Fat oxidation in the strict sense is a process in which two oxygen atoms bind in the (unsaturated) fatty acid chain at the double bond site (where two hydrogens are absent). The oxygen comes from e.g. from air (O2 molecule), or from another so-called oxygen radical. Subsequently, the chain at this point may split. More specifically, it is lipoperoxidation.
Fat oxidation may occur:
- in food before consumption – substances (aldehydes, ketones) are produced that have undesirable properties for health (fat becomes stale, rancid)
- directly in the body – as a natural process (eg beta-oxidation in energy release and the like) or an unwanted process (eg cell membrane breakdown by lipoperoxidation) – in the case of predominance of free radicals
The process was originally discovered and described on oxygen (hence “oxidation”). The term oxidation as such is in fact broader:
- it is simply an electron removal (on the other side, reduction is the addition of an electron, thus reducing the charge – hence the term “reduction”)
- not only fats may be oxidized but also other substances (in our case organic substances in the body, eg DNA, proteins etc.)
- the radicals exist not only on the oxygen basis, but also nitrogen basis, or organic radicals (these ones are the result of the oxidation of organic matter in the body)
The radical is characterized by the fact that it has an unpaired electron. This unstable state the radical is trying to change, and therefore it is very prone to chemical reactions. As far as it is still in this state, it is referred to as the free radical (FR). Once it succeeds and reacts, the electron is missing the other side and an even more dangerous radical can appear. This way a chain reaction can arise. In the case of excessive amounts of radicals, so-called oxidative stress arises, which can cause various problems and diseases.
Apart from the fact that free radicals are normally formed in the body, they are also produced essentially by all standard civilization “evils”, such as UV-radiation, X-ray, smog, radioactivity, toxic substances in the diet, pesticides, trans fats, and of course smoking, drugs, alcoholism.
The body is protected from the prevalence of free radicals by its own 3-stage mechanisms (FR inhibition, FR removal, tissue repair). Another helper is the so-called antioxidants (AO), which are substances that can bind free radicals and thereby stop the chain reaction and neutralize the radical.
As (isolated) antioxidants, particularly known are:
- vitamin C
- vitamin E
- β-carotene
- selenium
Better than taking isolated antioxidants is to consume them in (plant) diet. You can find them in so called phytochemicals – polyphenols, flavonoids, phytosterols, etc. Best plant antioxidants are especially:
- fresh fruits and vegetables (especially dark berries such as blackberries, raspberries, pomegranate, blackcurrants, red grapes, blueberries – relevant substances called flavonoids also work in plants as UV protection, hence dark berries), citrus fruits, onions, garlic, ginger, etc.
- red wine, green tea, dark chocolate, coffee
- nuts, seeds, mushrooms
- herbs, spices (turmeric)
- legumes, cereals
However, the prevalence of antioxidants is also not desirable, and the body needs a balance between FR and AO.