Oxygen is key for our lives since it is the fuel for cells in order to generate energy. At the same time, it is a powerful oxidant, since it participates in chemical reaction which causes cellular oxidation.
A small percentage of the oxygen that we breathe produces free radicals. Free radicals are unstable atoms, molecules or ions with an unpaired electron. They circulate throughout the body trying to steal an electron from stable molecules in order to reach electrochemical stability. During this process, free radicals oxidize new molecules, turning them into free radicals. Thus, a chain reaction takes place, destroying or deteriorating cells.
This continuous "electron theft" provokes inflammation that causes disease and aging.
Our lifestyle and the surrounding environment generate in our body more free radicals to what is physiologically common.
Reactive Oxygen Species (ROS) are free radicals containing oxygen (•O2-, H2O2, •OH y ¹O2). They are produced in the body naturally when we consume the oxygen we breathe. They are beneficial because they coordinate cell activity, they regulate the immune system and they participate in the antibacterial defense. However, they can become extremely harmful when they exceed the antioxidant capacity of the body.
Excess of ROS may cause damage to cellular components indiscriminately, including lipids, proteins and DNA, thus provoking necrosis and cell death. This is the so-called oxidative stress, as a result of a trade-off between body antioxidants and free radicals.
Persistent oxidative stress may cause severe damage and it is one of the sources of the majority of lifestyle related diseases as well as of aging.
Oxidative stress may be also caused by several factors such as inflammation, intense exercise, heart or brain attack, interruption of blood flow and organ transplantation among others, that is under ischemic, inflammation or pathological conditions.
There are protective mechanisms against oxidative damage which counteract the effect of free radicals. They are known as antioxidant action mechanisms. Antioxidants are substances capable of donating electrons to free radicals, thus neutralizing them.
However, as we get old, the antioxidant function of our cells is not enough to eliminate oxidative damage, resulting in diseases.
Aging is evidenced differently in our body. Dehydration is a symptom of cellular aging caused by oxidation and it progressively increases during our lives.
At maturity, our body has lost 50% of water.
Oxidative stress has been linked to various diseases such as some types of cancer, cardiovascular disease, obesity, diabetes, Alzheimer's disease, rheumatologic diseases, eye diseases and skin allergies amongst others.
Many of these diseases may be prevented with an apropriate balance between oxidative stress and antioxidant levels.