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Antioxidants for Sports & Fitness

Why Use

Antioxidants and Free Radicals

Why Do Athletes Use It?*

Some athletes say that antioxidants help protect the body from free radicals.

What Do the Advocates Say?*

Antioxidants such as vitamin C, vitamin E, CoQ10, glutathione, and alpha lipoic acid are important supplements for everyone, but especially for those who exercise on a regular basis. The rational is that exercise is a highly oxidative process and, as a consequence, produces free radicals from aerobic metabolism. Antioxidant compounds help alleviate this process.

There is conflicting evidence whether the best time to supplement with an antioxidant is before or after a workout.

*Athletes and fitness advocates may claim benefits for this supplement based on their personal or professional experience. These are individual opinions and testimonials that may or may not be supported by controlled clinical studies or published scientific articles.

Dosage & Side Effects

Antioxidants and Free Radicals

How Much Is Usually Taken by Athletes?

Most research has demonstrated that strenuous exercise increases production of harmful substances called free radicals, which can damage muscle tissue and result in inflammation and muscle soreness. Exercising in cities or smoggy areas also increases exposure to free radicals. Antioxidants, including vitamin C and vitamin E, neutralize free radicals before they can damage the body, so antioxidants may aid in exercise recovery. Regular exercise increases the efficiency of the antioxidant defense system, potentially reducing the amount of supplemental antioxidants that might otherwise be needed for protection. However, at least theoretically, supplements of antioxidant vitamins may be beneficial for older or untrained people or athletes who are undertaking an especially vigorous training protocol or athletic event.1 , 2

Placebo-controlled research, some of it double-blind, has shown that taking 400 to 3,000 mg of vitamin C per day for several days before and after intense exercise may reduce pain and speed up muscle strength recovery.3 , 4 , 5 However, taking vitamin C only after such exercise was not effective in another double-blind study.6 While some research has reported that vitamin E supplementation in the amount of 800 to 1,200 IU per day reduces biochemical measures of free-radical activity and muscle damage caused by strenuous exercise,7 , 8 , 9 several studies have not found such benefits,10 , 11 , 12 , 13 and no research has investigated the effect of vitamin E on performance-related measures of strenuous exercise recovery. A combination of 90 mg per day of coenzyme Q10 and a very small amount of vitamin E did not produce any protective effects for marathon runners in one double-blind trial,14 while in another double-blind trial a combination of 50 mg per day of zinc and 3 mg per day of copper significantly reduced evidence of post-exercise free radical activity.15

In most well-controlled studies, exercise performance has not been shown to improve following supplementation with vitamin C, unless a deficiency exists, as might occur in athletes with unhealthy or irrational eating patterns.16 , 17 Similarly, vitamin E has not benefited exercise performance,18 , 19 except possibly at high altitudes.20 , 21

Side Effects

Antioxidants include many different nutrients, each of which has potential side effects. Look up the unique side effects for each and discuss the potential benefits and risks with your doctor or pharmacist before adding antioxidants, such as:

Interactions with Supplements, Foods, & Other Compounds

Antioxidants include many different nutrients, each of which has the potential to interact with drugs. Look up the unique interactions for each and discuss the potential benefits and risks of your current medications with your doctor or pharmacist before adding antioxidants, such as:

Interactions with Medicines

Certain medicines interact with this supplement.

What Are Drug Interactions
Types of interactions: Beneficial Adverse Check

Replenish Depleted Nutrients

  • none

Reduce Side Effects

  • none

Support Medicine

  • Docetaxel

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.22 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.23 Vitamin C appears to increase the effectiveness of chemotherapy in animals24 and with human breast cancer cells in test tube research.25 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.26

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but it clearly shows that antioxidants need not be avoided for fear that the actions of chemotherapy are interfered with.27 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    A new formulation of selenium (Seleno-Kappacarrageenan) was found to reduce kidney damage and white blood cell–lowering effects of cisplatin in one human study. However, the level used in this study (4,000 mcg per day) is potentially toxic and should only be used under the supervision of a doctor.28

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Paclitaxel

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.29 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.30 Vitamin C appears to increase the effectiveness of chemotherapy in animals31 and with human breast cancer cells in test tube research.32 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.33

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but the article strongly suggests that antioxidants need not be avoided for fear that the actions of chemotherapy would be interfered with.34

    A new formulation of selenium (Seleno-Kappacarrageenan) was found to reduce kidney damage and white blood cell–lowering effects of cisplatin in one human study. However, the level used in this study (4,000 mcg per day) is potentially toxic and should only be used under the supervision of a doctor.35

    Glutathione , the main antioxidant found within cells, is frequently depleted in individuals on chemotherapy and/or radiation. Preliminary studies have found that intravenously injected glutathione may decrease some of the adverse effects of chemotherapy and radiation, such as diarrhea.36

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.

Reduces Effectiveness

  • none

Potential Negative Interaction

  • Atorvastatin
    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Lovastatin
    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Pravastatin
    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Rosuvastatin
    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Simvastatin
    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.

Explanation Required

  • Busulfan

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.37 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.38 Vitamin C appears to increase the effectiveness of chemotherapy in animals39 and with human breast cancer cells in test tube research.40 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.41

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.42 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Carboplatin

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.43 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.44 Vitamin C appears to increase the effectiveness of chemotherapy in animals45 and with human breast cancer cells in test tube research.46 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.47

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.48 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Chlorambucil

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.49 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.50 Vitamin C appears to increase the effectiveness of chemotherapy in animals51 and with human breast cancer cells in test tube research.52 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.53

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.54 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Cladribine

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.55 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.56 Vitamin C appears to increase the effectiveness of chemotherapy in animals57 and with human breast cancer cells in test tube research.58 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.59

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.60 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Erlotinib

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.61 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.62 Vitamin C appears to increase the effectiveness of chemotherapy in animals63 and with human breast cancer cells in test tube research.64 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.65

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.66 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Floxuridine

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.67 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.68 Vitamin C appears to increase the effectiveness of chemotherapy in animals69 and with human breast cancer cells in test tube research.70 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.71

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.72 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Fludarabine

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.73 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.74 Vitamin C appears to increase the effectiveness of chemotherapy in animals75 and with human breast cancer cells in test tube research.76 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.77

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.78 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Irinotecan

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.79 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.80 Vitamin C appears to increase the effectiveness of chemotherapy in animals81 and with human breast cancer cells in test tube research.82 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.83

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.84 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Lomustine

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.85 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.86 Vitamin C appears to increase the effectiveness of chemotherapy in animals87 and with human breast cancer cells in test tube research.88 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.89

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.90 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Mechlorethamine

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.91 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.92 Vitamin C appears to increase the effectiveness of chemotherapy in animals93 and with human breast cancer cells in test tube research.94 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.95

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.96 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Melphalan

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.97 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.98 Vitamin C appears to increase the effectiveness of chemotherapy in animals99 and with human breast cancer cells in test tube research.100 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.101

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.102 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Mercaptopurine

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.103 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.104 Vitamin C appears to increase the effectiveness of chemotherapy in animals105 and with human breast cancer cells in test tube research.106 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.107

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.108 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Polifeprosan 20 with Carmustine

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.109 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.110 Vitamin C appears to increase the effectiveness of chemotherapy in animals111 and with human breast cancer cells in test tube research.112 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.113

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.114 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Thioguanine

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.115 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.116 Vitamin C appears to increase the effectiveness of chemotherapy in animals117 and with human breast cancer cells in test tube research.118 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.119

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.120 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Thiotepa

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.121 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.122 Vitamin C appears to increase the effectiveness of chemotherapy in animals123 and with human breast cancer cells in test tube research.124 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.125

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.126 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Uracil Mustard

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.127 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.128 Vitamin C appears to increase the effectiveness of chemotherapy in animals129 and with human breast cancer cells in test tube research.130 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.131

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.132 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.
  • Vincristine

    Chemotherapy can injure cancer cells by creating oxidative damage. As a result, some oncologists recommend that patients avoid supplementing antioxidants if they are undergoing chemotherapy. Limited test tube research occasionally does support the idea that an antioxidant can interfere with oxidative damage to cancer cells.133 However, most scientific research does not support this supposition.

    A modified form of vitamin A has been reported to work synergistically with chemotherapy in test tube research.134 Vitamin C appears to increase the effectiveness of chemotherapy in animals135 and with human breast cancer cells in test tube research.136 In a double-blind study, Japanese researchers found that the combination of vitamin E, vitamin C, and N-acetyl cysteine (NAC)—all antioxidants—protected against chemotherapy-induced heart damage without interfering with the action of the chemotherapy.137

    A comprehensive review of antioxidants and chemotherapy leaves open the question of whether supplemental antioxidants definitely help people with chemotherapy side effects, but neither does it show that antioxidants should be avoided for fear that the actions of chemotherapy are interfered with.138 Although research remains incomplete, the idea that people taking chemotherapy should avoid antioxidants is not supported by scientific research.

    The interaction is supported by preliminary, weak, fragmentary, and/or contradictory scientific evidence.

More Resources

Antioxidants and Free Radicals

Resources

See a list of books, periodicals, and other resources for this and related topics.

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