How to reduce your risk of cancer with a healthy diet

Cancer is a highly emotive subject, and it often presents many physical and emotional challenges. One in two people in the UK will develop cancer in their lifetime so being able to talk openly and objectively is helpful. The good news is that 30 to 40 per cent of cases could be prevented by addressing lifestyle habits, so there is reason to feel positive.

Focusing on diet and nutrition is an important place to start. A diet centred around healthy plant foods, while minimising or avoiding ultra-processed food and meat, is a key recommendation for cancer prevention.

People consuming vegan and vegetarian diets have consistently lower rates of cancer than meat eaters. A fibre-rich diet consisting of fruit, vegetables, whole grains, beans, nuts and seeds and herbs and spices, maximises the consumption of anti-cancer compounds found in food. This leads to a healthier gut microbiome, lower levels of inflammation and cellular stress and a healthier body weight—all important for preventing cancer.

Although no one food defines a healthy or unhealthy diet, the one food to leave off the plate is processed meat, since it is known to be a direct cause of cancer.

Of course, diet alone cannot guarantee a life free of cancer but what has emerged is that a healthy plant-based diet can improve your chances of remission and survival after a cancer diagnosis. For example, one of the largest studies conducted on diet and health in post-menopausal women reported that participants assigned to consume more fruit, vegetables and whole grains had a longer remission and survival after a diagnosis of breast cancer.

Similarly, in colorectal cancer, a more plant-based diet has been associated with a longer remission and survival. With regards to prostate cancer, men consuming more plant-based foods have a lower PSA level, a marker of prostate cancer growth.

A seminal study by Dr Dean Ornish, a pioneer of lifestyle medicine, showed that a plant-based diet alongside other healthy habits can halt the progression of early-stage prostate cancer, with a direct impact on the expression of cancer-related genes. An exciting recent development is the recognition that the health of the gut microbiome impacts response and outcomes to therapies that target the immune system and that a fibre-rich diet, abundant in healthy plant-foods predicts for a longer remission. 

While I don’t believe in superfoods, some plant foods do stand out when it comes to their anti-cancer properties. Top of our list would be cruciferous vegetables of the Brassicaceae family. Examples include broccoli, rocket, cabbage and Brussels sprouts. Their anti-cancer effects are thought to be due to the sulphur-containing compounds called glucosinolates. Through cooking, chewing and digestion they are converted to compounds such as indole-3-carbinol and sulphoraphane, which act at a cellular level to prevent cancer. A fun fact is that broccoli sprouts can have up to 100 times higher amounts of sulphoraphane than the broccoli heads.

Mushrooms also appear to have particular anti-cancer properties. A review of 17 observational studies concluded that consuming mushrooms at least five times per week lowered the risk of cancer by 44 per cent. Mushrooms contain many compounds that may be responsible for the beneficial effects, with beta-glucan thought to be one. It is a type of fibre that has also been shown to benefit the immune system and interestingly is also found in nutritional yeast.

Other foods to emphasise include tomatoes and other red coloured fruit and vegetables that contain lycopene, a type of carotenoid, that has been associated with a lower risk of prostate cancer. The allium family of vegetables including onion, garlic and leeks contain beneficial sulphur compounds which have been associated with a lower risk of cancer, particularly stomach and oesophageal cancer.

One of the most underrated foods is soya. The consumption of minimally processed forms such as tofu, tempeh, edamame beans and soya milk has been associated with an array of health benefits and a reduced risk of many of our commonest cancers, including breast and prostate cancer. The anti-cancer properties are due to compounds called isoflavones, a type of phyto-oestrogen, which acts to slow down the growth of cancer cells. The isoflavones also support bone health and can counter menopausal symptoms, all useful properties when recovering from cancer treatment. Swapping cow’s dairy for soya milk is also an excellent option given that dairy consumption increases the risk of prostate cancer and may increase the risk of breast and endometrial cancer, whereas soya milk seems to have a protective effect.

Alongside a healthy diet, there are other lifestyle habits to keep in mind. We are familiar with the fact that tobacco is a cause of cancer, and hence should be avoided. But people remain confused about whether consuming alcohol is beneficial or harmful. There is little doubt that alcohol is a cause of cancer, contributing to around five per cent of cancer cases globally and is best avoided.

Regular physical activity has a number of benefits for both physical and mental health. Both aerobic and strength building exercise has been shown to reduce the risk of cancer by supporting a healthier body weight and immune system, keeping hormone levels in check, reducing inflammation and supporting better gut health. Incorporating any movement into your daily routine is better than none, so make sure to prioritise this and get going with any activity you enjoy.

For overall health and wellbeing don’t forget to focus on getting regular, restorative sleep, managing stress, maintaining healthy relationships and spending time in nature. These lifestyle factors are equally important for preventing and living well after a cancer diagnosis.