Cancer has become the leading cause of death in the world: in 2020, almost 10 million deaths were attributed to cancer, that is to say, nearly 1 in 6 of all deaths recorded as unnatural. The most common types of cancer are breast, lung, colon and rectum, and prostate.
Around one-third of deaths from cancer are due to tobacco use, high body mass index, alcohol consumption, low fruit and vegetable intake together with an excessive consumption of processed foods and lack of physical activity.
The most important population risk factors are body weight, diet, and physical activity. According to the European Code Against Cancer, at least 18 % of diagnosed cases of cancer are related to excess body weight, physical inactivity, alcohol consumption or poor nutrition, and could therefore be prevented. Recent studies indicate that diet is directly linked to the initiation and development of various types of cancer, such as colon and breast cancer: 40 % of tumours in men and 60 % of tumours in women are related to diet and more than 30 % of cancer deaths are due to this same cause.
In this debate, we will attempt to answer several key questions: Why can diet affect the development of cancer? What population data support this? What are the most relevant studies of this subject internationally, and what data do they stress particularly? What types of foods may be the most harmful? What are antioxidants and what do they have to do with cancer? What benefits does the Mediterranean diet provide? Does eating less fat reduce the risk of cancer? What is fibre in food, and can it reduce the risk of cancer? How does processed meat, how meat is cooked and so on affect the risk of cancer? And, given the multifactorial causes of cancer, how much can each of these affect its development? What probabilities do recent studies suggest? By increasing the amount of physical activity, do we decrease the risk of cancer?
Marina Pollán, research professor from the Centro Nacional de Epidemiología of the Instituto de Salud Carlos III (CNE-ISCIII) and Scientific Director of CIBERESP.
Marcos Malumbres, principal researcher of the Cell Division and Cancer Group at the Centro Nacional de Investigaciones Oncológicas (CNIO) of Madrid and scientific trustee of the Asociación Española contra el Cáncer. Leads the CaixaResearch project Stem cell therapy to treat Type I diabetes.
Núria Jar, journalist specialising in science and health.