What is it about food that causes cancer?

Exposures that can lead to cancer are called carcinogens.Some of these carcinogens may cause cancer after prolonged exposure. We explore how one can be at risk and the risk factors and how to beat them.

Monday May 19 2014


By Sandra Janet Birungi

For a long time, cancer was one of those diseases associated with people living in developed countries, but this trend is fast changing as many people in the so-called third world countries are fast becoming victims.

According to Timothy R. Rebbeck, of African Organization for Research and Training in Cancer (AORTIC), cancer is increasingly becoming a problem in Africa due to change, in among other things, diet and lifestyle.

“Increases in life expectancy, changes in diet and lifestyle, and lower burden of communicable diseases promise to increase the cancer burden in Africa over the coming years,” he writes in the foreword of Cancer in Africa.

The World Health Organisation recently announced that cancer will overtake heart disease as the number killer of human beings. Scientists believe that around 80 per cent of cancer is determined by our lifestyle choices.

One interesting question remains unaswered, how has the average diet around the world deteriorated to bring about this higher cancer rate? Read on to find out how.

Anything can cause cancer or can be carcinogenic. These range from drugs to toxins and foods although for them to cause cancer, it is over a long period of time, Dr Fred Okuku, an oncologist at Mulago Cancer Institute says: “Some cancers are slow in developing.

For example cervical cancer can take up to 10 years before symptoms begin manifesting,” he explains. This means if consumed, these carcinogens can take a long time before causing the cancer.


Dietician, Mr Jamiru Mpiima explaining food related carcinogens said one of the major causes of cancer in foods is artificial fertilisation of the foods, right from the garden to the time of consumption. “All foods are cancer free. However, how these foods are treated for example in the garden when they are growing and storage after harvesting can cause them to be carcinogenic,” he says.

Food in storage
Afflatoxins B1: These are produced by fungus formed by stored grains for example maize, nuts, peanut butter, sorghum, millet and ground nuts.

Dr Okuku says for the fungus to develop, there has to be a wet or moist environment and it is caused when cereals are not well-dried. “Afflatoxins are sometimes referred to as mould and form due to poor storage,” Mpiima adds.

Ugandans are exposed to afflatoxins mostly and people should be on the lookout according to Dr Okuku. “You see in some shops where they make groundnut paste, they remove the small groundnuts which people cannot buy and squash them for the paste and groundnut sauce.

These are usually not well kept and increase chances of taking in these toxins unknowingly. But, if you eat groundnuts which already have the fungus, you will have a bitter taste.”

Pesticides: These are commonly used to eradicate pests both in the gardens and during storage after harvesting. According to Fredrick Kizito, a nutritionist, when used, foods end up storing these pesticides which in turn end up being carcinogenic to the consumer after a certain period of time.

During preparation
Acryclamide: This component is formed in fried or over heated carbohydrate foods for example potato chips and also found in over re-used cooking oil. “Re-used oil can end up being carcinogenic depending on how many times it has been re-used. Whereas re-using oil three times is okay, exceeding that could cause it to change colour and become darker, a sign that it is dangerous” Mpiima cautions.

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