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Antioxidants to the rescue
Antioxidants are a group of nutrients crucial to health and well-being. Their value has been confirmed by a great deal of research over the last 25 years. But public awareness of antioxidants is more recent, dating from the mid-1990s, so many people are unclear how antioxidants help prevent degenerative diseases such as cancer, heart disease, osteoarthritis, and cataracts.
To appreciate antioxidants, you must understand "free radicals": unstable, highly reactive oxygen molecules (ions) that circulate in the bloodstream. To become chemically stable, free radicals snatch electrons from other molecules in the body, a process that causes cell damage (oxidative damage).
Your normal metabolic processes release some free radicals, but your body repairs most of the oxidative damage these natural free radicals cause. However, if you flood your bloodstream with an unusually large number of free radicals -- by smoking or by eating a high-fat diet -- over time, oxidative damage can overwhelm the body's repair mechanisms, setting you up for degenerative diseases.
Antioxidants prevent oxidative damage by donating electrons to free radicals. Antioxidants include several vitamins (C, E, and the vitamin A family, called carotenoids, which includes beta-carotene); several minerals (notably selenium); some enzymes (glutathione); an amino acid (N-acetylcysteine); and one vitamin-like compound (coenzyme Q-10).
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You May Need More Antioxidants if You:
- Smoke
- Eat a high-fat diet
- Eat fewer than five servings of fruits and vegetables a day
- Are over age 55
- Are under significant, chronic emotional stress
- Have a history of heart disease, cancer, or another chronic medical condition
- Have recently had a significant injury or surgery
- Exercise very strenuously
- Are exposed to significant environmental pollution
What Works Best -- and Worst -- with Antioxidants
- Antioxidants work together to fight the damaging effects of free radicals. So if you are taking individual antioxidants and you increase your intake of one antioxidant, you should increase the others by a proportionate amount. If you are taking an antioxidant complex, the components are already proportionate and balanced for you.
- Tobacco decreases absorption of some vitamins, so smokers may require supplemental antioxidants.
- Absorption is maximized when ingested with food.
Forms Available
- Commonly available as caplets or tablets.
- Available in a multivitamin complex.
- Available in an antioxidant complex.
- Individual antioxidants are usually available separately.
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The Antioxidant Lineup
The three major antioxidant vitamins:
- Vitamin A and carotenoids: fight free radicals and help promote healthy skin, strong nails, and good eyesight.
- Vitamin C: one of the most essential vitamins and a major antioxidant. Combats cell damage. Unlike vitamin A and vitamin E, vitamin C is water soluble, so it attacks free radicals in body fluid as opposed to fat tissue.
- Vitamin E: like vitamin C and beta-carotene (a precursor of vitamin A), vitamin E is an excellent antioxidant. Helps the body absorb free-radical molecules and reduces the damage they cause.
Other antioxidants:
- Selenium: responsible for making glutathione, the body's most abundant antioxidant enzyme. Protects the body from harmful free radicals and helps boost the immune system and eliminate toxins.
- Coenzyme-Q10: also known as ubiquinone, this antioxidant stimulates body cells to produce the fuel that gives you energy and keeps your body running smoothly.
- Lipoic acid: helps combat the free radicals that can damage your cells; also plays an important role in the conversion of food into energy.
- Glutathione and N-acetylcysteine (NAC): protects cells from free-radical damage that occurs from toxic environmental chemicals and pollutants, stress, smoking, and aging. Glutathione is a powerful and abundant antioxidant enzyme, and NAC is a necessary amino acid and the precursor to glutathione.
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Known Benefits of Antioxidants
- Antioxidants protect your cells from the damage caused by free radicals, unstable compounds that result from lifestyle factors like environmental stress and strenuous exercise as well as natural processes like aging.
Individual antioxidants also have many other benefits independent of their antioxidant properties. Refer to each antioxidant:Common Dosage Range for Antioxidants
- Vitamin C: 500 to 1,000 mg
- Vitamin A: 1,000 to 6,000 RE
- Vitamin E: 200 to 600 IU
- Coenzyme-Q10: 15 to 30 mg
- Lipoic Acid: 20 to 50 mg
- Selenium: 100 to 200 mcg
- Glutathione and N-acetylcysteine (NAC): 50 to 100 mg for glutathione and 500 to 600 mg for NAC
Dietary Sources
Food Tips
The best dietary sources are fruits and vegetables. The National Cancer Institute urges everyone to eat at least five servings of fruits and vegetables a day. Fruits and vegetables contain generous amounts of antioxidants no matter how you eat them: fresh, frozen, canned, dried, or lightly cooked. However, some antioxidants are best consumed in fresh foods (vitamin C), while others are best consumed lightly cooked (vitamin A). The important point is to eat fruits and vegetables at every meal, to snack on them, and to limit the fat in your diet because fat introduces free radicals into the bloodstream.
Foods High in Antioxidants
| Foods High in Vitamin A | Serving Size | Amount of Vitamin A | Units |
|---|
Beef liver
Chicken liver
Apricots, fresh
Asparagus, cooked
Beet greens
Broccoli, cooked
Cantaloupe
Carrot, raw
Collard greens, cooked
Kale, cooked
Orange
Peach
Pepper, sweet red
Prunes, stewed
Spinach, cooked
Squash, winter
Sweet potato, cooked
Tomato
Tomato juice
Turnip greens, cooked
| 3 ounces
3 1/2 ounces
3
1 cup
1/2 cup
1/2 cup
1 cup
1 medium
1/2 cup
1/2 cup
1 medium
1 large
1/2 cup
1/2 cup
1/2 cup
1/2 cup
1 medium
1 medium
6 ounces
1/2 cup
| 9000
4913
289
122
370
194
272
810
741
456
40
203
222.5
106.5
729
656
923
111
146
457
| RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
|
| Foods High in Vitamin C | Serving Size | Amount of C | Units |
|---|
Acerola
Broccoli (cooked)
Brussels sprouts
Cantaloupe
Cauliflower (raw)
Cranberry juice
Grapefruit (pink)
Grapefruit (white)
Grapefruit (canned)
Grapefruit juice (canned)
Grapefruit juice (fresh)
Guava
Honeydew melon
Kale, cooked
Kiwi
Lemon
Lime
Mango
Orange (mandarin)
Orange (navel)
Orange (Valencia)
Orange juice (concentrate)
Orange juice (fresh)
Papaya
Pepper (green bell)
Pepper (yellow bell)
Pomelo
Strawberries
Sunny Delight
Tang powder
| 1 cup
1/2 cup
1/2 cup
1 cup pieces
1/2 cup
6 ounce
1/2 medium
1/2 medium
1/2 cup
8 oz.
8 oz.
1 medium
1 cup pieces
1/2 cup
1 medium
1 medium
1 medium
1 medium
1/2 cup canned
1 medium
1 medium
8 oz.
8 oz.
1 medium
1/2 cup
1 medium
1 cup pieces
1 cup
6 oz.
6 oz.
| 1644
58
48
68
36
67
47
39
42
72
94
165
42
27
75
31
20
57
43
80
59
97
97
188
45
341
116
85
60
60
| mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
|
| Foods High in Vitamin E | Serving Size | Amount of E | Units | IU |
|---|
Almond oil
Almonds, dry roasted
Avocado
Corn oil
Hazelnuts
Mango
Peanut butter
Peanuts
Safflower oil
Sunflower oil
Sunflower seeds
Sweet potato
Wheat germ
Wheat germ oil
| 1 tablespoon
1 ounce
1/2 medium
1 tablespoon
1 ounce
1 medium
2 tablespoons
1 ounce
1 tablespoon
1 tablespoon
1 ounce
1 medium
1/4 cup
1 tablespoon
| 5.3
6.72
2.32
1.9
6.7
2.32
3
2.56
4.6
6.3
14.18
5.93
4.08
20.3
| mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
| 5.3
6.72
2.32
1.9
6.7
2.32
3
2.56
4.6
6.3
14.18
5.93
4.08
20.3
|
| Foods High in Selenium |
|---|
Fish
Seafoods
Chicken
Kidney
Liver
Brown rice
Broccoli
Brewer's yeast
Mushroom
Cabbage
Onions
Cucumber
Whole grains
Celery
Radishes
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When and How to Take Antioxidants
- Take with or immediately after meals to reduce stomach irritation and enhance absorption.
- Swallow tablets whole with a full glass of liquid.
What to Take with Antioxidants
- Take with food to enhance absorption and reduce stomach irritation.
- Antioxidants work together, much like the individual B vitamins in a B complex.
What Not to Take with Antioxidants
- Tobacco decreases absorption of some antioxidants, including vitamins C, A, and E.
- Alcohol reduces bodily stores of vitamin A and beta-carotene.
- Antioxidants work together in the correct proportions, but excess consumption of one individual antioxidant may interfere with the absorption of another. If you take individual antioxidants separately, do not increase the dosage of one antioxidant by itself. Consult your doctor before taking high doses of any supplement.
Storage
- Keep antioxidants in a cool, dry place away from light and moisture.
- Don't store them in your bathroom medicine cabinet, as heat and moisture can make antioxidants less effective. A refrigerator may also be too moist and/or cold. A cabinet or drawer is best.
- Store safely out of children's reach.
Recommended Daily Allowance for Antioxidants
RDA (recommended daily allowance) values are set as the minimum needed to offset deficiency or disease, not as an actual value needed for optimum health.
Note: coenzyme-Q10, lipoic acid, glutathione, and NAC do not have RDAs.
| ANTIOXIDANT | RDA/MEN | RDA/WOMEN |
|---|
Vitamin A
Vitamin C
Vitamin E
Selenium
|
1000 RE
60 mg
10 IU
70 mcg
|
800 RE
60 mg
8 IU
55 mcg
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Warnings
Consult a physician before use or do not use vitamin B complex if:- You are about to start a high-dose supplement program.
Or if you:
- Have hemochromatosis, as vitamin C enhances the absorption of iron.
- Have a predisposition to form kidney stones. Vitamin C is metabolized to oxalate, a component of kidney stones. However, a link between vitamin C and kidney stone formation has not been proven in healthy adults.
- Are pregnant or breastfeeding.
- Are a smoker. Studies show that beta-carotene supplements may increase the risk of lung cancer.
- Have a blood clotting disorder. Doses of over 1,200 mg per day of vitamin E may increase blood clotting times.
- Have diabetes. Lipoic acid can alter your blood glucose level.
Some Antioxidants May Have Interactions with the Following
- Alcohol: regular use lowers vitamin C level in the tissues; also increases the risk of liver damage from vitamin A and reduces vitamin A reserves.
- Anticoagulants: combination with high levels of vitamin E increases risk of bleeding.
- Aspirin: prolonged administration lowers the level of circulating ascorbic acid.
- Caffeine: reduces vitamin A reserves.
- Cholestyramine: decreases vitamin A absorption.
- Cortisone: reduces liver stores of vitamin A.
- Isotretinoin: increases the risk of vitamin A toxicity.
- Estrogens: alone or as an ingredient in some oral contraceptives, estrogens lower the level of circulating ascorbic acid.
- Laxatives: prolonged use of laxatives like mineral oil and docusate can cause deficiency of fat-soluble vitamins, including vitamin E.
- Oral contraceptives: increase vitamin A levels and reduce plasma vitamin E levels.
- Phenobarbital and other barbiturates: reduce vitamin A reserves.
- Sucralfate: increases the risk of vitamin A toxicity.
- Tetracycline: prolonged administration lowers the level of circulating ascorbic acid.
- Tobacco: speeds up the elimination of vitamin C.
- Warfarin: it has been suggested that effects of warfarin can be prevented by doses of vitamin C greater than 4 grams.
Side Effects
Side effects can differ depending on the individual antioxidant. If you are taking a multivitamin with antioxidants, or an antioxidant complex, the ratio of the individual antioxidants are proportionate and balanced. Increasing or decreasing one component will increase or decrease the other components, respectively. If you are taking individual antioxidants, be careful not to take too much of one component. Follow your doctor's suggestions or the manufacturer's recommendations. Consult your doctor before starting a high-dose regimen of any vitamin.
Refer to the following individual antioxidants for the possible side effects. If antioxidants are taken in the proper amounts and as directed, potential side effects can usually be avoided:
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Sources & Further Reading
Books
- 1. Machlin, LJ.Handbook of Vitamins, Second Ed. New York: Marcel Dekker, Inc., 1991.
- 2. Basu, TK and Dickerson, JW.Vitamins in Human Health and Disease. UK: CAB Intl., 1996.
- 3. Groff, JL, Gropper, SS, Hunt, SM. Advanced Nutrition and Human Metabolism, Second Ed. St. Paul: West Pub. Co., 1995.
- 4. Werbach, MR. Nutritional Influences on Illness, Second Ed. Tarzana, CA: Third Line Press, 1996.
- 5. Meletis, CD and Jacobs, T. The Practitioner's Guide to Drug-Nutrient and Nutrient-Nutrient Interactions. 1996.
- 6. Kastrup EK et al. Drug Facts and Comparisons. Facts and Comparisons.
- 7. Papas, AM et al. Antioxidant Status, Diet, Nutrition and Health. Boca Raton: CRC Press, LLC, 1999.
- 8. Fauci et al. Harrison's Principles of Internal Medicine, Fourteenth Ed. McGraw-Hill Co., Inc. 1998.
- 9. Bendich, A and Deckelbaum, RJ. Preventive Nutrition: The Comprehensive Guide for Health Professionals. Totowa, NJ: Humana Press, 1997.
- 10. Pence, BC and Dunn, DM. Nutrition & Women's Cancers. Boca Raton: CRC Press, LLC, 1998.
- 11. Dell, BL and Sunde, RA. Handbook of Nutritionally Essential Mineral Elements. New York: Marcel Dekker, Inc., 1997.
12. Duke, James A. The Green Pharmacy. New York: St. Martin's Paperbacks, 1997
13. Murray, Michael. The Healing Power of Herbs. Rocklin, CA: Prima Publishing, 1995
14. Murray, Michael. Encyclopedia of Nutritional Supplements. Rocklin, CA: Prima Publishing, 1996
15. Facts and Comparisons: The Review of Natural Products. Facts and Comparisons, 1998
16. Lieberman, Shari, N. Bruning. The Real Vitamin & Mineral Book. Garden City Park, NY: Avery Publishing Group, 1997
17. Balch, James, F., P.A. Balch. Prescription for Nutritional Healing. Garden City Park, NY: Avery Publishing Group, 1997
Find more books on health and wellness at  barnesandnoble.com.
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