A) FLUID BALANCE AND SODIUM REGULATION
The vast majority (approximately 98%) of the potassium in the body is found within the cells. Intracellular potassium maintains a proper balance in the fluid concentrations within cells. This is accomplished by regulating the quantities of sodium that can enter cells. Most of the sodium in the body functions in the extracellular regions. Among other things, sodium helps maintain proper volume of body fluids. However, if the intracellular level of sodium becomes excessive, fluid retention can occur and the cells can become damaged or even destroyed through fluid engorgement. An increase in potassium and reduction in sodium intake can help reduce such a cellular imbalance. However, in some individuals the cells remain relatively unresponsive to manipulation of sodium and potassium intake alone. When this occurs, it is often due to a deficiency in magnesium; magnesium triggers a mechanism which pumps sodium out of the cells and potassium into the cells. As a result, when there is an excess of intracellular sodium and commensurate lack of cellular potassium it is often recommended that magnesium supplementation is combined with an increased potassium intake and lower sodium intake.
B) NEUROMUSCULAR HEALTH AND FUNCTION
Like magnesium and calcium, potassium is essential for proper function of the nerves and muscles. Potassium works with sodium to trigger nerve impulses by influencing cellular ‘electricity’. Among other relevant functions, both calcium and magnesium influence the neurological chemical messengers (neurotransmitters) that ensure proper nerve transmission. When a nerve is stimulated by neurotransmitters, potassium leaves the cell and sodium enters. The electrical charge that results from this electrolyte exchange conducts impulses down the nerve axon, which in turn can trigger muscle contraction. Potassium deficiency also impairs storage of glycogen (the form of glucose that fuels muscle function), which not surprisingly can lead to muscle fatigue, weakness and poor muscular performance. The influence of potassium on muscle function, sodium balance and glycogen storage is especially important to the health of the heart and blood vessels (see cardiovascular health and function below).
C) CARDIOVASCULAR HEALTH AND FUNCTION
The beneficial effect of potassium on cardiovascular health primarily stems from its influence on regulation of muscle contraction and fluid levels. As mentioned above, potassium boosts muscle glycogen storage and helps trigger nerve impulses that stimulate muscle contraction. In this respect, this mineral is necessary for vascular contraction and a cardiac pumping action that is strong and efficient. This may help explain the strong association between potassium deficiency and conditions such as heart arrhythmias and congestive heart failure. The ability of potassium to reduce fluid retention can generally influence cardiovascular health, but is especially pivotal in the maintenance of normal blood pressure. There is a strong scientific correlation between potassium and sodium status and blood pressure. This is not only the case in individuals with cardiovascular disease or a history of hypertension. One interesting crossover study of men with normal blood pressure showed that a manipulation of dietary potassium and sodium intake had a substantial impact on blood pressure. When the men were put on a low potassium diet they experienced a significant increase in blood pressure compared to when they were consuming the normal potassium diet. They were given a loading dose of sodium at a particular stage while consuming both the low and normal potassium diet. It is worth noting that the infusion of sodium further raised the blood pressure during the low potassium diet but not during the normal potassium phase. It is also interesting to note that the influence of potassium balance on blood pressure is not restricted to adults. A 1990 study of 233 children showed (over an average observational period of seven years) that blood pressure was measurably higher during the periods when their potassium intakes were lower.
Please note: Although manipulating potassium and sodium intake can provide considerable benefit in blood pressure control, research exclusively employing potassium supplements has led to mixed results. Reviews of this research suggest that when sodium is not being restricted, potassium supplements are more likely to be effective in black people than white people. Though sodium restriction is warranted in both groups, many (if not most) hypertensive people are not sodium sensitive (i.e. their blood pressure is not significantly affected by manipulation of sodium intake alone). In any case, it would seem prudent for both black and white people with hypertension to both decrease sodium intake and increase potassium intake.
D) STRESS PROTECTION
The body’s response to stress (controlled by adrenal hormones) has three main phases – alarm, resistance and exhaustion. After the short-lived alarm phase, the resistance phase allows the body’s stress adaptation to be maintained for longer periods. Unfortunately, the hormonal response to this phase (especially aldosterone release) causes a significant depletion of cellular potassium and retention of sodium – one of the main factors leading to the symptoms associated with the exhaustion phase of stress. Especially in individuals who experience chronic stress, the long-term depletion of potassium can lead to fatigue and exhaustion, hypertension and other cardiovascular problems, neurological and muscular problems, etc. Replacement of potassium stores is critical to counteracting the long-term negative health implications of chronic stress.
Potential Applications
• Cardiovascular health – general (see Contraindications/Cautions below)
• High blood pressure
• Fluid retention
• Fatigue
• Exhaustion
• Muscle weakness
• Sports nutrition
• Stress
Typical Supplemental Dosage Range
• 50-99mg elemental potassium per day*
Common Food Sources
• Bananas
• Oranges
• Avocado
• Potatoes
• Lima Beans
• Plums
• Mushrooms
• Watercress
• Parsley
EC RDA
• None established'””*
Although there is no established RDA, a dietary intake range of approximately 2000-5OOOmg per day is often recommended.
Common Supplement Forms/Sources
• Potassium chloride
• Potassium bicarbonate
• Potassium gluconate
• Potassium citrate
• Potassium aspartate
* Although a supplemental daily dosage of 50-99mg per day bears no resemblance to the recommended dietary intake range of 2000-5OOOmg per day, certain governments restrict the amounts of potassium that can be put into a dietary supplement. This is evidently due to the concerns regarding potential side effects and toxicity of high doses of potassium salts (see Contraindications/Cautions below).
they be consumed in a ratio of at least 5:1 potassium to sodium (some believe that even higher potassium is better still for optimal health). Unfortunately, the typical ‘western’ diet contains more sodium than potassium. Although recommendations vary, it is often suggested that adult dietary consumption of potassium fall between approx. 2000-5000mg per day, with a sodium intake of between 500-1000mg per day. Exceptions include those who lose significantly higher than average amounts of one or both minerals, such as through heavy perspiration, strenuous exercise, diarrhoea, potassium-draining diuretics, laxatives, severe stress, etc.
Contraindications/Cautions/lnteractions/Toxicity Concerns
• Patients with kidney disease should not take potassium unless on the advice and under the strict monitoring of their physician.
• Especially in those with defects in potassium excretion (i.e. kidney disease), potassium toxicity can lead to muscle weakness, appetite loss, hypotension, paralysis of legs and/or arms, irregular heart beat, coma or even fatal renal or cardiac failure.
• For the average person, potassium toxicity may occur if dietary intake and/or supplemental daily intake exceeds 18 grams (18,000mg.), although it is worth noting that potassium toxicity is very rare in individuals with normal renal function.
• Unless on the advice and under the strict monitoring of a physician, very high doses are also not recommended in patients with digestive system ulcers, intestinal obstruction, severe dehydration, serious burns, heart blockage or Addison’s Disease.
• High doses of potassium should not be used by people taking ACE inhibitor medication, potassium- sparing diuretics, NSAIDs (especially in the elderly), heparin or trimethoprim/ sulfamethoxazole unless on the advice and under the strict monitoring of a physician.
• There are reports that the drug haloperidol may either raise or lower potassium levels; potassium status should be checked prior to increasing potassium intake if taking haloperidol.
• Supplements or medications containing high doses of potassium salts (potassium chloride, etc) may in some people cause abdominal cramping, diarrhoea, nausea and/or vomiting. Digestive ulcers may also occur, especially in those taking high doses of modified-release potassium. Such symptoms will generally not occur with equivalent amounts of potassium from food sources.
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