Polyphenols as Antioxidants

This is part of our ongoing The Best Kept Secrets to Healthy Aging spotlight. Each day, we will be posting some of the great information that’s packed into our book, The Best Kept Secrets to Healthy Aging.

Today’s topic:
Polyphenols as Antioxidants

Several polyphenols have direct antioxidant effects. Others are metabolized by bacteria in our intestines. These metabolites are absorbed into the bloodstream and they influence cell-signaling processes that lead to immune-supporting effects and free radical-scavenging effects. Polyphenols are the most abundant antioxidants in the diet. Typically, the total dietary intake of polyphenols is about 10 times higher than the intake of vitamin C and 100 times higher that the intakes of vitamin E and carotenoids. By themselves, the anthocyanins often contribute more than half of the total antioxidant activity of the diet.21

The polyphenols not only directly detoxify potentially oxidizing substances within the body, they increase the body’s inherent antioxidant defenses. For example, an important mechanism by which polyphenols enhance antioxidant defenses in the body is through stimulating the synthesis of glutathione, the major antioxidant enzyme within human cells.22 As antioxidants, polyphenols display a dual nature – directly blocking oxidation themselves and recruiting more natural defense systems into the fray.

A considerable body of scientific literature underlines the important role of combating oxidative stress in the maintenance of optimal cell, tissue, organ and body-wide healthy function. Although the complex relationships between antioxidant status and healthy aging are still poorly understood and are being studied intensively, it is clear that the polyphenolic phytonutrients protect cell constituents against oxidative damage by virtue of their powerful antioxidant potency. They also help prevent oxidation from occurring. New research findings published in Clinical Chemistry show that low-density lipoproteins (LDL) that have had resveratrol added to them by the liver are resistant to oxidation.23 Unoxidized LDL can be removed from the body safely without harm to the cardiovascular system.24

Our ability to increase our own antioxidant prowess was recently demonstrated by the results of a study published in the Journal of Nutrition.25 In this study, the greater the number of different fruits and vegetables in the diet, the more effective the mix was in improving the body’s antioxidant status. Women who ate on average 8 servings a day of a broad range of fruits and vegetables, providing an array of polyphenolic phytonutrients, increased their antioxidant status more than women who ate on average 9 servings a day of just a few fruits and vegetables. This finding reinforces the message that the more diverse and polyphenol-rich the diet, the healthier one is likely to be. It also speaks to the fact that one should consume a variety of brightly colored foods for health. After all, a variety of polyphenols are responsible for the range of beautiful, bright colors seen in fruits and vegetables.

Polyphenols can be the champions of your antioxidant defense system – and the more polyphenols you consume, the stronger your defenses.

Next Best Kept Secrets to Healthy Aging topic:
Polyphenols – More Reasons to Love Fruits and Vegetables

References:
21. Prior RL. Fruits and vegetables in the prevention of cellular oxidative damage. Am J Clin Nutr 2003;78:(Suppl.):570S-578S.
22. Moskaug JO, Carlsen H, Myhrstad MC, Blomhoff R. Polyphenols and glutathione synthesis regulation. Am J Clin Nutr 2005;81Suppl.):277S-283S.
23. Urpi-Sarda M, Zamora-Ros R, Lamuela-Raventos R, Cherubini A, Jauregui O, de la Torre R, Covas MI, Estruch R, Jaeger W, Andres- Lacueva C. HPLC-Tandem mass spectrometric method to characterize resveratrol metabolism in humans. Clin Chem 2007;53:292-299.
24. Carluccio MA, Siculella L, Ancora MA, Massaro M, Scoditti E, Storelli C, Visioli F, Distante A, De Caterina R. Olive oil and red wine antioxidant polyphenols inhibit endothelial activation: Antiatherogenic properties of Mediterranean diet phytochemicals. Arterioscler Thromb Vasc Biol 2003;23:622-629.
25. Thompson HJ, Heimendinger J, Diker A, O’Neill C, Haegele A, Meinecke B, Wolfe P, Sedlacek S, Zhu Z, Jiang W. Dietary botanical diversity affects the reduction of oxidative biomarkers in women due to high vegetable and fruit intake. J Nutr 2006;136:2207-2212.


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