Nutrition and Diet: some questions that women with ovarian cancer might ask
There is much confusing information in the media about diet and cancer. It is natural that women with ovarian cancer want to know what they should or should not be eating and whether a change in diet could influence the progression and outcome of their cancer.
In this article, one of our nurse advisers, Joan Idris, discusses some of the questions women might ask and looks at the evidence.
Should I avoid sugar?
There is a theory that says depriving cancer cells of sugar (glucose) will influence the growth of the cells as cancer cells metabolise glucose in a different way to normal cells. However in studies where people have been on a diet where all forms of sugar and carbohydrates are severely restricted, the ketogenic diet, (Schmidt et al, 2011), the blood sugar levels remain stable and there is a lack of clinical data to support any benefits regarding tumour development and progression. There have also been studies in breast cancer patients looking at whether short term fasting protects healthy cells (as they go into hibernation mode in fasting) and will make cancer cells more sensitive to chemotherapy (De Groot et al, 2015 and Safdie et al, 2009). There is no good evidence for this at the moment and further trials are being carried out.
Patients also lost weight and appetite, so there can be an adverse impact on health. Current advice is to follow healthy eating guidelines. You can find out more about sugar and cancer in this article from Cancer Research UK.
Should I cut out dairy?
Some think dairy foods have an undesirable impact on cancer development and the survival of the cancer patient. Research is scarce and it is often difficult to distinguish between the effects of calcium and milk. Hormones (oestrogen) can be present in milk, though it is unknown what percentage can survive the gastro-intestinal tract. In the UK and EU cows, goats and sheep are not allowed to be treated with growth enhancing hormones.
Studies have been carried out by the World Cancer Research Fund looking at dairy intake on the risk of developing various cancers but evidence was limited and no real conclusions were drawn.
There is even less research into dairy intake and those who have developed cancer. One study, Kroenke et al, 2013, recommended choosing low fat dairy products to reduce the risk of mortality after breast cancer diagnosis.
It can in fact be a useful source of nutrition, especially for those that find eating and drinking difficult.
Present advice is to include dairy products as part of a healthy balanced diet and choose low fat options when possible, if not underweight and the appetite is normal.
Should I avoid red and processed meat?
There has been much news about the link between red and processed meat and cancer. Red meat is beef, veal, pork, lamb, mutton, horse, goat meat. The term processed means meat has been altered through processes to enhance flavour or improve preservation, such as bacon, ham, sausages, corned beef and canned meat.
Findings from IARC (International Agency for Research on Cancer) in 2015 show that there is a positive relationship between red meat and pancreatic and prostate cancer and processed meat with colorectal cancer, though nothing specific for ovarian cancer.
It is advised to have a maximum daily intake of 90g. Though overall red and processed meat cause fewer cases of cancer in the UK than other lifestyle factors such as smoking.
Should I eat Superfoods?
These are foods thought to be rich in nutrients and anti-oxidants and are considered beneficial for health and wellbeing, such as broccoli, blueberries, pomegranates, kale. Some believe that anti-oxidants can prevent cancer, though there is no conclusive evidence for this. Also anti-oxidant supplements are not recommended for those having radiotherapy, chemotherapy or other anti-cancer treatments as anti-oxidants may help the cancer cells from breaking down.
However, evidence of anti-cancer effects of ‘superfoods’ is inconclusive but these foods are rich in vitamins and minerals and can be included as part of a balanced diet. The World Cancer Research Fund recommend a diet based on a variety of plant foods including fruit, vegetables, wholegrains and pulses.
Should I be taking turmeric?
This spice has been used in cooking for centuries. The spice is derived from the root of turmeric plant and the majority of research has focused on curcumin, which is the primary active constituent. Laboratory studies have shown that turmeric exhibits anti-inflammatory properties by inhibiting the molecules that mediate inflammatory reaction, which is why it is believed to have anti-cancer effects.
Studies in rats have shown some protection for colon, stomach and skin cancers. Also, direct application stops replication in tumour cells but it is unknown if it has this effect in the human body.
Clinical data remains limited and it is unclear whether turmeric or curcumin are beneficial in the prevention or treatment of human cancers.
There have also been reports of side effects if too much turmeric is taken, like stomach pain. Anyone taking wanting to use it for other than in cooking, should discuss this with their doctor first. You can also find more useful information here about turmeric in this article by Cancer Research UK.
Would extra vitamins and minerals help?
There is significant use of vitamin supplements in cancer patients, often without the knowledge of the medical team. They are perceived as harm-free supplements that may increase the chance of survival. Commonly used vitamins and minerals are Vitamin C, Selenium and Vitamin E, Iron, Vitamin D and multivitamins.
Vitamin C is reportedly an anti-oxidant. In high quantities it can cause gastro-intestinal disturbance, renal stones and acute haemolysis. There is no high quality evidence that oral or intravenous Vitamin C enhances anti-tumour effects of chemotherapy or reduces its toxicity. (Jacobs et al 2016)
Selenium and Vitamin E, when included with multiple other anti-oxidants, showed a reduction in chemotherapy toxicities in ovarian cancer patients (Grober et al 2016). However some doctors think that whilst there may be some toxicity reduction there is also reduction in the efficacy of the treatment as antioxidants may prevent cell damage which could stop the chemotherapy from working.
Iron is essential for cell proliferation and growth and it can contribute to both tumour initiation and tumour growth; recent work has also shown that iron has a role in the tumour microenvironment and in metastasis. (Torti and Torti 2013).
A higher intake of haem iron has shown a tendency toward a positive association with cancer risk. Evidence regarding high levels of biomarkers of iron stores (mostly with serum ferritin) suggests a negative effect toward cancer risk. More prospective studies combining research on dietary iron intake, iron biomarkers, genetic susceptibility, and other relevant factors need to be conducted to clarify these findings and better understand the role of iron in cancer development (Fonseca-Nunes et al, 2014).
Vitamin D is a fat soluble vitamin and found in dairy products, as well as formed with the action of sunshine on skin. The National Diet and Nutrition Survey 2014 found that 20% of the UK population is deficient. One study has shown this increases up to 31% in cancer patients. However, there are limited randomised trials on assessing the effects of supplementation on outcomes after diagnosis (Teleni et al 2013). Also the Scientific Advisory Committee (SACN) on Nutrition guidelines 2016 say there is insufficient evidence to make conclusions for cancer.
Multivitamin research studies vary greatly in what vitamins and combinations were used, the dosages, patient groups and treatment groups. To assess the benefit from their use in cancer needs more research.
In all these cases cancer patients should be assessed for individual deficiencies before recommending vitamin and mineral supplementation.
What about herbal remedies and supplements?
Herbs may have certain properties and many drugs are derived from plants. The common belief is that if it is natural it must be safe but there is not enough evidence for the effectiveness or safety of the various herbal supplements available.
Patients should always tell their medical team about what they intend to use as there may be interactions with their treatments e.g. St. John’s Wort can interact with some chemotherapies and glucosamine should not be taken with etoposide.
Fish oil supplements may affect platinum based chemotherapy and there can be a risk of bleeding with doses above 3g daily. Apricot kernels, sometimes known as vitamin B17, should be avoided as they contain cyanide. More information can be found from Cancer Research UK and the European Food Safety Authority.
There is little evidence for the effectiveness of antioxidants like turmeric, astralagus, spirulina and cannabis oil. They may help prevent cell damage but may also stop chemotherapy from working as well as expected as they may also be protecting cancer cells.
Herbal teas of not more than 1-3 a day, are generally thought to be harmless as they are very dilute.
It is always best to check supplements with a pharmacist if your patient wants to take these and to explain why to the patient if they are advised against.
Will Homeopathy help?
The premise for homeopathy is that ‘like cures like’ and that the more dilute the preparation is, the more powerful or potent it is. The most common dilution systems in use are decimal (X or D) which is a dilution of 1:10 and centesimal (C) which is a dilution of 1:100. The higher the number, the more dilute a preparation is. Dilutions of more than 12c or 24x are unlikely to contain any molecules of the active ingredient and would not be expected to interact with conventional medications or to cause harm. Dilutions lower than this should be checked with a pharmacist for possible interactions.
The Royal Pharmaceutical Society does not endorse homeopathy as a form of treatment because of the lack of scientific evidence for its efficacy. Also, patients should not stop taking their prescribed medication if they take a homeopathy product. There is more about homeopathy in the following links:
With thanks to The Royal Marsden hospital study day, ‘Nutrition and Cancer: What patients want to know' 22/01/18
This article is a broad overview and is not intended as patient information. Target Ovarian Cancer can’t accept responsibility for any loss or damage resulting from any inaccuracy in this information or from any external information that we link to.