Potassium is a metallic element with symbol K. Elemental potassium is a soft silvery-white alkaline metal. It reacts with air and water very rapidly producing enormous heat energy. Potassium is found in the form of ionic salts in the nature and found dissolved in seawater and in combination with the different minerals. Potassium ions are present in all the living cells. Diffusion of potassium ion is a vital mechanism in nerve transmission. Potassium is present in a huge amount in plant cells. The name potassium is derived from “Potash”, as it was first isolated from the ashes of plants. The agricultural soil can be deficient of potassium. So, the agriculture sector uses 95% global potassium produced chemically. If potassium depleted in animals, including humans, it can result in malfunction of various body systems.
Potassium is the 8th most abundant element in the body. An average human body contains about 120 grams of potassium. The human body contains as much potassium as a body has chlorine and sulfur, the major minerals; calcium and phosphorous are more abundant than potassium.
Potassium is found in many forms; some are found naturally while others are prepared synthetically. Potassium chloride is a white crystalline salt used to treat hypokalemia. Potassium bisulfate is a food preservative in the wine and beer making. It is also used in tanning leather, and in the textile industry. Potassium bromate is an oxidizing agent; it is used to improve dough strength and height. Potassium sodium tartrate is the main component of baking powder.
Potassium chloride can trigger three of the five taste sensations (sweet, bitter, salty, umami, and sour), so it can be detected by taste easily. Diluted solutions of potassium impart a sweet taste; like milk and juices, moderate concentrations of its ions give bitter or alkaline taste, while high concentrations give a salty taste. That’s why high-dose potassium supplements are less palatable.
Potassium is important in sending nerve impulses in all animals, and prevent muscle contraction. Potassium, calcium and sodium have an important role in the functioning of muscles. Potassium and sodium ions have somewhat similar chemical properties; cell membranes allow actively or passively one of the two ions to pass through while other ones are blocked by the membrane.
Potassium is an essential micronutrient in the human body, and is a major positive ion (cation) in the cells. It’s important in maintaining the electrolyte balance in the body. As discussed above potassium and sodium maintain the fluid balance in the body. Sodium (Na) ions make up the most of the positive ions of blood plasma, while potassium cations make up most of the cells fluid.
Glomerulus of the kidneys filtrate 180 liters of plasma every day, about 602 grams of sodium and 33 grams of potassium is filtered every day. Sodium and potassium reabsorption is necessary, and about 4-10 grams of sodium and 1-4 grams of potassium are reabsorbed. Reabsorption of sodium maintains the volume of the blood and keeps the osmotic pressure balance, while potassium reabsorption keeps the concentration of serum to an optimum level.
The potassium is a vital nutrient for human health. The United States Department of Agriculture lists tomato, orange, beet, bananas, beans, potatoes, etc. as the best source of dietary potassium. Other sources of dietary potassium include, apricot, chocolate, dried milk, almonds, pistachio, and avocado. Potassium chloride is used as alternate for sodium chloride (table salt) to the patients with hypertension, who want to limit the sodium chloride.