Cancer and diet do's and don'ts


Step 1: Understanding the relationship between cancer and food

Epidemiologists who have studied the prevalence of cancer amongst the different populations of the world have found that diet determines 40 percent of all cancers. The incidence of different types of cancer in different regions points to diet being instrumental in the causing of cancer. Studies appear to disprove genetic determinants, as cancer incidence amongst immigrants to a new country quickly takes on the characteristic incidence of those already living there.

Eating the wrong type of food can increase one’s chances of getting cancer by 40 percent. Eating the right kind of food containing cancer-fighting molecules, such as fruit and vegetables, can make a huge difference.

Genetic factors also play a role. It does sometimes happen that healthy young people who get exercise, eat healthily, stay out of the sun, don’t smoke and don’t drink, get cancer. To a certain degree, it remains a mysterious disease, but one, if detected early, that can mostly be sorted out by means of the right medical attention.

Cancer occurs when there is a mutation of the DNA. It is when something goes wrong with the DNA that cancerous cells gain a foothold. Many of the foods we eat that contain anti-oxidants and anti-carcinogenics and other cancer-fighting chemicals, close ranks around our DNA, which prevents cancerous mutations.

Read: Processed foods tied to cancer

Step 2: Adopting new healthy habits

There are many ways in which individuals can lower their cancer risk by changing their habits:

- Stop smoking.

- Don’t drink more than two drinks daily.

- Stay away from known cancer-causing substances, pollutants and chemicals.

- Don’t get sunburnt.

- Visit your doctor if you stay tired, or take too long to recover from an illness.

- Exercise three to four times weekly.

- Lose weight if you are overweight.

- Watch your diet. Certain foodstuffs are anti-carcinogenic, others have antioxidant properties and others are high in fibre. Some foods should be avoided and others need to be consumed in greater quantities.

Read: Food as medicine?

    Step 3: The basic principles of diet in the prevention of cancer

    Major problems of the modern Western diet:

    1. Too much fat. We consume far too many fats, and specifically Omega 6 fatty acids and trans fatty acids, and too little Omega 3 fatty acids. Omega-6-fatty acids are found in fatty foods, margarine, and most importantly, sunflower cooking oil, and trans fatty acids in brick margarine and reheated oil.

    Omega 3 fatty acids, which are good for us and help in the fight against cancer, are contained in cold-pressed olive oil and the much cheaper Canola Oil.

    The diet of the hunter-gatherer resulted in his having a 1/1 ratio of Omega 6/ Omega 3 fatty acids. The ration in the Western countries today is 10/1. It is not difficult to see that this change must have some impact.

    The incidence of cancer, especially breast and prostate cancer, has increased dramatically in the last few years. The former seems to increase dramatically in a population where the per capita fat intake is high.

    2. Too much refined flour products. The problem lies with the foundation of the food pyramid, namely refined flour products, such as white bread and pasta. Furthermore, our bodies do not need to consume sugar, as we can produce our own from carbohydrates.

    Refined foods used to be only available to the very rich, whereas the general population tended to eat more healthy and less expensive wholewheat products. With the advent of the Industrial Revolution, it became easy to refine all wheat, thereby removing much of the nutritional value it contained.

    3. We consume too little anti-carcinogenics. Huge studies have been done in the USA with the help of the so-called Cohort Group of 100 000 volunteers, who are all in some way involved with the medical profession. Professor Walter Willet has also found that the lack of protective factors appears to be more important than excessive harmful factors in the diet.

    Important anti-carcinogenics include:

    - It has been found that the red colourant in tomatoes suppresses the incidence of prostate cancer by up to 50 percent. Tomatoes in all its forms, cooked, raw, pureed in tins or tomato sauce is a powerful anti-oxidant and should be consumed by everyone in vast quantities. It is also cheap and freely available.

    - There are chemicals in garlic and onion that stimulate the production of enzymes that neutralise cancer-producing cells.

    - Fresh fruit and vegetables contain lots of anti-carcinogenics.


    Limit or avoid the following foodstuffs:

    - Animal fats, found in many different types of meat and dairy products.

    - Large quantities of margarine are also unhealthy.

    - Refined flour products are also problematic as is a high consumption of alcohol.

    - High consumption of salt and sugar is also unhealthy.


    Up you intake of the following foodstuffs:

    - Foodstuffs high in B vitamins and folic acid, such as green beans and spinach.

    - Foods containing Omega-3 fatty acids, such as fish (tuna, salmon and mackerel, in particular) and olive oil not only lower cholesterol, but play an important role in combating the damage done by Omega 6 fatty acids.

    - Fresh fruit and vegetables should be eaten regularly, as should wholewheat grain products. In particular, vegetables that have cancer-fighting properties include green leafy vegetables and garlic and onions, both of which produce enzymes that neutralise cancer-producing cells. High consumption of tomatoes is also very beneficial.

    Visit our Cancer Centre for up-to-date information on cancer.

    Read more:

    Colon cancer tied to certain foods

    Foods that can help to prevent cancer

    Reduce cancer by limiting fried foods

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