It’s well known that our risk of developing persistent health issues increases as we age. The reasons behind this are incredibly complex, but one of the most widely accepted explanations is called the “free radical theory of aging”. First conceived in 1956, it is one of the most thoroughly researched theories known and, although not fully proven, it is the best theory so far. It is supported by conclusive evidence that oxidative stress is intimately involved in aging.
Free radicals are uncharged molecules or atoms with unpaired electrons in their outermost valence shell. They are unstable and highly reactive which can react deleteriously with important molecules of the living cell. Free radicals are by-products of chemical processes such as oxidation and all oxidation processes occur via a free radical mechanism. The body’s ability to release energy from the food we eat and the oxygen we breathe occurs by a process called oxidative phosphorylation. This happens in the mitochondria inside our cells, which are the powerhouses that drive our metabolism and bodily functions.
A small amount of free radicals are essential for our cellular function and are utilized by our immune system to fight off infections. However, they need to be kept to a low level, otherwise they will damage our own cells by causing oxidative stress. During oxidative stress, the free radicals run unchecked damaging all cellular components including nucleic acids (e.g. DNA), proteins and lipids. It is for this reason that every cell must have its own supply of antioxidants.
Antioxidants are compounds when present at low concentrations compared with those of an oxidizable molecule, significantly delay or prevent oxidation or damage of those molecules. When free radicals are generated in our bodies many antioxidants act in defending us from oxidative damage. Being found in the highest concentration of all of the naturally found antioxidants in our body, glutathione is critical in inhibiting oxidation by free radicals.
In many poisonings (e.g. heavy metals and acetaminophen overdose), the glutathione in our cells (particularly those in the liver) is rapidly (acutely) depleted. This occurs if our cellular capacity to produce glutathione is overrun by the onslaught of free radicals generated by the poison or overdose.
During ageing and in many chronic conditions, the affected cells have lost the ability to make enough glutathione to manage the free radicals to a safe level. This leads to progressively worsening damage and ultimately the loss of physiological function, where we become ill and show the symptoms.