Fat Tissue Acts Like Capacitance

Batteries, as everyone knows, provide the power for most of the electrical gadgets that people use everyday. Batteries provide energy to a circuit by harnessing a slowly occurring chemical reaction.

Capacitors are equally important in electronics, but are less well-known outside the field. Capacitors are often used to “bypass” a power supply by providing energy faster than a battery can. Since batteries get power from a chemical reaction, they may not be able to respond fast enough if power requirements change quickly (for example when the transistors in a microcontroller switch states). To deal with the slowness of the battery, capacitors are charged from the battery and can be discharged when fast power is needed. One of the impacts of this is that capacitors get slightly discharged and recharged very often.

Until reading GCBC, I had always assumed that fat cells act more like a battery than a capacitor. It turns out that this isn’t the case. Fat cells do store energy in the form of fat (triglycerides), but they also release it fairly often. Fatty acids are constantly moving into and out of fat cells depending on how much energy is needed by the body. Fat cells will take in free fatty acids and tri-glycerides from the blood when blood sugar is high, and release fatty acids into the blood when blood sugar is low. This allows them to buffer energy levels from food.

According to GCBC, the flow of fatty-acids into and out of fat cells is governed by a molecule called glycerol phosphate. When glucose is metabolized in a cell, glycerol phosphate is produced. The glycerol phosphate is then released into the bloodstream, where it can be taken in by fat cells. The more glycerol phosphate in a fat cell, the fewer fatty acids the fat cell releases into the bloodstream.

Right after someone eats a meal containing carbohydrates, blood sugar rises. As the blood sugar is metabolized, glycerol phosphate is produced that causes fat cells to hold onto more of their fatty acids. This is good, because glucose is providing fuel for the body and fat isn’t needed for fuel. After a while, much of the glucose has been metabolized and glycerol phosphate levels fall. The fat cells then start releasing fatty-acids for the other cells in the body to use as fuel. That allows people to survive for long periods between eating.

Fat cells act like capacitors, continually storing up and releasing energy (in the form of fatty acids). It’s the metabolism of glucose, through glycerol phosphate, that manages this storage and release of energy.