Potassium - Periodic Table of Videos

Potassium is an "evil" element, but it's crucial to life. In this video see some violent explosions and the gentle creation of a potassium mirror. More chemistry at www.periodicvideos.com Follow us on Facebook at www.facebook.com And on Twitter at twitter.com Periodic Videos films are by video journalist Brady Haran

Potassium and sodium are chemically very similar. For this reason it took a long time before their salts were differentiated. The existence of multiple elements in their salts was suspected from 1702, and this was proven in 1807 when potassium and sodium were individually isolated from different salts by electrolysis. Potassium in nature occurs only in ionic salts. As such, it is found dissolved in seawater (which is 0.04% potassium by weight, and as part of many minerals. Most industrial chemical applications of potassium employ the relatively high solubility in water of potassium compounds, such as potassium soaps. Potassium metal has only a few special applications, being replaced in most chemical reactions with sodium metal.

Potassium ion is necessary for the function of all living cells. Potassium ion diffusion is a key mechanism in nerve transmission, and potassium depletion in animals, including humans, results in various cardiac dysfunctions. Potassium is found in especially high concentrations within plant cells, and in a mixed diet, it is mostly concentrated in fruits. The high concentration of potassium in plants, associated with comparatively low amounts of sodium there, historically resulted in potassium first being isolated from potash, the ashes of plants, giving the element its name. Heavy crop production rapidly depletes soils of potassium, and agricultural fertilizers consume 95% of global potassium chemical production.

Potassium lowers blood pressure

Blood pressure (BP) is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs.Blood pressure drops most rapidly along the small arteries and arterioles, and continues to decrease as the blood moves through the capillaries and back to the heart through veins. Gravity, valves in veins, and pumping from contraction of skeletal muscles are some other influences on BP at various places in the body.
The measurement blood pressure without further specification usually refers to the systemic arterial pressure measured at a person's upper arm. It is measured on the inside of an elbow at the brachial artery, which is the upper arm's major blood vessel that carries blood away from the heart. A person's BP is usually expressed in terms of the systolic pressure over diastolic pressure (mmHg), for example 140/90.

It’s been common knowledge that eating fruits and vegetables is good for you, but now there is yet another reason to eat your peas (or bananas). A new study from St. George’s Medical School in London, published in the April 2005 issue of Hypertension, compared the blood-pressure-lowering effects of potassium chloride against the effects of potassium citrate. The results of this study showed that potassium citrate has the same blood-pressure-lowering effect as potassium chloride, which has been proven in the past to lower blood pressure. Potassium chloride, however, must be taken as a dietary supplement, whereas potassium citrate is found naturally in many foods.
The study tested the effects of potassium chloride and potassium citrate on 14 adults with an average starting blood pressure of 151/93, placing them in the category of Stage 1 hypertension. The volunteers were randomly split into two groups; one group was given potassium chloride daily for one week, while the other received potassium citrate. Then, following a one week break, the treatment groups were crossed over and received the opposite treatment for an additional week. While taking potassium chloride, volunteers had an average blood pressure of 140/88, and while on potassium citrate, it averaged at 138/88. The difference between the effects of the two types of potassium was not significant, meaning each had similarly beneficial effects on hypertension.
“These results support other evidence for an increase in potassium intake and indicate that potassium does not need to be given in the form of chloride to lower blood pressure,” write the researchers in their report. “Increasing the consumption of food high in potassium is likely to have the same effect on blood pressure as potassium chloride.”
Rather than investing in a new dietary supplement, lowering your blood pressure may be as easy as watching what you eat. Foods high in potassium citrate include bananas, citrus fruit, dried apricots, fish (especially salmon, flounder, and tuna), green leafy vegetables, legumes, melons, potatoes, poultry, tomatoes, whole-grain cereals, and yogurt. So stock up on potassium-rich foods to help push your blood pressure down. But, before increasing your intake of potassium, check with your doctor. Some people — for example, those with kidney disease — may need to avoid both potassium and salt.

But why potassium helps to lower blood pressure?

Potassium is a chemical whichs helps to lower blood pressure by balancing out the negative effects of salt.
Your kidneys help to control your blood pressure by controlling the amount of fluid stored in your body. The more fluid, the higher your blood pressure.
Your kidneys do this by filtering your blood and sucking out any extra fluid, which it then stores in your bladder as urine. This process uses a delicate balance of sodium and potassium to pull the water across a wall of cells from the bloodstream into a collecting channel that leads to the bladder.
Eating salt raises the amount of sodium in your bloodstream and wrecks the delicate balance, reducing the ability of your kidneys to remove the water. By eating more fruit and vegetables, you will increase your potassium levels and help to restore the delicate balance. This will help your kidneys to work more efficiently - and help to lower your blood pressure to a healthy level.
However, it is possible to have too much of a good thing. To make sure that you don't overdose on potassium, it is best to get your daily potassium from natural sources and avoid taking supplements.