Does a Healthy Diet Reduce Cancer Risk?
Q & A with Mrs. Debra Lindsay (Dietitian)
We often cannot explain why one person develops cancer and another does not. But research shows that certain risk factors related to your diet and lifestyle can increase your chances of developing cancer. Conversely, there are many foods that contain powerful nutrients and chemicals that help the body to protect itself from cancer cells.
Cancer Risk Factors
The most common diet and lifestyle risk factors for cancer include:
- Alcohol consumption
- A high fat diet
- A low fibre diet
- A diet high in sugar and refined foods
- A diet low in fruits and vegetables
- A diet high in nitrates and nitrites
- Lack of physical activity and being overweight
All of these risk factors can be avoided by following a healthy diet and lifestyle.
Having more than two drinks each day for many years may increase the chance of developing cancers of the mouth, throat, esophagus, larynx, liver, and breast. The risk increases with the amount of alcohol that a person drinks. For most of these cancers, the risk is higher for a drinker who also uses tobacco.
It is advisable to drink alcohol in moderation. This means no more than one drink per day for women and no more than two drinks per day for men. Unfortunately, it is not advisable to save all your drinks during the week and drink them all on Friday night!
Red wine contains a compound called resveratrol, found in red and black grape skins, which is a very potent antioxidant that can help protect the body from free radical damage. If you like to drink alcohol, your tipple of choice should therefore be a glass of good red wine.
A high fat diet
Eating a diet high in fat, especially saturated fats like those found in meat and dairy products can increase your risk of developing certain cancers, like colon, uterus, prostate and breast cancer. Choose lean meats, eat more chicken and fish and eat low fat or fat free dairy products.
Try to eat moderate amounts of fat in your diet, and mostly in the form of unsaturated oils like those found in nuts and seeds, avocado pear, olives, olive oil and grape seed oil. Eat these oils in their natural, raw form if possible, and avoid cooking with them as the heat can damage the oils and reduce their health-giving properties.
A low fibre diet
Eating a diet that is low in roughage and fibre increases your risk of developing colon as well as breast cancer. A high fibre diet helps the body to reduce dietary iron absorption as many high fibre foods contain a chemical called IP6 that binds to iron in your gut and stops the body from absorbing it. High levels of iron in the body can increase the levels of oxidation and free radicals increasing the risk of cancer.
Try to eat plenty of unrefined and wholegrain and foods like oats, brown or whole wheat bread, brown rice, unrefined cereals, fresh fruit, vegetables, dried beans and lentils every day. These foods are also much richer in other nutrients and are tasty too.
A diet high in sugar and refined foods
Eating a diet that contains a lot of refined and sweetened foods increases your body’s production of IGF (Insulin-like Growth Factor), which has been shown to stimulate the growth of cancer cells. Try to avoid having a daily fix of something sweet and reduce your intake of these foods to the occasional treat.
A diet low in fresh fruit and vegetables
Mother Nature has provided us with a vast array of colourful and nutritious fruit and vegetables to choose from. The more colourful, the more nutritious your fruit and vegetables are. Dark green, black, blue, red, orange and yellow fruit and vegetables contain a number of phytochemicals (phyto=plant) that have many cancer fighting and health promoting properties. Current recommendations are that we should try to eat 5-7 portions of fruit and vegetables every day.
One portion of fruit is equivalent to 1 medium sized fruit, ½ a cup of chopped fruit or 125ml of pure fruit juice (freshly squeezed is always best). One portion of vegetables is equivalent to ½ a cup of lightly cooked vegetables, 1 cup of raw vegetables or 125ml pure vegetable juice.
It is always best to eat fruit and vegetables as fresh as possible as their nutrient and phtyochemical content will deteriorate the longer they are stored. Keep refrigerated and store in the fruit and vegetable compartment. Try to keep fruit and vegetables covered to prevent dehydration and exposure to air and eat within 3-4days.
Fruit and vegetables should be eaten raw if possible as cooking can destroy many of the vitamins, minerals and other nutrients they contain. If you want to cook them, lightly steam, stir fry or boil quickly in a very small amount of water to preserve as many nutrients as possible.
A diet high in nitrites and nitrosamines
Cured meats like bacon, ham and certain sausages are made with a chemical called sodium nitrite that acts as a preservative. When cooked, these nitrites become a potent substance called nitrosamine, which is known to be carcinogenic and increase the risk of stomach cancer. Try to reduce your intake of these foods if possible.
Lack of exercise and obesity
A lack of physical exercise is strongly linked to obesity. Obesity increases the risk of developing breast, endometrial, colon, kidney, oesophagus and gall bladder cancer. Avoiding excess weight gain can lower the risk of developing these cancers. Regular physical activity lowers the risk of developing breast and colon cancer.
Experts recommend that people establish habits of healthy eating and regular physical activity (5 times a week) early in life to prevent overweight and obesity. Walking, swimming, cycling, dancing, golf, yoga, gym or any other form of exercise will all help to improve your fitness level and lower your cancer risk. Those who are already overweight or obese are advised to avoid additional weight gain, and to lose weight through a low-calorie diet and exercise. Even a weight loss of only 5 to 10 percent of total weight can provide health benefits.
To reduce your cancer risk and improve your overall health, here are some basic guidelines to follow:
Eat “real” food
There are so many new foods and products in the shops and they all have shiny and interesting packaging that shout “Buy ME!” Unfortunately, many of these foods are highly processed and refined and have very little nutritional value. They are also often full of additives and preservatives. Fresh, “Real” foods that will go off within a week or so are much better for you as they are full of health-giving and cancer-protective nutrients that help your body to stay healthy and fight off disease Try to eat less processed and refined foods and more foods that are fresh every day. Eat plenty of wholegrains, oats, legumes, soya foods, fruit and vegetables, nuts and seeds, lean meats, chicken, fish, eggs and low fat dairy products every day. Food should be kept as fresh as possible and eaten well before it goes off.
Create a rainbow on your plate
Include plenty of different coloured vegetables and fruit in your diet every day. The deeper the colour, the more antioxidants and phytonutrients (like flavinoids, phenolics, lutein, carotenoids) the fruit or vegetable contains. Eat foods like red cabbage, beetroot, dark green leaves like spinach, rape and kovu, carrots, butternut and pumpkin, mangoes, red/purple plums, kiwi fruit, orange peaches, green melon, pomegranates, oranges, nectarines, berries. Make fresh juices from these fruit and vegetables too! Antioxidants protect your cells from free radicals that can and damage cells cause cancer.
Eat your cruciferous vegetables
Vegetables like broccoli, cauliflower, cabbage and Brusssels sprouts all belong to the cruciferous vegetable family. These super-vegetables contain something called indole-3-carbinol (or I3C), which has amazing anti-cancer properties and has even been shown to prevent the growth of cancer cells. Include these vegetables in your diet on a regular basis for improved cancer protection.
Eat healthy fats
Unsaturated oils are important for good health. Eat moderate amounts (3-6tsp./day) of healthy oils like olives, olive oil, seeds, nuts, avocado pear and other plant oils every. The oils found in cold water fish like salmon, sardines, pilchards, mackerel and trout are also very good for you. Try eating a portion of cold water fish twice a week if you can.
Flax seeds full of omega 3 oils that are known to help boost the immune system. They contain special IP6 fibre that help reduce your absorption of excess dietary iron and are a source of plant-based oestrogens that can help reduce your risk of breast cancer. These tiny brown seeds are difficult for humans to digest so grind or crush them before you eat them to improve your body’s ability to digest and absorb all their goodness. Aim to eat 1-2Tbsp. of ground flax seeds every day. Sprinkle them on cereal, porridge, yoghurt or salads.
Reduce your intake of animal fats by eating small portions of lean red meat, eating more fish and chicken and avoiding processed meats like salami, polony, sausages etc. Choose low fat or fat free dairy products and use butter in moderation. Avoid processed fats like hard margarine, snack foods, pies, pastries and deep fried foods like doughnuts, French fries as these are high in trans fats, which not only increase your risk of developing heart disease but also increase your cancer risk.
Eat soy-based foods
Soya based foods like soya beans, tofu, tempeh, miso and edamame contain plant oestrogens that can help to reduce the risk of breast cancer. They also have other health benefits as they are high in protein and vitamins and minerals and low in fat. Studies have shown that the incidence of breast cancer in countries like Japan, where soya foods are eaten regularly, are much lower than the rest of the world. Tofu and tempeh are available at many Chinese restaurants and take away outlets.
Drink plenty of water
Our bodies are made up of approximately 70% water, and we require water for many of the biochemical processes that take place in our bodies every day. Aim to drink around 6-8 glasses of water a day. There have been reports that plastic bottles are unsafe and release compounds into water that cause cancer, but Cancer Research UK has released a statement saying that no studies have shown this to be true and that plastic bottles are safe and do not cause cancer.
Drink alcohol in moderation
Studies show that excess alcohol consumption increases the risk of mouth, throat, esophagus, larynx, liver, and breast cancer. Experts advise that women drink no more than on alcoholic drink every day and men no more than two drinks every day.
Healthy food preparation and storage
Food is perishable and needs to be handled with care to preserve its nutrients.
- Fruit and vegetables should be bought as fresh as possible.
- Avoid storing them for too long as the vitamins, minerals and other phyto-nutrients start to degrade and break down after picking.
- Refrigerate fruit and vegetables and ensure that they are not exposed to air as this will lead to discolouration and dehydration.
- Eat fruit and vegetables raw if possible or cook very quickly to preserve goodness e.g. steam, boil, stir fry.
- Store oils and nuts and seeds away from direct contact with sunlight as they will go off quickly.
- Store in a cool, dark cupboard and seal well to avoid contact with air, which can make them go rancid.
- Nuts and seeds freeze well. If you are buying in bulk, decant into smaller containers or bags and store in the freezer until needed.
- Grilling or braaing over coals causes the fat on meat to burn, and is releases toxic and possibly carcinogenic compounds. Braaing meat and cooking over a fire is such an integral part of Zimbabwean culture, but use of this form of cooking should be limited, if possible.