The term ‘superfood’ was recently created, probably as a marketing strategy so as to associate health properties with certain food. These often include blueberries, broccoli, raspberries, green tea and many more. Pertaining to cancer, these superfoods are hailed to be able to prevent and cure cancer!
The usual explanation to support the anti-cancer claim is that these superfoods contain high amounts of antioxidants. To most people, antioxidants are the best solution to prevent and cure cancers. This may be due to a few laboratory tests of pure compounds isolated from the food. However, the readers tend to ignore that food contains many other ingredients than just those pure compounds. Some of these compounds, which are not purified and isolated, may have no or negative effects on the antioxidant compounds. Therefore, it is inappropriate and scientifically wrong to generalise the findings of ‘superfood’ in cancer.
Moreover, the claims of ‘antioxidant is the cure for cancer’ is highly debatable. European Food Safety Authority (EFSA) found no evidence that the antioxidant activities in the lab was of any benefit to human health. In addition, antioxidant can also induce oxidative stress, which can promote the cancer formation and development. In mouse skin cancer models, the researchers were shocked to confirm that oxidative stress actually interfered with the spread of cancer by reducing it. Treating these mice with antioxidants decreased oxidative stress and accelerated the rate of cancer cells metastasizing (spread of cancer to other parts of the body). Another study revealed that supplementing the diet with antioxidants such as N-acetylcysteine (NAC) and vitamin E, hastened cancer progression and reduced survival of mice with lung cancer. Based on the evidence compiled from the National Cancer Institute (NCI), all of the randomized controlled clinical trials with no conflict of interest and conducted by NCI, did not provide evidence that dietary antioxidant supplements were beneficial in preventing cancer in people who do not have cancer. 5 United States Preventive Services Task Force (USPSTF) also conducted a systematic review on dietary antioxidants supplements and found no clear evidence in preventing cancer.
… antioxidants decreased oxidative stress and accelerated the rate of cancer cells metastasizing …
Eating vegetables and fruits every day in our balanced diet is a good healthy habit to maintain. However, if you have an intention to rely on specific food, you may have off-set the balanced diet which can be detrimental to health. A balanced diet is the key to maintain the state of good health. Supplements can be useful to add-on to what we are lacking from our diet. At this moment, to say that certain foods are able to prevent or cure cancer, it is a claim with no solid scientific evidence.
- Cancer Research United Kingdom. Superfood. Available from http://www.cancerresearchuk.org/about-cancer/causes-of-cancer/diet-and-cancer/food-controversies#collapsefood_controversies6 [Accessed on 11 March 2018]
- EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Guidance on the scientific requirements for health claims related to antioxidants, oxidative damage and cardiovascular health. EFSA Journal 2011;9(12):2474.
- Piskounova E, Agathocleous M, Murphy MM, Hu Z, Huddlestun SE, Zhao Z, Leitch AM, Johnson TM, DeBerardinis RJ, Morrison SJ. Oxidative stress inhibits distant metastasis by human melanoma cells. Nature. 2015 Nov 12;527(7577):186-91.
- Sayin VI, Ibrahim MX, Larsson E, Nilsson JA, Lindahl P, Bergo MO. Antioxidants accelerate lung cancer progression in mice. Sci Transl Med. 2014 Jan 29;6(221):221ra15.
- National Cancer Institute. Antioxidants and Cancer. Available from https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/antioxidants-fact-sheet [Accessed on 11 March 2018]
- Fortmann SP, Burda BU, Senger CA, et al. Vitamin and mineral supplements in the primary prevention of cardiovascular disease and cancer: an updated systematic evidence review for the U.S. Preventive Services Task Force. Annals of Internal Medicine 2013.