How potassium makes us think
How potassium makes us think
Potassium might be one of the most under-appreciated minerals in the body, because together with sodium it regulates the transmission of neural impulses in the brain and throughout the body. Neural transmission is what gives us the ability to think, to direct the movement of our muscles, and to regulate homeostasis (all the necessary functions of life). Let’s see how potassium works in a neuron, and how potassium plays a central role in sending and receiving electrical signals throughout the body.1
Before we begin, let’s review electricity for a moment. Electricity is like love; opposites attract. Something with a positive charge (a proton) will attract something with a negative charge (an electron). You can see this phenomenon when you rub a rubber balloon against your hair. The mechanical rubbing action steals negatively charged electrons from your hair and transfers them to the rubber of the balloon. When you pull the balloon away from your head, your positively charged hair is attracted to the now negatively charged balloon, and as a result your hair stands on end!2
Now, what does this all have to do with potassium and nerve impulses and thinking?! Read on.
A neuron, or nervous system cell, is similar to all the cells in our body, except that they tend to be longer in length. This makes sense, since their duty is to transmit messages, say, from the foot to the brain when you step on a nail. Those nerve impulses are electrical in nature, as we’ll soon find out.
Like all cells, neurons have cell membranes that separate the cell’s inner and outer environments. This is important, because without an enclosed space, a neuron would not be able to function as a unit and send signals. The magic of potassium comes into sharp focus once we look a little closer at the specialized cell membrane of a neuron.
Buried within each neuron’s cell membrane are tiny protein pumps whose job it is to escort sodium cations (Na+) and potassium cations (K+) back and forth across the cell membrane. Sodium gets pumped out of the cell, while potassium gets pumped in. These little guys work constantly, using the energy you ingest as food to do their job.
These small machines don’t pump sodium and potassium in equal amounts, however; for every three Na+ they pump out, only two K+ are pumped in. As a result, potassium accumulates in the cell while sodium accumulates outside the cell. However, electrically, there is a mismatch between total charge inside and outside the cell. Because three positive charges exit the cell for every two that enter, an imbalance is created on either side of the cell membrane.
We call this imbalance a negative electrical potential. The imbalance is considered negative because with respect to its surroundings, the cell’s interior has a negative charge. It’s called a potential because the ions on either side of the cell membrane have the potential to move closer to each other, if only they weren’t separated by the membrane.
Here’s where things get interesting. When we think a thought (send a signal from the brain) or step on a nail (receive a pain signal to the brain), other membrane proteins open up and provide those separated Na+ and K+ a way to cross the membrane in the direction of their gradients, and to equalize the negative electrical potential. In the region of the cell that responds to stepping on the nail, the cell becomes electrically positive as Na+ rushes in and K+ rushes out of the cell. Then, just like neighbors who see green grass on the far side of their fence, nearby sections of the cell membrane open up to allow an electrical equalization to happen there. The cell experiences a sweeping depolarization that sends an electrical signal down the length of the cell.
Once the neural impulse is sent, the Na+/K+ pumps reset the cell to its resting membrane potential so that the neuron can respond to another thought or action. This process happens nearly instantaneously across each of our neurons constantly throughout the day and night, and requires potassium to make it happen.3
Potassium also plays a central role in the autorhythmic cells that initiate cardiac muscle tissue contraction. Hypokalemia, or a potassium deficiency, is a serious condition that can disrupt the cardiac cell’s membrane potential, causing heart arrhythmia.1 Potassium chloride (KCl) is a solution that can replenish potassium amounts when taken in low doses like those found in Vivioptal Vitamins.
Rather than being simply a beneficial mineral found in bananas and various meats, potassium is a basic requirement of life and forms the foundation of thought, muscle movement, and blood circulation. You wouldn’t go too long without replacing your potassium stores, since it is one of electrolytes lost when we sweat. For that reason, it’s not a bad idea to keep a few extra bananas lying around, just in case you need a quick brain boost. Or, take a quick multivitamin supplement to refuel your body’s potassium sources!
1) Insel P, Turner RE, Ross D. Discovering Nutrition. 3rd ed. Jones and Bartlett, Sudbury Massachusetts. pp 412-413.
2) Walker, JS. Physics. Vol. 2, 4th ed. Addison-Wesley, Pearson Ed. Inc. p.655
3) Silverthron, DU. Human Physiology – An Integrated Approach. 5th ed. Pearson Ed. Inc. p. 164-171.