Parametre identity: The tocopherol fraction of olive oil comprises four tocopherols: α–tocopherol (trimethyltocol), β-tocopherol and γ–tocopherol (dimethyltocols), and δ–tocopherol (monomethyltocol).
Reason: Tocopherols exist naturally in olive oil and have both an antioxidant and vitamin value. They work as an antioxidant protecting the olive oil from going rancid when it is attacked by atmospheric oxygen and the rays of the sun. The vitamin value they offer is high, given that α–tocopherol (vitamin E) predominates.
Points of information: An olive oil with high tocopherol content has a high degree of protection and therefore a longer life, while at the same time consumption of such oil protects human cells from oxidative stress.
Useful things to know about tocopherols
The essential points about olive oil tocopherols can be summarised as follows:
- α–Tocopherol (vitamin E) is the principal tocopherol in olive oil and is of most interest from the dietary point of view as it offers the greatest biological value.
- 90-95% of olive oil tocopherols are type α, which is the most active protective agent against autoxidation.
- Although olive oil has a lower tocopherol content that other foods and edible oils, it has a higher vitamin value because the tocopherols present in olive oil are type α, compared to other seed oils, in which the tocopherols are principally types β and γ.
- Extra virgin olive oil has a tocopherol content of 130-330 ppm (mg/kg) when it is fresh and of good quality. Storage of the oil, especially under bad conditions, leads to a drop in tocopherol content. Refined and lower quality olive oils have almost zero content.
- Both the vitamin value of tocopherols and their antioxidant activity is reduced from type α to type δ if the oil is stored for long periods under the wrong conditions.
The biological action of α–tocopherol
As one can easily comprehend from the above, when we speak of tocopherols in olive oil, we are essentially speaking of α–tocopherol. Here we concentrate on the latter in order to look at its multifaceted biological action and note how special indeed is an olive oil that has a high α–tocopherol content.
The biological action of α–tocopherol and the consequences of a vitamin E deficiency are set out in brief below:
- α–Tocopherol, or vitamin E, is a one of the oil-soluble vitamins and has a strong antioxidant action on human cells and on foods, particularly during frying or freezing, which create conditions favouring the phenomenon of rancidity. Olive oil is thus not affected as cell membranes are protected against rancidity.
- It binds the free radicals which form in the course of metabolism and which are responsible, at least in part, for the aging of cells.
- It is necessary for the creation of red blood cells and muscle cells.
- It contributes to the body’s endurance and absorption of oxygen by the cells.
- It is used especially by the brain, the nervous system and the lungs, wherever, that is, there is a high concentration of polyunsaturated fatty acids (PUFAs), preventing the reactions of the chemical compounds which oxidize the fatty acids and stop the normal function of the cells, which causes tissue aging.
- One molecule of α–tocopherol protects 20,000 molecules of unsaturated fatty acids from going rancid.
- The intervention of α–tocopherol means that peroxides and hydroperoxides are not formed, particularly 5,6alpha–epoxycholesterol, which is a carcinogen.
- Studies have shown that individuals with low vitamin E in their blood are 50% more susceptible to the development of all types of cancer.
- Moreover, sufficiency in vitamin E:
- Strengthens the immune system: the administration of α–tocopherol in the form of a daily supplement of 400 or 800 IU to individuals over sixty years of age improved their immune system considerably
- Reduces the risk of bladder cancer by 50%
- Reduces the risk of Alzheimer’s disease by 67%
- With respect to coronary heart disease, administration of α–tocopherol in the form of a daily supplement of 400 or 800 IU may reduce non-lethal cardiac episodes by averting the oxidation of the lipids, thus changing the size of the coronary atheromatous plaque
- With respect to Parkinson’s disease, the administration of high doses of vitamin E may slow the development of the disease and reduce the severity of other neurological disorders.
- It protects collagen tissues from the destructive action of free radicals which leads to wrinkles.
- It hydrates the skin and strengthens hair and nails.
- It supports the production of sexual hormones.
- It protects from the damage caused by UV rays, limiting the potential for sunburn.
- It regulates the synthesis of DNA.
- Vitamin E deficiency in humans is rare, occurring in the case of:
Persons who have a problem with absorbing oils, e.g., with pancreatitis, steatorrhea (excessive excretion of fat with the faeces);
Extensive bowel resection;
Children with kwashiorkor;
Chronic exocrine pancreas insufficiency;
Chronic hepatobiliary disease.
- In the case of α–tocopherol deficiency, there is an accumulation of peroxides, causing damage to membrane integrity and increasing membrane permeability, allowing lysosomes to escape which in turn release destructive enzymes. The accumulation of peroxides may, under certain conditions at least, also trigger the formation of tumours.