Are you eating yourself to cancer?

Cancer is quickly becoming one of Kenya’s worst health burdens, with 60 people dying of the disease every day and nearly 30,000 new cases diagnosed annually.

But why is this so? Why has this debilitating disease become so prevalent in the country in the last 10 years?

While there are many causes of the disease — including environmental, physiological and biological — one easily rectifiable Kenyan trend is predisposing tens of thousands of people to attack; and that trend is the changing food choices for a rapidly urbanising population.

Some of the popular foods have been found to either be outrightly carcinogenic, or containing chemicals and additives that can aid the growth of cancerous tumours in the body — by causing cells to divide faster than the normal rate — if over-consumed.

It is, however, difficult to assign a specific risk factor to a particular cancer, according to Ms Anne Ng’ang’a, head of the National Cancer Control Programme. “Usually, it will be an interaction between genetic characteristics, environmental factors and lifestyle,” she explains.

As such, it is almost impossible to get data on the number of people who develop cancer from consumption of a specific food item. “We usually talk about certain risk factors being associated with a cancer, but not causing the cancer,” says Ms Ng’ang’a. “To prove causation you would have to conduct randomised clinical trials.”

Still, if you want to live a long, healthy life, her advice is simple: adopt a healthy lifestyle, exercise regularly, eat a healthy diet rich in natural foods, avoid tobacco use, limit alcohol intake, and visit your doctor for regular cancer screening, especially if you have a family history of cancer. 

Very hot drinks

Yes, we know! Your steaming cup of tea seems like an unlikely candidate in this debate, but the cancer agency of the World Health Organisation, IARC, says those who prefer their tea straight from the pan to the gut could be exposing themselves to great risks. The danger is in the high temperatures — and not the drink itself — which could lead to cancer of the oesophagus.

These warnings are based on studies in China, the Islamic Republic of Iran, Turkey, and South America, where tea is traditionally drunk very hot (at about 70°C). Researchers found that the risk of oesophageal cancer increased with the temperature at which the beverage was drunk.

The proportion of oesophageal cancer cases that may be linked to drinking very hot beverages is, however, not known, but it is worrisome all the same. The phrase ‘very hot beverages’ refers to drinks hotter than 65 degrees Celsius. The temperature scalds and damages delicate tissues in the oesophagus which may in turn lead to out-of-control growth of cells, including malignant ones. 

Unsafe vegetables

The increasing use of pesticides to improve yields and keep pests and insects at bay unfortunately means that the residues of agricultural pesticides can remain in the crops and eventually find themselves on your plate of vegetables, grains, and fish. Of particular risk is a herbicide called glyphosate and the insecticides malathion and diazinon, which are classified as probably carcinogenic to humans.

Glyphosate is a widely used weed-killer and is most popular with farmers because of its low cost and effectiveness. Cell studies have shown abnormal changes to cell DNA when one is exposed to the chemical.

It may cause such cancers as lung, prostate, non-Hodgkin lymphoma (in white blood cells), and rare kidney and pancreatic cancers. Other health effects are DNA and chromosomal damage in human cells. 

Red and processed meat

Most Kenyan weekends, holidays and get-togethers are not complete if meat — roasted, fried, or boiled — is not shared over ugali, kachumbari, and beer. But this ‘nyama-fest’ that Kenyans love is not that safe (do not get us wrong, for meat has health benefits too, such as helping in the production of blood cells).

Research has spawned evidence that shows that red meat increases your risk of colorectal, pancreatic, and prostate cancer. Eating red meat has not yet been established as a cause of cancer, but if the reported associations are proven to be causal, the Global Burden of Disease Project, an independent academic research organisation, has estimated that diets high in red meat could be responsible for 50,000 cancer deaths per year worldwide.

Modern Kenyan breakfasts are increasingly sporting bacon, ham, sausages and a variety of processed meats. Hot dogs are delish for many, but these have been linked to cancer. Processed meat — beef, pork, lamb, goat — is one that has been treated in some way to preserve or flavour it by salting, curing, fermenting, or smoking. Researchers from the WHO found that eating 50 grammes of processed meat every day increases the risk of colorectal cancer by 18 per cent.

That’s the equivalent of about four strips of bacon or one hot dog. According to the Global Burden of Disease Project, about 34,000 cancer deaths per year worldwide are attributable to diets high in processed meat.

The science is simple; meat can contain chemicals that form during processing or cooking, such as N-nitroso compounds and polycyclic aromatic hydrocarbons. Cooking of red or processed meat also produces these compounds, which are known or suspected carcinogens. Types of cancers associated with red meat are colorectal, pancreatic, and prostate, while processed meats cause colon and rectum cancers.

Tobacco

This is probably not news anymore, given the warning messages tobacco products have been associated with. What should worry you is that tobacco causes over 15 types of cancers, essentially in any part of the body. Tobacco products include cigarettes, cigars, and the commonly smoked shisha (users are also exposed to dangerously high levels of the poisonous gas carbon monoxide, which increases risk of lung cancer). These products can either be smoked, snuffed or chewed.

Secondary smokers are not spared either as the smoke has higher concentrations of cancer-causing agents and is more toxic than mainstream smoke. These passive smokers are exposed to smaller particles from the smoke which get into their lungs and the body’s cells more easily. Therefore, they are at risk of the same cancers as active smokers. People who smoke and drink multiply their risk for certain cancers, as tobacco and alcohol work together to damage the cells in the body.

Alcohol makes it easier for the mouth and throat to absorb the cancer-causing chemicals in tobacco. Like alcohol, the more tobacco is used, the higher the risk of cancer. About one million cancer deaths per year globally are due to tobacco smoking.

Chemicals in cigarette smoke damage the DNA and the genes that would have otherwise protected us against cancer. Further, the chemicals make it harder for smokers to neutralise or remove toxins, and can make their immune systems less effective too.

Polycyclic aromatic hydrocarbons (PAH)

Yes, we agree; that’s a mouthful. But it is not foreign. The PAH family of chemicals is found in baked, barbecued or grilled products such as cakes, nyama choma, roasted maize, grilled chicken, and deep-fried foods such as mandazi and French fries, among others.

Those sweet, crunchy darkened portions of cakes you so love are rich in harmful hydrocarbons, formed by the high temperatures during roasting or baking. Such chemicals are also found in tea, roasted peanuts, coffee, refined vegetable oil, cereals, and polluted spinach; and in air contaminated with the substances from such activities as burning of coal, oil, garbage or tobacco. 

Polycyclic aromatic hydrocarbons are a group of over 100 different chemicals that are formed during the incomplete burning of organic materials. They bind themselves onto your DNA, destroying parts of this inherited genetic building block. If left unrepaired, they may cause permanent mutations which may lead to tumours.

They are mostly generated during the grilling or barbecuing of meat, when fat drips from the meat onto hot coals or a heated surface and produces smoke that coats the food with the compounds. They are also introduced by certain methods of preserving meat and other foods, such as smoking. PAH is also known to affect immunity, cause eye cataracts, kidney and liver damage, breathing problems, asthma-like symptoms, lung function abnormalities, and skin inflammation. 

Furan

This is a colourless liquid found in processed foods stored in sealed containers, cans, or jars — such as coffee and ready-to-eat baby food — as they are prepared in closed environments intended to prevent bacterial spread. Before foods are canned they are heated to kill micro-organisms, but during that process, and inadvertently, the carcinogenic substance, furan, is formed.

The volatile molecule is also found in the contents of some food cans or glass jars, and in vacuum-packed foods that are ready to eat. Animals exposed to high doses of furan got cancer, but human studies are yet to be done to prove the link.

Nonetheless, the IARC classifies it as a possible human carcinogen. It is not the furan molecule itself that is associated with cancer, but a substance produced in the liver which is necessary for its metabolism (metabolite). These metabolites may react with your DNA, causing mutations and thus increasing risk of cancer. The risks associated with furan are bile duct and liver cancers.

Aflatoxins

The ugali you so love muching could be slowly killing you as Kenyan maize is known to be contaminated with aflatoxins, a toxic fungi which increases the risk of cancers. The International Agency for Research on Cancer classifies aflatoxin in the highest category of carcinogens. It is also found in nuts, oats and other cereal-derived products, as well as in milk from animals fed on contaminated feeds.

Traditional brews made from grains such as maize (busaa) and sorghum, are also known to be contaminated with aflatoxin. Aflatoxin contamination prevalence of maize in Kenya is estimated at between 16 and 65 per cent, while maize consumption is estimated at 0.3kg per person per day. Further, the rising cost of maize flour means contaminated maize may find itself on shop shelves.

Cells accumulate aflatoxins after prolonged exposure, which then leads to DNA mutations, changing the functions of genes or destroying them and thus raising risk of developing cancers of the liver and the digestive system. 

Pulegone

This is a substance found in mint and used to flavour tea, baked goods, alcoholic beverages, and ice cream. It is also used in oral hygiene products, and as a treatment or insect repellent. Therefore, given the wide range of uses of mint, there is a possibility of exposure to pulegone on a daily basis. Studies in animals — mice and rats — have shown that it causes cancers of the liver and urinary bladder in experimental animals.

Helicobacter pylori

Commonly known as H. Pylori, this little bug that causes stomach and small intestine ulcers is found in unclean water and unwashed vegetables. The bacteria thrives in unhygienic conditions and crowded areas, and normally infects people during childhood, primarily as a result of ingesting food or water contaminated with vomit, saliva or faeces of an infected person. Three in four middle-aged adults (or 75 per cent) in developing countries such as Kenya are infected with the bug, compared to 58 per cent in developed countries. Years of irritation on the stomach by the rod-shaped bacteria can lead to some people developing cancer and stomach inflammation. 

________

RISK FACTORS 

•  Human papillomavirus type — cervical, vulva, penile, and throat

•  Radiation — most cancers

•  Asbestos — respiratory, ovary

•  Wood dust — respiratory

•  Solar/ultraviolet emitting tanning devices — eye, skin

•  Human immunodeficiency virus — Kaposi sarcoma, eye, leukaemia,

•  Contraceptives with oestrogen or progesterone hormones — breast

SIGNS AND SYMPTOMS

                Unexplained weight loss is common with cancers of the pancreas, stomach, oesophagus, or lung.

                Fatigue that doesn’t get better with rest.

                Pain, including persistent headaches or back pain, caused by, especially, brain, bone, colon, rectum, ovary or testicular cancers.

                Skin changes — darker looking skin, yellowish skin and eyes, reddened skin, itching and excessive hair growth.

                Change in bowel habits marked by long-term constipation, diarrhoea, or a change in the size of the stool may be a sign of colon cancer.

                Change in bladder function such as needing to pass urine more or less often than usual, pain when passing urine, and blood in the urine.

                Sores that do not heal in the mouth, skin, penis or vagina.

                White patches inside the mouth or white spots on the tongue which are caused by frequent irritation.

                Unusual bleeding or discharge such as coughing up blood, blood in the stool or urine, abnormal vaginal bleeding or a bloody discharge from the nipple may be a sign of breast cancer.

                Thickening or lump in the breast or other parts of the body.

                Indigestion or trouble swallowing.