Oxidative protection

Other functional parts of the cell - outer membrane with cellular receptors, or the energy factory, mitochondria - are not spared either, although the rate of damage accumulation is slower here, since it doesn't get passed on during cellular division. Not seldom, the damage is compounded by body's own inflammatory response to oxidative injury, such as the case with blood vessel inner lining. As a result of the repair to oxidative injury, the vessel walls harden and thicken, causing hypertension and cardiovascular disease.

 Ageing, disease and death are mainly the consequence of this accumulated oxidative damage throughout the body.

From the standpoint of body function, free radicals are toxins, because they cause injury to the body and its functions. Thus body's oxidative protection can be looked at as an inherent part of the detox system. Not only that it protects rest of the body from oxidation created by the detoxication process,

it also protects the integrity of the detox system itself.

Body's detox function is directly dependant on the available energy. For instance, the three major transferase enzymes, UDPGT (UDP Glucuronyl Transferase), PAPS and glutathione, all require ATP (adenosine triphosphate, the cellular energy storage/transport molecule) unit for each single reaction they mediate. If mitochondria, where cellular energy is produced, gets damaged due to inadequate oxidative protection, it will inevitably take detoxification efficiency - and viability of the entire cell - to a lower level.

Accumulation of free radicals will also damage detox enzymes, resulting in less efficient detoxification, which in turn will increase the rate of formation of reactive compounds, in addition to the toxic build up. The vicious circle of oxidative damage ensues.

Another important source of free radicals is body's purposeful production and use of them. For instance, the immune system synthesizes and uses hydrogen peroxide in macrophages and white blood cells, like neutrophils, to destroy bacteria; it is also synthesized and used by the thyroid gland in hormonal production. Oxidative activity and, inevitably, injury, is

inseparable part of the inflammatory process,

with which the body attempts to block greater injury, or threat of, to the body and repair the damage. This is what makes long, often hidden infections so dangerous, especially when combined with inadequate anti-oxidative protection.

Put simply, if your body doesn't get adequate protection from oxidation, it will be injured, and your health will suffer. As expected, considering the seriousness of the threat, compounds that body can use against oxidative damage - so called antioxidants - are many, and have to come in a continuous supply. They are either supplied by foods, as nutrients, or are synthesized by the body.

Among antioxidant nutrients, major role belongs to vitamins C and E. The former is water soluble, protecting blood, cerebrospinal and other fluids; the latter is lipid-soluble, protecting lipids in the cellular membrane. Their synergistic effect provides especially powerful protection at the membrane surface. Beta-carotene, fat-soluble precursor of vitamin A, also acts as antioxidant, but not as powerful as vitamins C and E.

Certain minerals, like selenium and zinc, are considered to be antioxidants, because they are needed by antioxidant enzymes synthesized by the body (more on that in a bit).

There is a number of less researched plant antioxidants, some of them more, or much more potent than vitamins C and E. The most significant belong to the broad class of compounds defined by their color, called flavonoids. Such are proanthocyanins, (also proanthocyanidins, or procyanidins, colorless polyphenols that change to red in autumn leaves) like grape seed extract and pine bark extract, water-soluble antioxidants particularly effective in protecting blood vessels. Another potent antioxidant group are red-to-purple plant pigments anthocyanins (also, anthocyanidins), found in berries, cherries, eggplant, black ("forbidden") rice, blue grapes, red cabbage, black legumes, novel plants like purple broccoli and corn, blue potato, and in a variety of other plants, in smaller quantities.

These antioxidants belong to over 8,000 phenolic compounds found, thus far, in plants. The main function of these plant metabolites is anti-oxidative and/or anti-microbial protection. The beneficial effect of these compounds extends to us, humans, with many of them being not only strengthening our antioxidative protection, but also - and mainly due to that - being antimutagenic and anticarcinogenic.

The level of antioxidative protection of plant foods is measured by their Oxygen Radical Absorbance Capacity (ORAC). The higher number, the better antioxidative protection. Following table lists the top 62 antioxidant plant foods, according to the USDA (full USDA ORAC report for 277 foods).

FOODS WITH HIGHEST ANTIOXIDATIVE CAPACITY: Phenolic compounds provide potent antioxidant protection to plants. They are either hydrophilic (water-soluble) or lipophilic (fat-soluble). Their content is highest in row and whole foods (for instance, cooked beans retain only about 1/10 of their antioxidative capacity when raw; likewise, removing skin from an apple reduces its antioxidative capacity by up to 1/3).

Body's own production of antioxidants is not less extensive. At the very top is sulfur-containing lipoic acid, which is not only effective against more radical forms than any other antioxidant, but also can recycle other antioxidants.

The next is glutathione, tripeptide consisting from amino acids glycine, cysteine and glutamic acid, which is also found in a variety of foods, but not in sufficient quantities (also fairly easy to destroy).

The key cellular antioxidants are superoxide dismutase (SOD), catalase and glutathione peroxidase enzymes. The SOD variety predominantly active in the mitochondria uses manganese, while SOD variety mainly found in the cellular fluid (cytosol) contains copper and zinc.

Catalase, an iron-containing enzyme, helps neutralize hydrogen peroxide, although it is less important than selenium-containing glutathione peroxidase.

Sulfur-containing amino acids like cysteine and methionine, as well as small antioxidant molecules like uric acid and copper-containing ceruloplasmin assist vitamin C in protecting the blood and other aqueous regions of the body from uncontrolled radical damage.

This barely scratches the surface of incredible complexity of the detox system. Also, we can see why is nutritional balance the key for proper functioning of the detox system, and the body as a whole. For instance, we need sufficient levels of copper for the main cellular radical quencher, SOD, and iron to support the Phase I detox cycle. However, excessive levels of these two metals will likely increase the level of copper and iron ions in the body, and with it the level of some of the most reactive oxidizers, like hydroxyl and peroxyl radicals, capable of inflicting serious damage to your tissues and organs longer-term, especially if you are low on antioxidants.