Role of anti-oxidants in nutrition and health – Why Antioxidants are needed for Health

The role of antioxidants in health has been buttressed by a number of epidemiologic studies that have showcased the part played by food – or lack thereof – in development and progression of chronic diseases. With many antioxidants having been found vegetables and fruits (as reviewed earlier), Bazzano (2006), in a research editorial, presents a case  of why these two types of food should form a constant diet in the population for better health outcomes to accrue. Through a review of literature the editorial presents a link between consumption of fruits and prevention of conditions such as coronary heart disease (CHD), Stroke, high blood pressure, obesity and type II diabetes (Bazzano, 2006). Some of these diseases (e.g. CHD) could be promoted by oxidation hence the protective role of fruits and vegetables suggested could be brought about by their high antioxidant contents.

In a different study, Yang (2009) evaluates the composition of Brazilian nuts and the health benefits associated with their intake. Through a review of literature the study evaluates the macronutrients found in nuts noting that various types of lipids – polyunsaturated fatty acids (PUFA) and monosaturated fatty acids (MUFA) –  found in the nuts to beneficial health units in such diseases as coronary illnesses (Yang, 2009). Similarly the nuts have a high mineral composition with high Selenium content associated with various enzymatic process such as those in glutathione-mediated inactivation of free radicals; and high phytochemical composition (phenolics, tocopherols, and phytosterols) that have been associated with a reduced risk of atherosclerosis and cancer out of their antioxidant and antiproliferative properties (Yang, 2009).

Yet another study evaluates health benefits of berry flavonoids, a group of antioxidant compounds, with respect to menopausal women (Huntley, 2009). Through a review of literature the paper presents the flavonoids subclasses (flavanols, flavonols and anthocyanins) present in polyphenols found in many fruits and nuts which have beneficial health outcomes (Huntley, 2009). Since menopausal women have increased risk of diseases such as cancer and heart diseases due to reduced hormonal levels, the review evaluated the studies that have researched the effect of flavonoids in such subjects with respect to suggested “cardiovascular benefits, cancer prevention and cognitive improvement” (Huntley, 2009, p.297). After this review the study concluded that such suggested health benefits of antioxidants on menopausal women to hold especially with regard to antioxidants derived from berries.

Various other studies have elucidated the link between consumption of beverages such as tea and cancer prevention and suggested a significant involvement of the antioxidants found in these beverages in such a role (e.g. Weisburger, 1997). Such studies have buttressed the role of antioxidants in preventing diseases such as cardiovascular disorders, cancer and atherosclerosis thus bearing some implications for the role of nutrition in combating illnesses mediated by ROS that have become more common in modern society.

Free Radicals and their Prevention

Free radicals are some of reactive chemical substances that are generated in body processes such as those of the immune system to confer protection against microbes. These species have at least one free-floating electron making them highly unstable and thus highly reactive (Bagchi & Puri, 1998). Though free radicals could arise in many atoms, most of those that occur in the human body are involve oxygen and include superoxide radical (O.2), hydroxyl radical (OH.), lipid peroxyl radical (LOO.) and nitric oxide radical – NO. (Bagchi & Puri, 1998). In the body these radicals can arise either from enzymatic reactions in such processes as the respiratory and cytochrome P450 (cytP450) mediated reactions; or from non-enzymatic oxygen-mediated or ionizing radiations- mediated reactions (Bagchi & Puri, 1998). If left inactivated, free radicals can initiate damaging reactions by bonding with cellular components (e.g. proteins, lipids and nucleic acids) thus bringing adverse health outcomes such as development of cancer (Bagchi & Puri, 1998). Some of the free radical reactions have for instance been linked to immune reactions that play a significant role in the pathogenesis of alcoholic liver disease (Albano, 2002).

To counteract free radical and other reactive species’ effects the body possesses various mechanisms including enzymes (e.g. glutathione peroxidases and catalase) that catalyze reactions reducing the level of the harmful species in the tissues (Bagchi & Puri, 1998). Various nutritional components such as minerals are needed to promote functions of these enzymes thus implying a significant role of nutrition (Yang, 2009; Bagchi & Puri, 1998). Once such primary defense mechanisms are depleted by high levels of ROS then nutrition also bears a role in provision of a secondary defense mechanism – antioxidants. Antioxidants such as phenolic compounds found in many foods could inactivate the reactive compounds by forming complexes thus preventing the ROS’s reaction with cellular components (Bagchi & Puri, 1998; also reviewed earlier). Some of the compounds that have been shown to exhibit antioxidant properties include Vitamin E, Vitamin C, and ß-carotene (Bagchi & Puri, 1998). These compounds occur in many natural foods (e.g. vegetables, fruits and fish) and thus consumption of such foods could present better health outcomes for the population.

References

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