Nutrition Vitamins and minerals

Antioxidants: what they are and what they do

Antioxidants: what they are and what they do

by in Nutrition - Vitamins and minerals

last updated: September 26, 2017

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The function of antioxidants is to prevent or control oxidation processes; hence the prefix anti, that is, "against" the term. Oxidation is the process of combustion of oxygen in cells for the production of energy and the consequent release of substances known as free radicals.

The use of antioxidant supplements has been widespread among consumers and healthcare professionals. Researchers are collecting daily evidence on the possibility of preventing or improving the course of many pathologies due to the use of antioxidants, whether they are directly acquired through diet or insured through dietary supplements. The function of antioxidants is to prevent or control oxidation processes; hence the prefix anti, that is, "against" the term. Oxidation is 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 extremely responsive unstable molecules that can damage cell DNA as well as various tissues. According to researchers' estimates, free radicals affect cell DNA with a frequency between 75,000 and 100,000 times a day. The free radical molecules are characterised by an electron discharge (an atomic particle equipped with electric charge) and therefore tend to combine with other molecules to reintegrate the missing electron. This process produces further free radicals.

The oxidative process

A good example of oxidative process is observed in apples when cut: within a short period of time, the pulp darkens. This is because the atmospheric oxygen reacts chemically with the exposed portion of the apple. If you cut an apple and immediately sprinkle lemon juice on the pulp, you would notice that dark coloration (oxidation) would appear much later. This protective effect is attributable to antioxidants, more specifically to vitamin C and bioflavonoids found in lemon juice. Within the human body, similar reactions continue to occur; for example, antioxidants prevent cholesterol oxidation. The researchers noted that cholesterol actually becomes harmful only when it suffers oxidation, thus favouring the process of atherosclerosis. In subjects following a particularly rich diet of fruits and vegetables, which represent the best natural source of antioxidants, the risk of cardiovascular disease is reduced, and the same is true for a variety of cancers and other chronic disorders.

Sources of free radicals

In addition to free radicals derived from the vital processes of energy production within cells, humans are also exposed to various factors that increase the number of free radicals. Ionising radiations of sunlight, X-rays and several other sources are the most common factors; excess exposure can in fact cause skin cancers, wrinkles and cataracts. Industrial pollution also contributes to this load by adding toxic metals such as arsenic, mercury and others, apart from industrial fumes and numerous other toxins. It should also be considered that many pharmaceutical products create free radicals. In addition, the body of people suffering from chronic diseases such as diabetes produces more free radicals than the healthy individual, while in athletes the free radical formation is quantitatively superior because they are secondary products of exercise. Finally, smoking, alcohol, fried foods and fat-rich diets are all well known sources of toxic free radicals.

Antioxidant enzymes

The human body has its own antioxidant system that includes specific enzymes such as catalase, superoxide dismutase (SOD) and glutathione peroxidase. Minerals such as selenium, manganese, zinc and copper are needed to ensure efficient functioning of enzymatic complexes.

Common antioxidants

Since North America's typical diet is lacking in antioxidant vegetable foods, it is important for the person to supplement their intake by using additional antioxidant nutrients. Among the most common antioxidant agents are vitamins A, C and E, as well as selenium, glutathione, coenzyme Q10 and betacarotene. Further antioxidants are lutein, lycopene, and other carotenoids. Grape seed extract, N-acetylcysteine, alpha-lipoic acid and tocotrienols are also excellent antioxidant agents. Phytonutrients present in some plant species such as green tea, turmeric, ginkgo biloba and marigold have among the most powerful antioxidant properties ever discovered. Each antioxidant plays a primary role in neutralising free radicals and optimising immune defences. And these are just a few examples of antioxidants available in foods and supplements.

Analysis of the state of the antioxidants

There are several ways to check the state of the body's antioxidant system. One of these is to use a blood test that measures the values of the major antioxidant agents present in the blood stream. Another method is a blood or urine test to detect the body's oxidative stress level in general; This method provides an assessment of the state of oxidative stress and of systematic antioxidant reserves. Finally, a computer technology has been developed recently that uses a low wavelength blue laser to scan the palm of your hands and measure the levels of antioxidants associated with carotenoids.

Bibliographic references: dietary supplements

Anderson, R. A., «Chromium as an essential nutrient for humans», Regulatory Toxicology and Pharmacology, 26 (1 Pt 2),
S35-41, 1997Bower, 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.
146-155Fairfield, K. M., Fletcher R. H., «Vitamins for chronic disease prevention in adults: Scientific review», Journal of the American Medical Association, n. 287, 2002, pp.
3116-3129Ferslew, 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.
84-88Recker, 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. 93-95Wesler
, M. S., Shapiro, S., Mitchell, A., «Preconceptual folic acid exposure and risk of occurrent neural tube defects», Journal of the American Medical Association, n. 269, 1993, pp. 1257-1261

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