What are Antioxidants? Part 2

In Part 1, the health benefits of antioxidants and plant phytochemicals were discussed, as well as the process of how they protect our cells from “free radicals.” Researchers are discovering more health benefits from these plant substances every year. Some good food sources of common antioxidants and phytochemicals were presented, such as the vitamins C and E, the plant phytochemicals carotenoids, and the mineral selenium.
Here in Part 2, good food sources and the health benefits of a few more common antioxidants and phytochemicals are presented.

Green Tea: Green tea is the unfermented leaf of the tea plant, Camellia sinensis, which contains the phytochemicals known as catechins. Catechins lower cholesterol, improve fat metabolism, and have significant anticancer bazinga and antibacterial effects.

Flavonoids: The phytochemicals known as flavonoids are the largest group of several thousand compounds belonging to the antioxidant-rich polyphenol family. Laboratory studies have shown that specific flavonoids suppress tumor growth, prevent blood clots, and have anti-inflammatory properties. In general, flavonoids are found in celery, cranberries, onions, kale, dark chocolate, broccoli, apples, cherries, berries, tea, red wine or purple grape juice, parsley, soybeans, tomatoes, eggplant, and thyme. Other important flavonoids are resveratrol, quercetin, and catechin. Resveratrol (found in red wine, grapes, olive oil) is a moderate antioxidant, not as potent as quercetin (citrus, apples, onions, black tea) or catechin (green teas).

Soy Isoflavones: Soy (soybeans, veggie burgers, tempeh, tofu, soy milk) is full of high-quality protein and phytochemicals. It is rich in hormone-like compounds called isoflavones (genistein, daidzein, and biochanin A) that are similar to the hormones provided by the body. Isoflavones found in soy normalize hormone levels in the body and have been shown to stop the growth of hormone-dependent cancers.

Alpha Lipoic Acid: Alpha lipoic acid (ALA) or lipoic acid is a natural antioxidant substance that is found in every cell of our bodies. It can be found in foods such as organ meats, vegetables (such as spinach, broccoli, Brussels sprouts, tomatoes, and peas), rice bran, and egg yolks. ALA is both water- and fat-soluble, enabling it to work both on the surface of cells and within them. Studies indicate that alpha lipoic acid supplements hold promise for treating various disorders, premature signs of aging, cancer prevention, liver ailments, diabetes, eye health, and skin health. In addition to its ability to protect cells from free radical damage, it enhances the effectiveness of the antioxidant vitamins C and E. These properties of lipoic acid may also benefit skin cells by improving skin texture. Many antioxidant skin care products are incorporating ALA into their formulations.

This potent and versatile antioxidant may someday be seen as a very important supplement. Research has determined that it is created in the human body and therefore is not an essential nutrient. For this reason, deficiencies of alpha lipoic acid are not known to occur in humans. There is no established recommended dietary allowance or adequate intake. The amount of alpha lipoic acid recommended by some doctors for general antioxidant protection is 100 mg, taken twice daily, although there is no clear evidence that such general use has any benefit. Alpha lipoic acid supplements may affect the optimal dose of medications used to control blood glucose in diabetics. Consult your doctor for guidance.

Other phytochemical compounds that you may have read about and their food sources include:

Onions, garlic, leeks, and chives contain allyl sulfides, which reduce the risk of certain types of cancers and lower cholesterol and blood pressure.
Turmeric contains curcumin, which has anti-inflammatory properties.
Green leafy vegetables contain glutathione, which acts as an antioxidant.
Broccoli, cauliflower, cabbage, Brussels sprouts, and bok choy contain indoles and isothiocyanates (sulforaphane), which reduce the risk of certain types of cancer.
Seeds such as flaxseeds and sunflower seeds contain lignans, which have anti-inflammatory properties.
Citrus fruit peels, cherries, and nuts contain monoterpenes, which act as antioxidants.
Whole grains and legumes contain phytic acid, which acts as an antioxidant.
Beans and legumes contain saponins, which reduce the risk of heart disease and cancer.
In Part 3, food sources rich in antioxidants with potent anti-inflammatory properties will be discussed.
Copyright 2006 Mary El-Baz. All rights reserved.

Mary El-Baz, PhD is the author of Building a Healthy Lifestyle: A Simple Nutrition and Fitness Approach and Easy and Healthful Mediterranean Cooking, an invaluable nutritional program for anyone to build a healthy lifestyle and a collection of savory, nutritious Mediterranean recipes. Dr. El-Baz holds a doctorate in Holistic Nutrition from Clayton College of Natural Health and degrees from the University of Missouri.

Look for her books on and other fine online booksellers. A forthcoming book that builds on the Building a Healthy Lifestyle foundation, Transform Your Core 6-Week Workbook, a six-week weight loss plan to rev up your fat-burning metabolism and build lean muscle to transform your midsection from fat and flabby to slim and trim, will be available just in time for your New YearÂ’s resolution!

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