>> Scary as it may sound, today, anyone can be on the risk of developing cancer. What if certain dietary and food choices would cut down the risk of the disease? Your Health writers explore on this.
>>NUTRITION: Studies done in Tanzania over several years have shown a significant relationship between red meat consumption and the development of rectal cancer and there have been warning signs
The warning begins with this of taking “very hot beverages.” Did you ever know that gulping tea straight from the pan could harm your gut and expose you to various health risks? This isn’t meant to scare you, and, it isn’t necessarily about your usual hot cup of tea.
The risk of oesophageal cancer increases with the temperature at which a hot beverage is drunk, the International Agency for Research on Cancer (IARC) of the World Health Organisation (WHO) and other researchers have always warned.
Here, the phrase ‘very hot beverage’ refers to a drink hotter than 65 degrees Celsius.
Cancer risk from hot drinks
In East Africa, hot beverage consumption has been linked to cancer of the oesophagus but its risk is still poorly understood in the region, according to researchers who carried out a study titled: ‘Africa’s oesophageal cancer corridor - do hot beverages contribute?’
The study, published in the HSS Public Access Journal, 2015, concluded, “Hot tea consumption, especially milky tea, may be an important and modifiable risk factor for oesophageal cancer in Tanzania.”
But, they noted, contribution of consuming hot tea to the risk needs to be evaluated in this setting, jointly with that of the many risk factors related to this disease.
The researchers said it would be useful to investigate the influence on temperatures of cooler climates in inhabited high altitude areas in Tanzania, Malawi, Kenya’s rift valley, and in the Ethiopian Highlands, and of time of the day and season as there is little indoor heating.
In countries such as China, Turkey, and South America, people traditionally take very hot drinks (up to 70°C) and studies have been carried out in these countries, warning about the same risk.
According to scientists, high temperature usually cause scalds and damages delicate tissues in the gut. This may lead to cells growing out of control, including turning into cancer.
Can foods really cut the risk?
Causes and risk factors for cancer are many and they vary. It’s also difficult to assign a risk factor to a particular cancer according to Dr Heri Tungaraza, an Oncologist at Muhimbili National Hospital (MNH).
“While there are many risk factors for cancer, food is one of the modifiable life aspects that can be adjusted to prevent the disease,’’ says Dr Tungaraza.
And when it comes to the concept of how certain foods could lead to cancer, a medical doctor from MNH, Dr Chris Peterson, believes that most times it may not be about what you have eaten, but how frequently you eat it.
He says, “I tend to take a pragmatic approach along the lines of suggesting that, it’s not what you eat today, it’s what you eat every day that counts. If you love chocolate, reward yourself with the occasional treat-but make sure you don’t invent special occasions every day,’’ he says.
There is strong evidence that alcohol use increases the risk of cancers of the mouth, pharynx, larynx, oesophagus, stomach, bowel, liver and breast.
It’s here that Dr Chris says, “For most cancers, there’s a threshold of alcohol intake above which your risk starts to increase. Sticking to recommended limits (or quitting it if possible) won’t increase your risk of most cancers, except breast cancer.”
He warns further, “Any regular alcohol intake raises a chance of getting breast cancer, so try quitting.”
There have been several warnings about this—and it doesn’t look like news anymore. However, what’s important to note is that tobacco causes over 15 cancers, essentially in any part of the body.
The tobacco products we are talking about here are cigarettes, cigars, and the commonly smoked sheesha (users are also exposed to dangerously high levels of the poisonous gas carbon monoxide, which increases risk of lung cancer). These products can be smoked, sniffed or chewed.
If you are a passive smoker, you are not safe either. Studies show that the smoke from cigarettes has higher concentrations of cancer-causing agents and is more toxic than mainstream smoke.
What happens is that passive smokers are exposed to smaller particles from the smoke, which gets into their lungs and the body’s cells more easily, compared to the active smoker.
Processed and red meat
Studies done in Tanzania over several years have shown a significant relationship between red meat consumption and the development of rectal cancer.
There have been several warnings saying meat should be eaten less frequently or avoided.
Meat prepared at high temperatures and well done produces more heterocyclic amines that can pose the risk of the disease, compared to that prepared at lower temperatures, one study reveals.
Titled: “Pattern and Distribution of Colorectal Cancer in Tanzania: A Retrospective Chart Audit at Two National Hospitals,” quotes reports showing that consumption of 50 grams of processed meat on a daily basis has been shown to increase the risk of rectal cancer by 18 per cent over the lifetime.
But, eating red meat has not yet been established as a cause of cancer, until the reported associations are proven to be causal, reports the Global Burden of Disease Project, an independent academic research organisation.
The types of cancers which have been associated with red meat are: colorectal, pancreatic, and prostate, while processed meats cause colon and rectum cancers.
But there are chemical substances such as Furan—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 the 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. The risks associated with furan are bile duct and liver cancers.
Here, we need to store grains and flour more safely. Without doing this, the exposure to aflatoxins increases as well as the risk of cancer. The ugali you so love munching could be slowly killing you.
Late last year, US-based Center for Disease Control (CDC), carried out tests on 19 blood samples in Tanzania and isolated the most poisonous and cancer-causing substance known as Aflatoxin B1.
That was after a food poison crisis broke out on June 13 last year in Chemba District in Dodoma. It was reported that nine people from the same family in Mwaikisabe Village were affected before it spread out to surrounding areas, including Kondoa District.
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 and sorghum, are also known to be contaminated with aflatoxin
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.
It now matters where you buy the vegetables. A report issued this month by a team of 14 experts from the National Environmental Management Council and Tanzania Bureau of Standards warned that vegetables irrigated by water from Msimabzi Valley in Dar es aSalaam contains hazardous chemicals, some of which could be carcinogenic.
The office of the Chief Government Chemist said it was further investigating the chemical residues in the veges, but a preliminary warning was issued to alert the public about the risk of consuming vegetables grown around the valley.
But on one side, eating vegetables and fruits—of course, those grown in safe conditions, can be used as a means of fighting cancer, although Oncologists such as Dr Tungaraza say some of the aspects of this matter are still debatable.
And the World Health Organization estimates that 14 per cent of cancer deaths related to the food canal are caused by insufficient intake of fruits and vegetables worldwide.
In one of his writings, “You Can Feed the Body Well Enough to Starve Cancer Cells,’’ Dr Tungaraza says, “…some studies are failing to show any clear association between eating fruits and vegetables with cancer risk reduction.”
He suggests, “In my opinion, eating fruits and vegetables for cancer risk reduction is still a good message that I will keep preaching. We should remember that it is estimated that about 30-35 per cent of cancers are due to unhealthy diet.”