Nutritional supplements or wholesome diet?

I have just returned from Kuching, Sarawak, Malaysia. My very first trip to East Malaysia was not for holiday but to give a lecture at a Liver Cancer Symposium. One of the speakers there, a palliative care physician, was recounting stories of how some retailers of mangosteen juice were targeting their sales at patients with advanced cancer and cancer patients in general. The promise of potential beneficial effects, from the potent anti-oxidant properties in mangosteen juice, was certainly a major selling point to patients who are desperate to try anything. Apparently the newest claim is that the durian skin contains powerful anti-oxidants which might be of use in treating cancer. (Durian is a local fruit with pungent soft flesh surrounded by a hard, thick thorny skin. You either love it or you are put off by the aroma!)

I am constantly being asked what to eat and what not to eat by my patients with cancer, whether there are any supplements or pills that will keep the cancer away or keep it under control. The patients and their loved ones look forlornly at me and wait with bated breath on my pronouncement.

A recent study from Harvard Medical School looked at the role of combined folic acid, vitamin B₆ and B₁₂ supplements in affecting cancer risk in women (JAMA 2008; 300: 2012 – 2021). Five thousand four hundred and forty two female health professionals aged 42 years or older participated in the Women’s Antioxidant and Folic Acid Cardiovascular Study (WAFACS). These women, with pre-existing cardiovascular disease or 3 or more coronary risk factors, were randomly assigned to receive 2.5 mg of folic acid, 50 mg of vitamin B₆ and 1 mg of vitamin B₁₂ daily or a placebo. They received the supplement from April 1998 to July 2005. None of the women taking the folic acid and vitamins were harmed. Neither did the supplements have an effect on lowering the risk for total invasive cancer or breast cancer among women. Taking the supplements also did not lower the risk of dying from any cause.

Cancer takes years to develop in our body. Its development is likely to be triggered by what we have been eating, drinking, breathing and coming into physical contact with. It takes years of exposure before the cancer emerges. Once you have developed cancer, it is logical to conclude that it would also take years for anything which has anti-cancer properties to have its beneficial effects on the cancer. At present I am not aware of any potent supplements that can retard or cure cancer in humans. Maintaining a healthy and balanced diet will certainly help your body cope with the cancer in your body. Having a healthy and balanced diet will also help you in fighting recurrence of cancer. I am certainly unaware of any large clinical studies proving the anti-cancer properties of mangosteen juice or durian skin. I do know that drinking large amount of mangosteen juice will knock a big hole in your bank account and possibly lead to severe lactic acidosis requiring hospital treatment (Am J Kidney Dis 2008; 51: 829 – 833)!