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Other common
name(s): none
Scientific/medical
name(s): K, K+, potassium chloride (KCl), potassium
citrate, potassium acetate, potassium carbonate, potassium gluconate,
potassium bicarbonate
Description
Potassium is an essential mineral found in most foods. Along
with sodium and calcium, potassium helps regulate major body functions,
including normal heart rhythm, blood pressure, water balance in the
body, digestion, nerve impulses, muscle contractions, and pH balance
(the balance of acidity and alkalinity in the body). The body cannot
manufacture potassium on its own and must obtain it from foods.
Potassium is found in foods such as apricots, potatoes, bananas,
oranges, pineapples, green leafy vegetables, whole grains, beans, nuts,
and lean meat. Most salt substitutes also contain large amounts of
potassium.
Overview
Potassium is a mineral that is required for normal body
functioning. Most people get all the potassium they need in their diet.
Available scientific evidence does not support claims that potassium
supplements can prevent or treat cancer in humans. Excess potassium in
the body can be toxic.
How is it promoted for use?
Some alternative medical practitioners maintain that low
levels of potassium in the body may be linked to cancer, heart disease,
high blood pressure, osteoporosis, depression, and schizophrenia. Some
proponents claim that a diet high in sodium and low in potassium
promotes tumor growth by changing the normal pH and water balance in
human cells.
What does it involve?
Because most foods contain potassium, people usually get
plenty of potassium from their normal food intake. Normally, the
kidneys control the level of potassium in the blood and eliminate
excess in the urine. The Food and Nutrition Board of the National
Academies of Sciences has not set a Recommended Daily Allowance for
potassium, but has set Adequate Intake at 4.7 grams per day for most
adults. There is no upper limit for potassium intake from food alone,
but people with kidney disease, Addison’s disease, or those
taking certain blood pressure medicines may need to consume less than
the Adequate Intake of potassium.
Potassium supplements are needed only by those who have low
levels of potassium in their bloodstream, a condition known as
hypokalemia. The causes of hypokalemia can include diarrhea and
vomiting, diabetes, certain kidney diseases, excessive sweating,
overuse of laxatives, and some types of diuretics (drugs that remove
water from the body through urine). Use of potassium supplements can be
dangerous unless monitored by health care providers.
What is the history behind it?
In the 1930s, Max Gerson began developing a controversial
dietary treatment for cancer known as the Gerson Diet Therapy (see Gerson Therapy).
The cornerstone of his diet was the use of potassium supplements and
low sodium intake. He claimed the diet could restore proper balance of
salt and water within human cells and help stop tumor growth. However,
this theory has not been supported by clinical or experimental data.
What is the evidence?
Some animal and human studies have indicated that eating foods
high in potassium and low in sodium might help prevent high blood
pressure, or hypertension. Dietary Approaches to Stop Hypertension, the
so-called DASH diet, was designed to help control blood pressure. The
DASH diet can reduce blood pressure and risk of heart disease through
weight loss, reduced salt intake, moderation in drinking alcohol (for
those who drink), and eating foods that are rich in potassium. These
measures are especially helpful in older people and in African
Americans, although the exact reasons are uncertain. For people who
already have hypertension, these measures can be used along with
medicines to gain better control over blood pressure. This can help
reduce risk of stroke and heart attack.
Some population studies have found that in a number of
countries where there are high-potassium diets, cancer rates are lower.
In areas where there are low-potassium diets, these studies showed the
cancer rates are higher. These types of studies, however, do not prove
a direct connection, because there are many other factors involved. A
few epidemiologic studies of individual potassium intake (rather than
national averages) have found associations with cancer risk. However,
the main sources of dietary potassium are fruits and vegetables, so
people with a diet high in potassium may be at lower risk for cancer
because of their intake of other beneficial phytochemicals. In
addition, because these studies estimated potassium intake from food
sources, the results are of uncertain relevance to potassium
supplements.
One researcher has suggested a link between low potassium and
high sodium levels in cells and an increased risk of cancer. However,
available scientific evidence does not support the idea that changes in
dietary potassium intake have any impact on potassium concentrations
inside cancer cells. Further studies are needed to learn the effects of
a high-potassium, low-sodium diet on the prevention or formation of
cancer.
Are there any possible problems or
complications?
This product is sold as a
dietary supplement in the United States. Unlike companies that produce
drugs (which must provide the FDA with results of detailed testing
showing their product is safe and effective before the drug is approved
for sale), the companies that make supplements do not have to show
evidence of safety or health benefits to the FDA before selling their
products. Supplement products without any reliable scientific evidence
of health benefits may still be sold as long as the companies selling
them do not claim the supplements can prevent, treat, or cure any
specific disease. Some such products may not contain the amount of the
herb or substance that is written on the label, and some may include
other substances (contaminants). Though the FDA has written new rules
to improve the quality of manufacturing processes for dietary
supplements and the accurate listing of supplement ingredients, these
rules do not take full effect until 2010. And, the new rules do not
address the safety of supplement ingredients or their effects on health
when proper manufacturing techniques are used.
Most such
supplements have not been tested to find out if they interact with
medicines, foods, or other herbs and supplements. Even though some
reports of interactions and harmful effects may be published, full
studies of interactions and effects are not often available. Because of
these limitations, any information on ill effects and interactions
below should be considered incomplete.
Excessive use of potassium supplements or salt substitutes can
cause potassium to build up in the blood, resulting in a condition
known as hyperkalemia. The symptoms of hyperkalemia include muscle
weakness, numbness and tingling, abnormal heart rhythm, muscle
paralysis, trouble breathing, and even heart failure and death. Severe
kidney failure and Addison’s disease (a hormone deficiency)
may also cause hyperkalemia. However, even people with normal kidneys
can overdose on potassium if they take too many supplements at once.
People who are taking potassium-sparing diuretics (such as
triamterene, amiloride, and spironolactone) or ACE inhibitors (such as
lisinopril, enalapril, and captopril) can build up dangerously high
potassium levels by using potassium supplements or salt substitutes.
Those with kidney failure, diabetes, or Addison’s disease
should only take potassium supplements under the careful supervision of
a doctor.
Other side effects of potassium supplements may include
stomach or intestinal irritation, nausea, vomiting, abdominal pain,
gas, and diarrhea. Talk with your doctor or pharmacist if you are
thinking about potassium supplements. Relying on this type of treatment
alone and avoiding or delaying conventional medical care for cancer may
have serious health consequences.
Additional Resources
More information from your American Cancer
Society
The following information on complementary and alternative
therapies may also be helpful to you. These materials may be found on
our Web site (www.cancer.org)
or ordered from our toll-free number (1-800-ACS-2345).
References
Appel LJ, Brands MW, Daniels SR, Karanja N, Elmer PJ, Sacks
FM; American Heart Association. Dietary approaches to prevent and treat
hypertension: a scientific statement from the American Heart
Association. Hypertension.
2006;47:296-308.
Braunwald E, Fauci AS, Kasper DL, Hauser SL, Longo DL, Jameson
JL, eds. Harrison’s
Principles of Internal Medicine. 15th ed. Washington DC:
McGraw-Hill; 2001.
Cassileth B. The
Alternative Medicine Handbook: The Complete Reference Guide to
Alternative and Complementary Therapies. New York, NY:
W.W. Norton; 1998.
Grimm RH Jr, Neaton JD, Elmer PJ, Svendsen KH, Levin J, Segal
M, Holland L, Witte LJ, Clearman DR, Kofron, et al. The influence of
oral potassium chloride on blood pressure in hypertensive men on a
low-sodium diet. N Eng
J Med. 1990;322:569-574.
Food and Nutrition Board, Institute of Medicine, National
Academies of Science. Dietary reference intakes (dris): recommended
intakes for individuals, elements. Institute of Medicine Web site.
http://www.iom.edu/Object.File/Master/21/372/DRI%20Tables%20after%20electrolytes%20plus%20micro-macroEAR_2.pdf.
Accessed June 6, 2008.
Jacobs MM. Potassium inhibition of DMH-induced small
intestinal tumors in rats. Nutr
Cancer. 1990;14:95-101.
Jansson B. Potassium, sodium, and cancer: a review. J Environ Pathol Toxicol Oncol.
1996;15:65-73.
Levi F. Pasche C. Lucchini F. La Vecchia C. Dietary intake of
selected micronutrients and breast-cancer risk. Int J Cancer.
2001;91:260-263.
Negri E, La Vecchia C, Franceschi S, D’Avanzo B,
Talamini R, Parpinel M, Ferraroni M, Filiberti R, Montella M, Falcini
F, Conti E, Decarli A. Intake of selected micronutrients and the risk
of breast cancer. Int J
Cancer. 1996;65:140-144.
Potassium. PDRhealth Web site.
http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/pot_0208.shtml.
Accessed June 6, 2008.
Tobian L. Dietary sodium chloride and potassium have effects
on the pathophysiology of hypertension in humans and animals. Am J Clin Nutr.
1997;65:606S-611S.
Van Leer EM, Seidell JC, Kromhout D. Dietary calcium,
potassium, magnesium and blood pressure in the Netherlands. Int J Epidemiol.
1995;24:1117-1123.
Note: This information may not cover
all possible claims, uses, actions, precautions, side effects or
interactions. It is not intended as medical advice, and should not be
relied upon as a substitute for consultation with your doctor, who is
familiar with your medical situation.
Last Medical Review: 11/01/2008
Last Revised: 11/01/2008
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