Photo credit: Gil Kanat
If you spend much time on the Internet, or reading certain tabloid newspapers, you will probably be aware of the plethora of foods that can supposedly ‘give you cancer’. But how much truth is there to these claims? I have trawled the web to find the truth about the carcinogens (cancer-causing stuff) in your kitchen.
“Canned tomatoes cause cancer!”
Chopped tomatoes are a staple student food, but do they cause cancer? It is actually not the tomatoes themselves that have been linked to cancer, but a compound used in the lining of the cans: bisphenol-A (BPA). Also found in many other food containers, BPA – used to harden plastic – is said to migrate into the food, where it enters the body and contributes to cancer, as well as other illnesses like type II diabetes.
It has been confirmed that BPA is indeed used in many food containers, and that it can have harmful effects in high quantities. Studies appearing to show the link between BPA intake and tumours were conducted in rats, but minimal human studies confirm these results. However, one 2014 study has suggested there may be a link between breast cancer and BPA, as it disrupts genes protecting against tumour growth in human mammary gland cells. Despite this, the Food and Drink Association (FDA) of America has found the current levels of BPA in food to have no significant effects on health, in spite of numerous studies and reviews.
Most products designed for infants are now BPA-free, and it is recommended that consumers check whether their plastic containers are microwavable before putting packaged food in the microwave, to minimise their intake.
“A high-sugar diet causes tumours to grow faster!”
One of the greatest myths surrounding cancer treatment is that you can ‘starve’, and even shrink, a tumour by limiting your sugar intake. This is based on the fact that cells require glucose, found in sugars, to grow and divide. Tumour cells grow and divide faster than regular cells, meaning they respire more glucose and therefore require more sugar.
However, blood sugar levels are carefully controlled by hormones such as insulin. Cells will absorb the sugar that they require, either directly from metabolism or by converting stored fat and protein into an energy source. Excess sugar will be converted to fat and stored. This means that eating more/less sugar doesn’t directly affect tumour growth, as no matter how much you eat, your blood sugar levels will remain regulated.
Short-term sugar intake should not be confused with long-term sugar intake effects – as a long-term overconsumption of sugar has been linked to increased risk of illnesses, and susceptibility to cancer.
“Red meat causes cancer!”
Red and processed meats include sausages, bacon, beef, ham and lamb – but not poultry or fish – and the scientific community has known that they are linked to cancer for some time. Various sources claim that sugars in red meat, and nitrates added to processed meat, cause cancer.
A sugar found in beef, pork and lamb called Neu5Gc is produced naturally in the bodies of most mammals, but not humans – in whom it seems to invoke an immune response. This explains why other mammals can be carnivorous without any ill effects. In a scientific study, mice were genetically modified to not produce Neu5Gc naturally, and fed the sugar in their diets. The incidence of colorectal tumours in these mice was five times higher than that in the control group, and human trials have consistently shown similar, smaller risks.
Sodium nitrate is a compound that can form known carcinogens called nitrosamines when added to cured meats as a preservative. The presence of sodium nitrate and nitrosamines in meat has been linked to an increase in liver cancers and diseases – with bacon especially susceptible due to the high temperatures during frying. The industry has now taken steps to reduce nitrosamine content in meats, adding ascorbic acid, which has been proven to reduce formation of nitrosamines. It is calculated that non-smokers are now exposed to around 0.1mg of nitrosamines per day (as opposed to 1mg, two decades ago), with smokers being exposed to up to 17mg!
Experts recommend healthy adults eat no more than 70g of red/processed meats per day and add more vegetables to their diets to lower their risk of bowel cancers. They can do this by exchanging red meat for fish and poultry and eating their greens! Also, asking for your steak to be cooked medium rare can reduce the number of carcinogens produced during frying.
As with almost everything, moderation is the key to health – a conclusion that doesn’t give the scaremongers much of a headline. Any carcinogen you find in food is probably found somewhere else in more dangerous quantities! Although, to be truthful, I will be buying cartons of chopped tomatoes and cutting down on sausages from now on…