The function of antioxidants
The use of antioxidant-based supplements has spread widely among consumers and healthcare professionals. Researchers collect further evidence every day on the possibility of preventing or improving the course of numerous diseases thanks to the use of antioxidants, whether they are directly acquired through diet or ensured through food supplements.
The function of antioxidants is to prevent or control oxidation processes; hence the prefix anti, that is "against" of the term. Oxidation refers to the process of combustion of oxygen in cells for the production of energy and the consequent release of substances known as free radicals. Free radicals are highly reactive unstable molecules that can damage cellular DNA as well as various tissues.
According to researchers' estimates, free radicals affect the DNA of cells between 75,000 and 100,000 times a day. Free radical molecules are characterized by an unpaired electron (an atomic particle with an electric charge) and, therefore, tend to combine with other molecules to replenish the missing electron. This process actually produces more free radicals.
The phenomenon of oxidation
A good example of an oxidative process can be seen in apples when they are cut: within a short period of time, the pulp darkens. This happens because atmospheric oxygen chemically reacts with the exposed portion of the apple. If you cut an apple and immediately sprinkle lemon juice on the pulp, you would notice that the dark color (oxidation) would appear much later.
This protective effect is attributable to antioxidants, more specifically to vitamin C and bioflavonoids, present in lemon juice. Within the human organism similar reactions are continually occurring; for example, antioxidants prevent the oxidation of cholesterol. Researchers noted that cholesterol only becomes actually harmful when it undergoes oxidation, thereby promoting the atherosclerosis process.
In subjects who follow a diet particularly rich in fruit and vegetables, which represent the best natural source of antioxidants, the risk of cardiovascular diseases is reduced.
Other sources of free radicals
In addition to free radicals deriving from the vital processes of energy production within cells, humans are also exposed to various factors that increase the number of free radicals. Ionizing radiation from sunlight, X-rays and several other sources are the most common factors; excessive exposure can in fact cause skin cancers, wrinkles and cataracts. Industrial pollution also contributes to burdening this load by adding toxic metals, such as arsenic, mercury and others, industrial fumes and numerous other toxins. It is also necessary to consider that many pharmaceutical products create free radicals. Furthermore, the organism of people suffering from chronic diseases, such as diabetes, produces a greater number of free radicals than the healthy individual, while in athletes the formation of free radicals is quantitatively higher since they are secondary products of physical exercise. Finally, smoking, alcohol, fried foods, and high-fat diets are all notorious sources of toxic free radicals.
The role of the human body
The human body has its own antioxidant system which includes particular enzymes, such as catalase, superoxide dismutase (SOD) and glutathione peroxidase. Minerals such as selenium, manganese, zinc and copper are necessary to ensure the efficient functioning of the enzyme complexes.
The best known antioxidants
Since the typical North American diet is deficient in antioxidant-rich plant foods, it is important for the person to supplement their intake by using additional nutrients. Among the most common antioxidant agents are vitamins C, A and E, as well as selenium, glutathione, coenzyme Q10 and beta-carotene. Additional antioxidants are lutein, lycopene and other carotenoids. Grape seed extract, N-acetylcysteine, alpha-lipoic acid and tocotrienols are also excellent antioxidants. The phytonutrients present in some plant species such as green tea, turmeric, ginkgo biloba and milk thistle have some of the most powerful antioxidant properties ever discovered. Each antioxidant plays a primary role in neutralizing free radicals and in optimization of the immune defenses. And these are just a few examples of antioxidants available in foods and supplements.
Know the health of the antioxidant system
There are multiple ways to check the state of the body's antioxidant system. One of these is to have a blood test that measures the values of the main antioxidant agents present in the bloodstream. Another method is represented by a blood or urine test aimed at identifying the level of oxidative stress of the organism in general; this method provides an evaluation of the state of oxidative stress and of the reserves of antioxidants at the systemic level. Finally, computer technology has recently been developed that uses a low-energy, blue-light laser to scan the palm of the hands and measure the levels of antioxidants associated with carotenoids.
Anderson, R. A., «Chromium as an essential nutrient for humans», Regulatory Toxicology and Pharmacology, 26 (1 Pt 2), S35-41, 1997
Bower, C. Stanley, F., Nicol, D., «Maternal folate status and risk for neural tube defects», Annals of the New York Academy of Sciences, n. 678, 1993, pp. 146-155
Fairfield, K. M., Fletcher R. H., «Vitamins for chronic disease prevention in adults: Scientific review», Journal of the American Medical Association, n. 287, 2002, pp. 3116-3129
Ferslew, K. E., Acuff, R. V., Daignault, E. A., Wolley, T. W., Stanton Jr., P. E., «Pharmacokinetics and bioavailability of the RRR and all racemic stereoisomers of alpha-tocopherol in humans after single oral administration», Journal of Clinical Pharmacology, n. 33 (1), 1993, pp. 84-88
Recker, R. R., Bammi, A., Barger-Lux, J., Heaney, R. P., «Calcium absorbability from milk products, an imitation milk, and calcium carbonate», American Journal of Clinical Nutrition, n. 47, 1988, pp. 93-95
Wesler, M. S., Shapiro, S., Mitchell, A., «Preconceptual folic acid exposure and risk of occurrent neural tube defects», Jounal of the American Medical Association, n.269, 1993, pp. 1257-1261