Being diagnosed with cancer can be devastating, but studies show that changes in lifestyle and diet can help tackle the development of some cancers. As part of Bowel Cancer Awareness month, we’ve written a series of posts exploring the relationship between the food you eat and cancer.
They’re all taken from Nourish: The Cancer Care Cookbook by Christine Bailey, written in partnership with experts from the wonderful Penny Brohn Cancer Care – an organization dedicated to a holistic approach to living well with cancer.
If you or someone you know has cancer, just being aware of the impact diet can have on resistance to cancer can be a great help. Read on for information about how certain kinds of food can have an impact on cancer develops, and try this Wilted Kale Salad recipe to discover how this super-food can help protect against cancer.
The link between diet and cancer
Cancer is on the increase, and it is estimated that 50 per cent of people alive today will be diagnosed with the disease in their lifetime. Experts from the World Cancer Research Fund and the American Institute for Cancer Research reviewed the evidence in 2007 and agreed that diet is the single most important factor responsible for this massive rise. It is likely to be responsible for 35 per cent of all cancers – an even greater risk than cigarette smoking. They issued clear guidelines: aim to be slim without being underweight; avoid sugary drinks; eat a variety of healthy whole foods, mainly of plant origin; eat less red and processed meats; and limit alcohol and salt intake.
To understand why diet makes such a difference, it helps to know a little about how cancer develops. Cancer takes advantage of unhealthy environments in the body and uses sophisticated processes to spread. Some of these environments and processes are explained below, as well as how good food can help to protect you.
Foods that control the growth of cancer cells
Cancer cells use angiogenesis (the creation of new blood vessels) to supply the oxygen and nutrients they need in order to grow. Angiogenesis is a naturally occurring process in your body, but in a cancerous situation the rate of new blood-vessel formation is abnormally rapid. Scientists have discovered natural food products that help to stop the creation of new blood vessels and are testing them for their potential therapeutic use. By including foods such as shallots, garlic, soya beans, cruciferous vegetables, citrus fruit, spices, green tea and many herbs, you benefit from their anti-angiogenic properties, thereby helping to slow down the creation of the new blood vessels that help cancerous cells to grow.
Why avoiding inflammation is important
Persistent inflammation, swelling or redness, creates an environment that supports cancer at all stages of tumour development, and so foods that help to minimize this are very important. If you include in your diet more omega-3 fatty acids (found in oily fish) but fewer omega-6 essential fatty acids (found in polyunsaturated cooking oils, such as sunflower and vegetable, and in margarines and processed foods), this helps your body to reduce any inflammation. The fibre, vitamins and other antioxidants found in fruit, vegetables and whole grains can also help to reduce inflammation. What is more, recent research shows that omega-3 fatty acids may be able to boost the anti-cancer effect of the breast-cancer drug Tamoxifen.
On the other hand, trans-fats (found in margarines and processed foods) and too many omega-6 fatty acids can encourage inflammation. Not only do they contribute to conditions that favour cancer but they can also contribute to heart disease, atherosclerosis, metabolic syndrome and other chronic conditions.
Beyond this, foods with a high glycaemic index (GI) and glycaemic load (GL) create a pro-inflammatory environment in the body. White bread, white rice (excluding basmati rice), most cereals and foods containing sugar are some of the foods with high GI and GL values. They all make inflammation more likely and/or more pronounced.
Most people enjoy sugar, so it can be hard to accept that it undermines health. Nevertheless, there are several links between sugar, inflammation and cancer growth, which is why reducing sugar consumption is a major step towards protecting your well-being.
Vitamin D is thought to have a key role in reducing inflammation in the body. Mainly, vitamin D can be made in the body by the daily action of sunlight on the skin, without burning. Vitamin D-rich foods include oily fish, shellfish, egg yolks, mushrooms and butter.
Slowing down cell division
Cancer cells tend to multiply rapidly, but some foods are able to arrest their growth by interfering with the process of cell division; for example, indole-3-carbinol (I3C) stops cancer cells dividing by locking away an enzyme called elastase. I3C is found in cruciferous vegetables – eating vegetables such as cabbage, kale, cauliflower and broccoli, therefore, slows down the rate at which cancer cells multiply.
You can alter your genes with your lifestyle
It is common to believe that our genes determine the risk of developing cancer and that it is coded into our DNA at birth. In fact, only 5–10 per cent of cancers are caused by hereditary factors. Studies from a relatively new branch of biology, called epigenetics, are showing how the genes we inherit are affected by lifestyle, dietary choices and events. This illustrates how genes are not always our destiny and that the lifestyle choices we make can be very powerful in controlling them; a diet rich in folic acid, for example, found in green vegetables, helps to promote healthy epigenetic processes and resists the formation and spread of cancerous cells.
Cancer growth can also be stimulated by hormonal imbalances. This is more evident in hormone-sensitive cancers such as breast and prostate cancer. Being overweight or obese increases the risk of these cancers, as well as others including endometrial, colon, pancreatic and kidney. Obesity also induces insulin resistance. This is where the body no longer tolerates high levels of glucose, causing insulin levels to rise. Insulin works as a growth factor for many cells, especially those in the colon. And, if these cells grow out of control, they can become cancerous. In advanced stages of cancer, insulin resistance contributes to weight loss and feeling weak.
Being a healthy weight is an important step towards protecting yourself from hormone-sensitive cancers, insulin resistance and other chronic diseases.
Stress can damage your body
The production of free radicals is a normal chemical reaction in the body; however, we live in a world that promotes the over-production of free radicals: smoking and drinking alcohol, as well as environmental pollution and stress, are just some of the triggers that prompt their formation. When the body is in contact with too many free radicals, it is unable to limit the cell damage they cause, and this accumulates over time. The result is known as oxidative stress, which drives cancer initiation and development. More recent studies suggest that cancer cells may also deliberately create oxidative stress around them to destroy the normal cells and steal their nutrients for their own use.
Antioxidants are chemicals that “mop up” free radicals and reduce their damaging effects. The damage of free radicals in the body can be limited by including foods that are rich in antioxidants, such as vitamins C and E, and the minerals selenium and zinc. Plant foods are your first choice for these nutrients: vegetables, fruit, seeds and nuts. Zinc and selenium are also found in meat and seafood.
Kale’s glucosinolates make it a great food to protect against many forms of cancer. When it’s wilted and served with toasted seeds and cherry tomatoes, it makes a pretty delicious salad too! Here’s how to make it > >
Nourish: The Cancer Care Cookbook embraces the holistic healthy living approach of Penny Brohn Cancer Care, combining nutritional advice with 7-day menu plans and healthy recipes design to help you, or someone you know, live with cancer.
Click here to order your copy with free UK postage