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Potassium
DESCRIPTION
Potassium is essential in
maintaining nerve and muscle function.
FUNCTIONS
Potassium is an electrolyte
mineral which means that it has a part in controlling the
fluid level and acid/alkaline balance of the body and its
billions of cells. Potassium is kept inside the cell and is
counter-balanced by Sodium that remains outside the cell.
As well as maintaining fluid
and acid/alkaline balance, potassium (with Sodium is important
in maintaining the electrical potential that is so vital to
the transmission of nerve impulses and functioning of the
muscles.
DEFICIENCY
Potassium deficiency causes
weakness of the muscles and adversely affects the heart, causing
heart arrhythmias (irregular beats). Acute potassium loss
may even cause cardiac arrest. Mental confusion and Depression
can also result from potassium deficiency and there may be
an inability to concentrate urine. However, deficiency is
uncommon in normal situations, arising only from excessive
blood loss, sweating or Diarrhoea.
REQUIREMENTS
There is no EC C Recommended
Daily Allowance for potassium. The British RNI (Reference
Nutrient Intake) for adults is 3500mg.
SUPPLEMENTAL USES
Potassium may be deficient
in people who take certain diuretic medications, corticosteroids,
colchicine, and haloperidol. Such individuals may need to
take a potassium supplement. However, a doctor’s advice
should be sought first. Not all diuretics deplete potassium
and some may indeed encourage its retention within the body.
Athletes or manual workers
can also lose significant amounts of potassium through sweat
(2,3) and may benefit from a potassium supplement together
with other minerals (such as Calcium, Magnesium, etc.).
Long term use of certain
antibiotics (especially penicillin) may deplete potassium
and make a supplement advisable.
For people in general good
health and for whom the above situations do not apply, supplementation
with potassium is not normally advised except as part of a
full spectrum multivitamin and mineral tablet.
N.B. Most potassium supplements
provide little potassium in comparison with the recommended
daily requirement of 3500mg.
SAFETY
An intake of potassium above
17.6g daily has been shown to induce symptoms of potassium
overload in some individuals. This level represents a threshold
for acute toxicity.
INTERACTIONS AND CONTRA-INDICATIONS
Those with impaired kidney
or heart function, untreated Addison’s disease or taking
digitalis-type drugs should not take high-level potassium
supplements without medical supervision.
If taking ACE inhibitors,
avoid taking potassium without medical supervision.
FOOD
SOURCES - Potassium
Food (mg/100g)
Instant coffee 3780
Potato crisps 1190
Raisins 860
Potatoes 360
Pork 360
Cauliflower 350
Tomatoes 290
Chicken 290
Bread, wholemeal 230
Peas, frozen 190
Streaky bacon 183
Oranges 180
Milk, whole 140
Eggs 136
Cheese, cheddar 120
FOOD
SOURCES - Sodium
Food (mg/100g)
Instant coffee 81
Potato crisps 550
Raisins 52
Potatoes 8
Pork 65
Cauliflower 8
Tomatoes 3
Chicken 75
Bread, wholemeal 560
Peas, frozen 3
Streaky bacon 1245
Oranges 2
Milk, whole 50
Eggs 140
Cheese, cheddar 610
The Sodium contents are
also given above so as to indicate which foods are most suitable
for those on low Sodium /high potassium diets. It is particularly
of note that fruits and vegetables have very high potassium
to Sodium ratios.
REFERENCES
1. Haris A and Radó
J. [Potassium - sparing diuretics (spironolactone, triamterene,
amylorid)]. Orv Hetil, 137;35:1907-1914, 1996.
2. McKenna MJ et al. Effects of training on potassium, Calcium
and hydrogen. Iron regulation in skeletal muscle and blood
during exercise .Acta Physiol Scand, 156;3:335-346, 1996.
3. Otukonyong EE and Oyebola DD. Electrolyte loss during exercise
in apparently healthy Nigerians. Cent Afr J Med, 40;3:74-77,
1994.
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