Here are some recurrent unproven claims:
Mobile phones and Wi-Fi can cause cancer. False. Radio waves from mobile networks do not carry enough energy to damage DNA, contrary to so-called ionising-radiation, such as the Sun’s ultraviolet rays. “It is true that the International Agency for Research on Cancer (IARC) has classified non-ionising radio frequency radiation (such as that used by mobile phones) as ‘possibly carcinogenic’”, states the Cancer Research UK website. “But that’s also how the IARC classifies aloe vera and bracken fern [a common house plant].” The Cancer.gov website offers similar counter-arguments.
Aspartame can cause cancer. False. Also from Cancer Research UK: “The European Food Safety Authority (EFSA) has set an acceptable daily intake (ADI) for aspartame. It equals around 14 cans of diet fizzy drink for a person who weighs around 70kg. This is more cans than most people would have in one day.”
Underwired bras can cause breast cancer. False. This rumour has been around for a long time. One of the notions behind it is that “underwired bras restrict the circulation of lymph fluid – which it does not”, again according to Cancer Research UK. “In reality, lymph fluid travels up and into the underarm lymph nodes, not towards the underwire.”
Deodorants can cause breast cancer. False. “Some reports have suggested that these products contain harmful substances, such as aluminum compounds and parabens, that can be absorbed through the skin or enter the body through nicks caused by shaving. The evidence to date suggests these products don't cause cancer”, says the Mayo Clinic website, advising people to avoid products that contain these chemicals if they are truly worried.
Genetically manipulated (GM) foods can cause cancer. False. First, there are no good explanations to account for a cancer-promoting effect in these foods. Also from the Cancer Research UK website, “people worry that GM foods are unnatural and might be harmful. But we have been changing genes of living things for hundreds of years, by selecting plants and animals to breed”, and this has never been linked to cancer.
A blow to the breast can cause cancer. False. Of course, it can cause a lump to appear, but that’s not cancer.
Bisphenol A (BPA) in plastic containers and bottles can cause cancer. False. Even when the plastic is heated and if BPA “leaks” into food or water, studies that have suggested chemicals found in plastics have cancer-causing effects involved experiments with human cells in a lab or with animals, not humans, according to Cancer Research UK. And the way the cells came into contact with plastics was totally different from what would happen in the human body. One thing the Mayo Clinic website recommends is nonetheless to avoid using containers that are not microwave-safe for heating food in the microwave.
Attitude determines the risk of getting or surviving cancer. False. According to the Cancer.gov website, “to date, there is no convincing scientific evidence that links a person’s “attitude” to their risk of developing or dying from cancer.” It is normal for cancer patients to sometimes feel sad, angry, discouraged – and at other times positive. What appears to be true is that people with a positive attitude may be more likely to maintain social connections and stay active, and physical activity and emotional support may in turn help cope with cancer.
There are many more claims like these. Maybe some of these claims might one day prove to be true, but for the time being there is just not enough evidence to support them – and perhaps there will never be. Meanwhile, it is much more beneficial to focus on the real known dangers – and to stop smoking, drink moderately, eat healthily and avoid sunbathing, among others. All these lifestyle habits are certain to substantially reduce cancer risk.
Sources:
https://www.cancerresearchuk.org/
https://www.mayoclinic.org/
https://www.cancer.gov/
Text by Ana Gerschenfeld, Health & Science Writer of the Champalimaud Foundation.
Reviewed by Professor António Parreira, Clinical Director of the Champalimaud Clinical Centre.
