Cancer is one of the leading causes of death in the world. According to the latest updated data provided by the World Health Organization, 14 million new cases were diagnosed in 2012 and this number is expected to increase by 70% in the coming decades. In Spain, according to the forecasts of the Spanish Society of Medical Oncology, 246,713 new cases of cancer will be diagnosed in 2020, compared to the 215,534 cases that were diagnosed in 2012. The most frequent tumors are colon cancer, followed by prostate cancer , lung, breast and bladder . An estimated 3 out of 10 men and 2 out of 10 women died of cancer in 2012.
In 2015, the prestigious journal Science published research that concluded that two thirds of cancers are due to ‘bad luck’ or chance, that is, to random mutations that occur during DNA replication ; while only a third is attributed to external and environmental factors in which we can influence, through certain lifestyles. These figures caused extensive debate and in 2016 the journal Nature published a study in which it was concluded that lifestyle and exposure to certain environmental risk factors influence the development of 70-90% of cancers. This study highlighted that the control of certain factors such as the consumption of tobacco, alcohol, a poor diet and physical inactivity can modulate the risk of developing cancer.
Epidemiological data tell us that, for example, in the UK 43% of cancer cases and 50% of deaths caused by cancer itself in 2010 were attributed to lifestyle and environmental factors. Despite the discrepancies in the percentages, today we know that many types of cancer are caused by an unhealthy lifestyle and that this ‘bad luck’, deep down, is not as influential as previously thought. But what habits can help us reduce the risk of cancer?
A higher body mass index – which is the ratio between weight (kg) and height (meters) squared and, therefore, dependent on your weight – is associated with an increased risk of suffering from 17 of the 22 most common types of cancer . Thus, reducing obesity through physical exercise and diet, and reducing the intake of sugars and saturated fats , is an effective method to reduce the risk of cancer. In addition, the consumption of processed foods and products rich in sugar increases the risk of prostate cancer by up to three times, while the consumption of complex carbohydrates and fiber, present in legumes, fruits and whole grains, is associated with a lower risk of colorectal cancer, breast and prostate cancer.
Physical activity reduces the risk of cancer by reducing obesity but also by releasing chemicals that the muscle releases into the blood and is distributed throughout all tissues of the body. In a study involving about a million and a half people, it was found that those who performed higher levels of physical activity in their free time showed a lower risk of developing 13 of the 26 types of cancer analyzed. Recently, active women have been shown to have up to a 71% lower risk of breast cancer , regardless of whether they are thin or overweight.
Another known culprit for increasing the risk of cancer, specifically lung cancer , is tobacco. According to estimates by the Spanish Association Against Cancer, up to 90% of lung cancers occur in smokers, while 30% of cancer deaths may be caused by tobacco. However, alcohol also increases the risk of some types of cancer. An estimated 3.6% of all cancers are attributed to alcohol consumption. Although the negative effect comes from alcohol abuse, some evidence suggests that the intake of a daily alcoholic beverage increases the risk of cancer for the oropharyngeal cavity, esophagus and breast.
Different types of radiation can increase the risk of some forms of cancer. Thus, prolonged exposure to non-ionizing ultraviolet radiation, that of the Sun, can cause skin cancer or melanoma, the most common form of cancer in the world. Ionizing radiation, such as that used for medical imaging, can induce some types of cancer.
In conclusion, beyond the ‘bad luck’ that accompanies the risk of suffering from some tumors, following certain lifestyles will increase our chances of suffering from cancer. Cancer is not all random, but each person has the power to minimize their risk through habits that reduce obesity, physical inactivity, alcohol and tobacco consumption, or prolonged exposure to radiation. In fact, the so-called ‘toxic triad of cancer’, which includes physical inactivity, low physical condition and obesity, increases cancer incidence and mortality.
Helios Pareja is a researcher and professor at the Doctorate and Research School of the European University; Javier Morales Rojas is a researcher at the Doctoral and Research School of the European University.
