100 percent, according to some human studies. It is also readily
excreted to help prevent states of toxicity. The body stores only a few micrograms of selenium in all of the body tissue
combined.7
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Meschino Health Comprehensive Guide to Minerals
Recommended Daily Al owance (Selenium)
Age Group
Dosage (mcg)
0-6 mths
10
6-12 mths
15
1-6 yrs
20
7-10 yrs
30
Males 11-14
40
Males 15-18
50
Males 19 and over
70
Females 11-14
45
Females 15-18
50
Females 19 and over
55
Pregnant females
65
Lactating females
756
Supplementation Studies and Clinical Applications