While many nutrients are frequently touted for their muscle building properties, the mineral potassium is rarely mentioned in this regard. Nonetheless, studies have shown that taking potassium, especially during low-calorie diets, is associated with anti-catabolic actions. Potassium
may help the dieter maintain the acid-base balance of his body's tissues. Potassium and other minerals such as sodium and chloride are often referred to as "electrolytes" because of their essential role in nerve conduction and muscle contraction. Sodium is the primary electrolyte
outside the cell; potassium does its work inside the cell. The latter is essential to growth and constitutes five percent of the body's total mineral content. Potassium is required for protein synthesis. The mineral is also needed to convert glucose - the sugar circulating in blood
- into glycogen, which is stored in the liver and in muscles and is the body's source of complex carbohydrates. Glycogen is also the primary fuel used to power bodybuilding workouts.
Competitive bodybuilders are probably the one group most aware of the importance of taking potassium while dieting A low carbohydrate diet is like a natural diuretic - both promote the excretion of sodium and potassium. This! mineral excretion, coupled with a rapid breakdown of stored glycogen (which, in turn, is stored two and seven-tenths grams of water), is responsible for the rapid water-weight loss evident at the start of low-carb regimens. While the loss of water and sodium isn't problematic, excessive loss of potassium can rapidly lead to muscle weakness. These days, savvy bodybuilders supplement their low-carb diets with potassium to prevent such weakness. Potassium loss can be compounded by the use of diuretics, such as Lasix, which cause further potassium excretion. The result can be both muscle cramping and extreme weakness. A graphic example of that occurred at the 1994 Arnold Schwarzenegger Classic, when a competitor had to be carried offstage because he was feeling the effects of a Lasix injection he had taken just before the contest. As noted before, problems can occur even when potassium sparing diuretics, such as Aldactone, are abused. When pro bodybuilder Mike Matarazzo took such a diuretic in the final few days before be competed in the 1993 Arnold Classic, he didn't know how it would react with the large amounts of supplemental potassium he had been taking. His body retained potassium and he wound up with hyperkalemia (potassium excess), which was serious enough to require a brief hospitalization. Such unfortunate incidents highlight the serious problems that can arise when the body's delicate potassium balance is improperly manipulated. Potassium can also affect heart function. It's used as part of the lethal intravenous cocktail given to death-penalty inmates, and the material is also injected into heart-transplant patients to stop their hearts before surgery.
Potassium has an inverse relationship with sodium. Excess sodium causes potassium excretion and consequent water retention. An adrenal hormone called aldosterone promotes sodium retention and potassium excretion. Potassium sparing diuretics, such as Aldactone, work by blocking the effects of aldosterone (and testosterone, too, for that matter) Tbe body normally self monitor blood-potassium levels and regulates them accordingly. As noted, potasium imbalance (either too little or too much) can lead to heart-rhythm disturbances. In people with kidney disease, that self-monitoring mechanism also can fail, leading to retention of excess potassium, particularly when one takes supplemental amounts of this mineral Although the precise daily requirement for potassium is unknown, most scientists suggest a minimum daily intake of 2,000 milligrams.
A recent study, published in the journal Endocrinology (137 3738 43, 1996), examined the effects of potassium deficiency on testosterone production. Although the subjects in this study were male mice, much of the data maybe applicable to humans But the mice were castrated and decapitated, obviously, performing the same study with human volunteers would be impossible understand how a lack of potassium affects testosterone synthesis in lab animals, you need to know what governs the boss testosterone production Testosterone is manufactured mainly in the Leydig cells of the testes (and, to a lesser degree, in the adrenal glands), but the process is initiated by a burst of luteinizing hormone (LH), a pituitary hormone traveling in the blood to its target (the Leydig cells), Li-I turns on an enzyme that initiates an enzymatic cascade beginning with cholesterol and ending in testosterone (or estrogen in women). Without LH stimulation, there is no production of testosterone.
The Endocrinology study showed that if potassium is low, the pituitary gland will not secrete LH and testosterone synthesis will come to an abrupt halt. If, however, the mice were given either LH or human chorionic gonadotropin - which, in the testes, mimics the effects of LH - testosterone synthesis began again. The researchers who conducted the study aren't sure how a lack of potassium downgrade LH secretion They suspect that it may be connected to the role of potassium in stimulating the release of neurotrans mitters in the bran These In turn control the release of LH at regular intervals Mother possibility is that inadequate potassium may cause substances to be pro duced in the testes that inhibit testosterone synthesis. A lack of potassium also negatively affects the flow of other anabolic hormones, including growth hormone insulin growth factor. I Stress, increases the adrenal hormones cortisol and aldosterone, can also lead to lower potassium levels. And other studies show that intense exercise causes a loss of potassium Aim for a daily intake of 2,500 to 6,000 milligrams of potassium, with an absolute minimal intake of 2,000 milligrams Most fruits and vegetables are good dietary sources of potassium. The mineral is also present in pro severa tern sources such as beef liver and chicken (white meat). Eggs and cheese are a poor source The best supplemental sources are liquids, since tablets can be caustic.