Before we can understand why Glutathione(GSH) is important for the body, we should first explain about Reactive Oxygen Species(ROS).
When most people think of oxygen (O2), they imagine it as a vital molecule that we get through breathing. It is true; we cannot live without oxygen. However sometimes the oxygen molecules in our body can accept free electrons and become negatively charged. When this happens, these oxygen molecules with extra electrons become highly reactive and unstable, thus the name, Reactive Oxygen Species (ROS).
Reactive Oxygen Species are mostly formed from the breakdown of sugar into the energy our body needs but can also be formed by some other processes.
In one of the last processes of converting sugar into energy, electrons are transferred along the Electron Transport Chain in the Mitochondria. However, in normal cells, about 1% of the time these electrons can leak out and form Reactive Oxygen Species. Electron leakage is higher in aged cells or unhealthy cells.
The individual parts of DNA and RNA, Nucleotides, when degraded by an enzyme in the liver produce a Reactive Oxygen Species as a byproduct.
ROS as a weapon:
When immune cells find invading bacteria in the body, they consume the bacteria and create ROS to kill that bacteria. However, ROS production can sometimes get out of hand. When this happens, the immune cells can damage our healthy cells with ROS rather than its intended target.
Light Produced ROS:
Many people know that ultraviolet light can cause damage to your DNA. It has been recently shown that ionizing radiation from ultraviolet A (UVA) and even visible light can produce Reactive Oxygen Species in your skin.
Types of ROS
This is what a normal molecule of Oxygen looks like; each oxygen atom has 6 electrons in its outermost shell indicated by those green dots.
When oxygen picks up an extra electron, indicated in red, it forms a superoxide. It is a free radical and is a toxic molecule within the cell.
If a Superoxide happens to pick up another electron, it forms a Peroxide. This molecule is unstable and thus very reactive. However, because of its high negative charge, it cannot go far in the body.
Perhaps you have heard of Hydrogen Peroxide before. It is commonly used as a disinfectant. Hydrogen Peroxide is not a charged molecule, so it can travel further in the body than any other ROS and cause damage. Thus it can travel into the cell’s nucleus and damage your DNA.
The last ROS is Hydroxyl Radical. Hydroxyl Radical is produced by the decomposition of Peroxides, or they can be formed from UV light splitting Hydrogen Peroxide. Hydroxyl Radial is extremely reactive. They immediately steal electrons from any molecule it touches, converting that molecule into a free radical and propagating a chain reaction.
When ROS are formed in a cell, it can immediately lead to enzymes, membrane lipids, and DNA and its base pairs being damaged. Furthermore, excess ROS can create oxidative stress in the cell and can disrupt normal mechanisms of cellular signaling. ROS has been thought to cause or play critical roles in:
And many more…
Thus, as soon as Reactive Oxygen Species are formed in the body, they must be immediately removed before they can cause damage. The body has several methods of removing ROS, but perhaps the most important is Glutathione (GSH).