Should I take vitamins when having chemotherapy?

This is an issue that has been talked about for a while. We don't really know what effect (if any) taking vitamin or mineral supplements has on chemotherapy. Some doctors are wary of patients taking anything that boosts the immune system while they are being treated. They think that the effect of the chemotherapy may be reduced if you are taking anything that helps cells to recover. There is some evidence to suggest that antioxidants like co-enzyme Q10, selenium and vitamins A, C and E might reduce the activity of radiotherapy and chemotherapy drugs which generate free radicals, for example, alkylating agents and doxorubicin. The Royal College of Radiologists advise that until more is known, patients should avoid antioxidant supplements, especially in high doses, during their conventional cancer therapy. There could be a risk that the vitamins help cancer cells to recover too. This may not be the case, but at the moment there is so little research that we just don't know.

A systematic review by Cochrane in 2009 looked at the research that has been carried out into people taking selenium to ease the side effects of chemotherapy, radiotherapy and surgery. This review found that selenium did not help the side effects. The people taking the selenium did not have any side effects from taking it but some did overdose. We need more research to look at the dose that people should take and to look into this further.

A survey of cancer patients in the UK has shown that about half of the people having chemotherapy are taking some sort of complementary therapy, alternative therapy or vitamin supplement. The researchers tried to look into the advice these people had been given on what they were taking. Hardly any of them had been given any advice at all. Those who had, were most often warned about echinacea if they were having chemotherapy for lymphoma. There is a worry that echincea could interfere with treatment because it affects the immune system. Pharmacists were particularly worried about echinacea in people having treatment with steroids or monoclonal antibodies, rather than those on chemotherapy. Pharmacists also warned about

• Cod liver oil, evening primrose, gingko and garlic because they can all affect blood clotting and possibly blood clotting drugs, such as warfarin
• Kava kava because it can be toxic to the liver
• Beta carotene (vitamin A) because it can increase lung or prostate cancer risk in smokers
• St John's Wort because it may interact with hormones, antibiotics or chemotherapy

We need a lot more research into these substances and how they interact with conventional medicines and cancers. This research will come, but it all takes time.

Guidance by the Royal College of Radiologists advises that very little is known about the interactions between cancer treatments and nutritional supplements. They advise that if If you are not able to eat a normal, balanced diet and want to take vitamin supplements or an alternative or complementary remedy, you can take a good-quality, one-a-day multivitamin and minerals pill, making sure not to exceed the stated dose. It is helpful to talk to your doctor about this first.

The main thing during chemotherapy is not to give yourself a hard time. Try to eat if you can. But don't get upset if there are days when you can't. You will be able to make up the for it between treatments and after your treatment has finished. Drink plenty to flush the drugs through your kidneys. You must try to drink even if you are feeling sick. Your health will be affected by not drinking much more quickly than by not eating. If you are having problems with sickness or diarrhoea, then you must tell your specialist or chemotherapy nurse. There are medicines you can have to help control these side effects. Try to take gentle exercise every day. But make sure you rest too. Your body needs to recover and rest is essential.