Many breast cancer patients who undergo chemotherapy are given Taxol (paclitaxel) as part of their regimen. Chemotherapy is designed to destroy any remaining cancer cells in the breast and the remainder of the body. Chemotherapy is effective in improving breast cancer survivorship: numerous studies have found that it protects against breast cancer recurrence and death.

Taxol and other taxanes (e.g., Taxotere (docetaxel)) can result in side effects such as hair loss, mouth sores, nausea, fatigue, low white blood cell count, neuropathy, muscle and joint pain, cognitive impairment (chemo brain) and serious infections. While obtaining relief from these side effects obviously is desirable, it is very important for breast cancer patients to avoid consuming foods or taking supplements that will lessen the cytotoxic impact of chemotherapy on breast cancer cells.

Avoid most supplements during chemotherapy

Taking multivitamins during chemotherapy might help protect cancer cells from the toxic effects of the treatment and we do not recommend it. A variety of other micronutrients (curcumin, EGCG, gamma-linolenic acid (GLA), I3C, DIM, luteolin, quercetin and resveratrol) have been studied and found to increase the effectiveness of Taxol in laboratory experiments. The relevant studies are presented in our article on what to eat during Taxol chemotherapy. However, safe and effective dosages for these supplements during chemotherapy have not been established. We suggest obtaining these compounds by consuming food rather than taking them in concentrated form. Taking them separately from the other micronutrients found in foods could have unintended adverse effects. For example, one study reported that resveratrol alone promoted mammary tumor growth and metastasis in a mouse model of estrogen receptor negative (ER-) breast cancer, whereas it inhibited it in combination with quercetin and catechin (all three polyphenols are found in grapes).

Milk thistle, a relative of artichoke, traditionally has been used for its liver-protective properties, but increasingly is being used by cancer patients. Milk thistle is the best known source of the compound flavonoid silymarin, which contains silybin. Silybin has been shown to inhibit growth and induce apoptosis in human breast cancer cells and HER-2/neu overexpressing (HER2+) mammary tumors in a mouse model. However, one study found that treatment of human breast cancer tumors in rodents with silymarin isolated from milk thistle stimulated cancer growth. Therefore, we caution breast cancer patients against taking concentrated milk thistle, artichoke or silymarin supplements.

While consuming fatty fish such as salmon is recommended during Taxol treatment, recent research suggests that fish oil supplements should not be used by those undergoing chemotherapy. Some fish oil preparations contain fatty acids that can induce resistance to a broad spectrum of chemotherapy drugs in minute quantities.

Note that curcumin (found in turmeric) has been shown to be an iron chelator, which could negatively impact some women undergoing chemotherapy by reducing their iron stores.

Beta blockers and Taxol

There is some evidence that beta blocker use during chemotherapy could enhance its effectiveness, especially against triple negative breast cancer. Beta blockers are used to treat hypertension, abnormal heart rhythms, and heart failure. Of the beta blockers studied, propranolol (Inderal) appears to have the strongest synergistic effects when combined with Taxol.

Exercise during chemotherapy

Regular exercise has been shown to reduce fatigue in cancer patients undergoing chemotherapy. However, one study suggested that intense or prolonged physical activity a couple of days before the start of radiation or chemotherapy has significant potential to reduce the benefits of the treatments. Based on the available evidence, light to moderate aerobic exercise appears to be safe during treatment with Taxol and could reduce fatigue.