Taurine has been shown to be depleted in people taking chemotherapy.¹ It remains unclear how important this effect is or if people taking chemotherapy should take taurine supplements.

Acetyl-L-carnitine in the amount of 1,000 mg three times per day for eight weeks, has been shown to improve nerve damage (neuropathy) caused by paclitaxel.²

Chemotherapy frequently causes mouth sores. In one trial, people were given approximately 400,000 IU of beta-carotene per day for three weeks and then 125,000 IU per day for an additional four weeks.³ Those taking beta-carotene still suffered mouth sores, but the mouth sores developed later and tended to be less severe than mouth sores that formed in people receiving the same chemotherapy without beta-carotene.

In a study of chemotherapy-induced mouth sores, six of nine patients who applied vitamin E directly to their mouth sores had complete resolution of the sores compared with one of nine patients who applied placebo.⁴ Others have confirmed the potential for vitamin E to help people with chemotherapy-induced mouth sores.⁵ Applying vitamin E only once per day was helpful to only some groups of patients in another trial,⁶ and not all studies have found vitamin E to be effective.⁷ Until more is known, if vitamin E is used in an attempt to reduce chemotherapy-induced mouth sores, it should be applied topically twice per day and should probably be in the tocopherol (versus tocopheryl) form. In another study, supplementation with vitamin E orally (600 IU per day) reduced the incidence of paclitaxel-induced nerve damage.⁸

A liquid preparation of German chamomile has been shown to reduce the incidence of mouth sores in people receiving radiation and systemic chemotherapy treatment in an uncontrolled study. ⁹

Russian research has looked at using eleuthero with chemotherapy. One study of patients with melanoma found that chemotherapy was less toxic when eleuthero was given simultaneously. Similarly, women with inoperable breast cancer given eleuthero were reported to tolerate more chemotherapy.¹⁰ Eleuthero treatment was also associated with improved immune function in women with breast cancer treated with chemotherapy and radiation.¹¹

Though cancer cells use glutamine as a fuel source, studies in humans have not found that glutamine stimulates growth of cancers in people taking chemotherapy.^{14 , 15} In fact, animal studies show that glutamine may actually decrease tumor growth while increasing susceptibility of cancer cells to radiation and chemotherapy,^{16 , 17} though such effects have not yet been studied in humans.

Glutamine has successfully reduced chemotherapy-induced mouth sores. In one trial, people were given 4 grams of glutamine in an oral rinse, which was swished around the mouth and then swallowed twice per day.¹⁸ Thirteen of fourteen people in the study had fewer days with mouth sores as a result. These excellent results have been duplicated in some,¹⁹ but not all²⁰ double-blind research. In another study, patients receiving high-dose paclitaxel and melphalan had significantly fewer episodes of oral ulcers and bleeding when they took 6 grams of glutamine four times daily along with the chemotherapy.²¹ In another preliminary trial, supplementation with 10 grams of glutamine three times per day, beginning 24 hours after administration of high-dose paclitaxel, reduced the severity of drug-induced nerve damage (peripheral neuropathy).²²

One double-blind trial suggested that 6 grams of glutamine taken three times per day can decrease diarrhea caused by chemotherapy.²³ However, other studies using higher amounts or intravenous glutamine have not reported this effect.^{24 , 25}

Intravenous use of glutamine in people undergoing bone marrow transplants, a procedure sometimes used to allow very high amounts of chemotherapy to be used, has led to reduced hospital stays, leading to a savings of over $21,000 for each patient given glutamine.²⁶

Paclitaxel commonly causes muscle and joint pain. Five cases of people experiencing these symptoms who responded to the amino acid glutamine have been reported.²⁷ All five were given 10 grams glutamine by mouth three times per day beginning 24 hours after the paclitaxel treatment. Although the report does not state how many days glutamine supplements were taken, it may have been for ten days or less—the typical time it takes for these symptoms to subside following paclitaxel administration. Whereas all five had experienced moderate to severe symptoms from the drug when taken previously without glutamine, none of the five experienced these symptoms when glutamine was added. In another study, patients receiving high-dose paclitaxel and melphalan had significantly fewer episodes of oral ulcers and bleeding when they took 6 g of glutamine four times daily along with the chemotherapy.²⁸

Glutamate, an amino acid structurally related to glutamine, had previously been reported to reduce paclitaxel-induced nerve damage in animals.²⁹

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.³⁰ 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.³¹ Vitamin C appears to increase the effectiveness of chemotherapy in animals³² and with human breast cancer cells in test tube research.³³ 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.³⁴

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.³⁵

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.³⁶

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.³⁷

Patients with inoperable head and neck cancer were treated with a spleen peptide preparation (Polyerga) in a double-blind trial during chemotherapy with cisplatin and 5-FU.³⁸ The spleen preparation had a significant stabilizing effect on certain white blood cells. People taking it also experienced stabilized body weight and a reduction in the fatigue and inertia that usually accompany this combination of chemotherapy agents.

Peptides or short proteins derived from the thymus gland, an important immune organ, have been used in conjunction with chemotherapy drugs for people with cancer. One study using thymosin fraction V in combination with chemotherapy, compared with chemotherapy alone, found significantly longer survival times in the thymosin fraction V group.³⁹ A related substance, thymostimulin, decreased some side effects of chemotherapy and increased survival time compared with chemotherapy alone.⁴⁰ A third product, thymic extract TP1, was shown to improve immune function in people treated with chemotherapy compared with effects of chemotherapy alone.⁴¹ Thymic peptides need to be administered by injection. People interested in their combined use with chemotherapy should consult a doctor.

Chemotherapy frequently causes mouth sores. In one trial, people were given approximately 400,000 IU of beta-carotene per day for three weeks and then 125,000 IU per day for an additional four weeks.⁴² Those taking beta-carotene still suffered mouth sores, but the mouth sores developed later and tended to be less severe than mouth sores that formed in people receiving the same chemotherapy without beta-carotene.

In a study of chemotherapy-induced mouth sores, six of nine patients who applied vitamin E directly to their mouth sores had complete resolution of the sores compared with one of nine patients who applied placebo.⁴³ Others have confirmed the potential for vitamin E to help people with chemotherapy-induced mouth sores.⁴⁴ Applying vitamin E only once per day was helpful to only some groups of patients in another trial,⁴⁵ and not all studies have found vitamin E to be effective.⁴⁶ Until more is known, if vitamin E is used in an attempt to reduce chemotherapy-induced mouth sores, it should be applied topically twice per day and should probably be in the tocopherol (versus tocopheryl) form. In another study, supplementation with vitamin E orally (600 IU per day) reduced the incidence of paclitaxel-induced nerve damage.⁴⁷

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.⁴⁸ 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.⁴⁹ Vitamin C appears to increase the effectiveness of chemotherapy in animals⁵⁰ and with human breast cancer cells in test tube research.⁵¹ 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.⁵²

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.⁵³

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.⁵⁴

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.⁵⁵

Milk thistle’s major flavonoids, known collectively as silymarin, have shown synergistic actions with the chemotherapy drugs cisplatin and doxorubicin (Adriamycin®) in test tubes.⁵⁶ Silymarin also offsets the kidney toxicity of cisplatin in animals.⁵⁷ Silymarin has not yet been studied in humans treated with cisplatin. Research with a limited number of chemotherapy drugs suggest that silymarin does not interfere with their anticancer effect. However, additional research is needed.⁵⁸

The mushroom Coriolus versicolor contains an immune-stimulating substance called polysaccharide krestin, or PSK. PSK has been shown in several studies to help cancer patients undergoing chemotherapy. One study involved women with estrogen receptor-negative breast cancer. PSK combined with chemotherapy significantly prolonged survival time compared with chemotherapy alone.⁵⁹ Another study followed women with breast cancer who were given chemotherapy with or without PSK. The PSK-plus-chemotherapy group had a 25% better chance of survival after ten years compared with those taking chemotherapy without PSK.⁶⁰ Another study investigated people who had surgically removed colon cancer. They were given chemotherapy with or without PSK. Those given PSK had a longer disease-free period and longer survival time.⁶¹ Three grams of PSK were taken orally each day in these studies.

Although PSK is rarely available in the United States, hot-water extract products made from Coriolus versicolor mushrooms are available. These products may have activity related to that of PSK, but their use with chemotherapy has not been studied.

Melatonin supplementation (20 mg per day) has decreased toxicity and improved effectiveness of chemotherapy with paclitaxel.⁶²

Echinacea is a popular immune-boosting herb that has been investigated for use with chemotherapy. One study investigated the actions of cyclophosphamide, echinacea, and thymus gland extracts to treat advanced cancer patients. Although small and uncontrolled, this trial suggested that the combination modestly extended the life span of some patients with inoperable cancers.⁶³ Signs of restoration of immune function were seen in these patients.

Many chemotherapy drugs can cause diarrhea, lack of appetite, vomiting, and damage to the gastrointestinal tract. Recent anti-nausea prescription medications are often effective. Nonetheless, nutritional deficiencies still occur.⁶⁴ It makes sense for people undergoing chemotherapy to take a high-potency multivitamin-mineral to protect against deficiencies.

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.⁶⁵ 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.⁶⁶ Vitamin C appears to increase the effectiveness of chemotherapy in animals⁶⁷ and with human breast cancer cells in test tube research.⁶⁸ 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.⁶⁹

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.⁷⁰

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.⁷¹

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.⁷²

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 the article strongly suggests that antioxidants need not be avoided for fear that the actions of chemotherapy would be interfered with.⁷⁸

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.⁷⁹

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.⁸⁰