Each year on October 19, World Breast Cancer Day is observed, bringing attention to one of the most common cancers among women, according to the World Health Organization (WHO). In 2022, there were over 2.3 million reported cases and approximately 670,000 deaths worldwide. This type of cancer often manifests as a painless lump or thickening in the breast, underscoring the importance of consulting a healthcare provider if any unusual swelling is detected. While being female is the primary risk factor for breast cancer, it is noteworthy that between 0.5% and 1% of cases also affect men.
As with various other cancer types, lifestyle choices significantly influence the likelihood of developing breast cancer. Nutritionist Juan Revenga describes cancer as akin to a lottery, suggesting that everyone is born with tickets for this lottery. Throughout life, individuals may acquire more tickets or discard some, but they can neither get rid of all their tickets nor avoid the risk entirely, even with a healthy lifestyle.
The role of diet in this context should be viewed as part of a broader healthy lifestyle, which also includes minimizing exposure to carcinogenic substances and prioritizing adequate rest and physical activity. Understanding the connection between diet and breast cancer risk has been a focus of research, particularly highlighted in a report published by the World Cancer Research Fund and the American Institute for Cancer Research (IARC) in 2018. This report outlines scientific insights on diet, physical activity, and biological processes related to the disease.
Within the report”s findings, a clear distinction is made between varying levels of evidence and corresponding recommendations. It is confirmed that intense physical activity and breastfeeding can lower the risk of developing breast cancer, while alcohol consumption raises that risk. However, when it comes to specific foods and their links to breast cancer, the WCRF and IARC stress that evidence is often limited or weak.
The dietary recommendations with limited evidence for the prevention of breast cancer include the consumption of non-starchy vegetables and foods rich in carotenoids. For premenopausal women, dairy products and calcium-rich diets are also suggested. Various foods, such as grains, dietary fiber, fruits, soy, red and processed meats, poultry, fish, and eggs, remain inconclusive regarding their relationship with breast cancer.
The American Cancer Society further adds that eating patterns high in plant-based foods and low in animal products and refined carbohydrates can reduce risk. Revenga emphasizes the importance of adopting a comprehensive approach to cancer prevention, asserting that recommendations should be viewed holistically. He notes that general advice for cancer prevention applies across all types of cancer, even if certain factors might be more closely linked to specific cancers.
Certain conditions, such as being female, represent unavoidable risks for breast cancer. The European Code Against Cancer outlines twelve recommendations, five of which pertain to nutrition: maintaining a healthy weight, engaging in daily physical activity, consuming a balanced diet rich in whole grains, legumes, fruits, and vegetables while limiting high-calorie foods, sugary drinks, and processed meats; restricting or ideally avoiding alcohol consumption; and encouraging breastfeeding when possible.
Concerning whether all foods have a positive or negative relationship with cancer, research has sought to address this question. A 2013 study published in The American Journal of Clinical Nutrition analyzed 50 common ingredients from a popular cookbook, investigating their associations with cancer risk as reported in various studies found in the National Library of Medicine”s database. Notably, around 80% of these ingredients had some form of association with cancer, though contradictory studies exist—some identifying certain ingredients as risk factors while others claim protective properties.
Revenga, in a video for the Catalan Federation of Entities Against Cancer, points out that while many studies reach conclusive interpretations, they often rely on weak statistical evidence. Individual studies that evaluate single ingredients typically offer more categorical conclusions than comprehensive reviews and meta-analyses. He concludes that cancer garners significant attention, leading to a search for dietary solutions, whether for relief or prevention, often resulting in exaggerated claims based on limited knowledge.
