There are so many reports of agents that may cause cancer, that there is a temptation to dismiss them all. Tabloid newspapers have listed everything from babies, belts, biscuits, and bras, to skiing, shaving, soup, and space travel as factors. On the other hand, it is also tempting to be drawn into debates about more esoteric candidates for causative agents like hair dyes, underarm deodorants, or pesticides. Even if they did contribute to cancer, a claim unverified by large-scale studies, it would only be by a tiny amount.
The most important message is that there are major factors which contribute to cancer which can be modified. These are lifestyle factors which together contribute to a third of all cancers. The top causes are:
- Smoking tobacco.
- Being overweight or obese; including factors such as food and alcohol consumption, combined with lack of exercise.
- Exposure to the sun when it can damage your skin.
Smoking tobacco is linked to 16 different cancers and contributes to a fifth of cancers overall. Two out of every three smokers will die of a smoking-related illness and on average reduce their lifespans by 10 years compared to non-smokers. That should be reason enough to quit.
Obesity has a large impact on common cancers. It is attributed as the cause of 10% of bowel cancers and 8% of breast cancers. With some less common cancers it has an even greater impact – for example, up to 26% of endometrial cancers (cancers of the lining of the uterus).
Given these staggering statistics, what should you eat to prevent cancer?
We often hear stories of specific foods preventing specific cancers, from pomegranates and prostate cancer, to broccoli and breast cancer. But these reports are often from studies too small to be very accurate. What we can be certain of, from large studies, reinforces common sense. A diet that has more fresh fruit and vegetables, and less processed foods high in sugars, salt and fats is healthier. Not only will it help weight control, but fruits and vegetables are a source of antioxidants and fibre which will also help reduce cancer risk. Likewise, white meats like fish with omega 3 polyunsaturated fats may protect against cancer. Increasing consumption of red meats, as well as processed and preserved meats like salami or bacon can increase the risk of bowel and other cancers. In fact, the World Health Organisation recently released a statement on the links between processed meats and colorectal cancer. There has been much written about supplementing the diet with vitamins and antioxidants, but the best way of ingesting these nutrients is through food.
Related to diet, another important modifiable risk factor is alcohol. It’s implicated in 6% of all cancers, including common cancers like breast and bowel cancer. Up to one third of head and neck cancers have alcohol as part of their cause. The risk of cancer increases with greater alcohol consumption irrespective of the type of alcohol consumed.
The next of the major preventable lifestyle factors is sun exposure. This is most important when the sun’s rays are intense enough to damage the skin, and later cause cancer. When the UV index is 3 or more, particularly in the middle hours of a day, the skin and eyes should be protected with clothing, a hat, sunglasses, and at least SPF 30+ broad spectrum sunscreen to any exposed skin. Seeking shade from direct sunlight is preferable.
Having dealt with the top three lifestyle issues affecting cancer, there are other aspects of prevention to be aware of.
Some cancers develop after viral infections, and there are now vaccines which can prevent the development of such cancers. The most important is the vaccine against strains of human papilloma virus (HPV), which will help prevent HPV infection, and therefore the later development of cervical, penile, anal, or oropharyngeal cancer. Given to preteen girls and boys, it has proven a very safe vaccine. If followed with intermittent cervical screening for the HPV virus, this should almost eliminate cancer of the cervix. Similarly, vaccinating high-risk groups (i.e. those having unprotected sex, sharing needles, or working with human blood) against hepatitis B, will prevent the development of hepatitis B associated liver cancer.
Although there are other preventable cancers such as those due to occupational exposures to cancer-causing agents like asbestos or chemicals, further general advice is to participate in population cancer screening programs, which can both prevent cancers by detecting and treating changes in tissues prior to invasive cancer, or finding early invasive cancers which can be cured. The 3 programs proven to save lives are: cervical cancer screening (originally with Pap smears and now HPV tests), breast cancer mammographic screening, and bowel screening with faecal immunochemical tests.
Over the course of this article, the most important ways to prevent cancer have been highlighted. These are:
- Stopping smoking
- Watching one’s weight; eating and drinking sensibly, as well as exercising
- Avoiding sun exposure
- Vaccines and screenings
Despite this, myths about a variety of other possibilities continue. Consequently, it is worth consulting with websites of authoritative cancer organisations, to explore whether such claims have any basis in fact, before committing to extreme measures in the hope that cancer will be prevented. Unfortunately, we have no fail-safe method of cancer prevention, but by paying attention to lifestyle and screening methods, the old adage may keep its relevance – that ‘prevention is better than cure.’
Featured Image Credit: ‘Cancer’, by PDPics, CC0 via Pixabay.