For decades, cancer was primarily linked to smoking and genetics. However, according to Adam Barsouk, an oncology fellow at Johns Hopkins University, there is much more to the story. While survival rates for certain cancers have improved significantly, with breast cancer 10-year survival reaching 83% in the US, a worrying trend has emerged: cancer rates in young people have more than doubled over the past 30 years, even as smoking rates decline. This paradox suggests new drivers, such as obesity, which affects 70% of US adults and 66% in the UK, and is associated with almost every type of solid malignancy.
The Role of Inflammation and Gut Health
Excess fatty tissue triggers chronic inflammation, impairing the immune system's ability to distinguish healthy cells from cancerous ones. An imbalance in the gut microbiome, known as dysbiosis, further exacerbates this inflammation. Ultra-processed foods, prevalent in modern diets, are a major contributor to dysbiosis. Unlike autoimmune conditions, dysbiosis causes low-level, persistent inflammation that can create an environment conducive to cancer growth. Barsouk emphasises that while cancer involves an element of chance, reducing inflammation through diet and weight management can significantly lower risk.
Prevention: A Realistic Goal
Barsouk highlights that 40-50% of cancer deaths are preventable, equating to 4 million lives annually worldwide. Key strategies include maintaining a healthy weight, reducing alcohol intake, avoiding smoking, and minimising consumption of ultra-processed foods. Even small changes, such as switching from white to wholewheat bread or reducing alcohol from ten to three drinks per week, can yield substantial benefits. Moderation is crucial; the best diet is one that can be sustained long-term.
The Mystery of Helicobacter pylori
H. pylori, a common bacterium, is linked to stomach cancer, but its effects vary by ethnicity and diet. East Asian populations, despite low obesity rates, have high gastric cancer incidence due to pickled and salted foods. In contrast, India, with high H. pylori prevalence, has lower stomach cancer rates, possibly due to a plant-based diet. This underscores the importance of dietary factors. Fermented foods like kimchi and miso, however, promote gut health and are not harmful.
Screening Saves Lives
Early detection through colonoscopies, mammograms, and cervical smears dramatically improves outcomes. However, screening rates have declined since the pandemic, partly due to distrust in the medical profession and misinformation online. Barsouk urges people to rely on evidence-based information and to participate in recommended screenings. His book, Outsmarting Cancer: Risk Reduction and the Power of Prevention, aims to provide accessible, science-backed guidance to help individuals reduce their cancer risk.
