Diet causing cancer

Our diets are made up of hundreds of different types of food, containing thousands of nutrients and chemicals. Some of these protect us against cancer, while others increase risk. We all eat different things in different amounts, which confuses the picture even more. As well as that, there are more than 200 types of cancer. So trying to find out how diet affects cancer risk is extremely complicated.

Being overweight

Overweight or being more than about 25% overweight people have an increased risk of bowel cancer and pancreatic cancer and this could be because they tend to have higher insulin levels. Obesity can also increase your risk of

* Oesophageal cancer, kidney cancer and gallbladder cancer

* Breast or uterine (womb) cancer if you are a woman

Scientists are not sure exactly why obesity increases the risk of these cancers. Breast cancer is hormone linked. Its development is affected by amounts of the sex hormones oestrogen and testosterone. Fatty tissue produces an enzyme called 'aromatase'. Aromatase affects the balance between these hormones and this may explain why being obese affects your risk of breast cancer.

Alcohol and cancer

Alcohol can increase your risk of a number of cancers. It increases the risk of mouth cancer, throat cancer which includes pharyngeal cancer, laryngeal cancer and cancer of the foodpipe (oesophagus), liver cancer, breast cancer and bowel cancer. Even moderate alcohol intake increases your risk of cancer.

Foods that might increase risk

Bowel and stomach cancer are more common in people who eat lots of red and processed meat. Red meat includes all fresh, minced and frozen beef, pork, lamb or veal. Processed meats have been preserved in some way other than freezing and include bacon, ham, salami, sausages, spam, corned beef, black pudding, pâté and tinned meat.

Contaminants

Nitrosamines are chemicals found in cured meats annd in very small amounts in beer. Nitrosamines have been shown to be carcinogenic so the amount in foods hascut as much as possiblepoIn brewing, one cause of nitrosamines is a reaction between pollution in the atmosphere and the malted barley that is a main ingredient of the beer.

Smoking and barbecuing foods so that they are slightly burnt on the outside causes chemicals called polycyclic aromatic hydrocarbons to form.urnt on the outside causes chemicals called polycyclic aromatic hydrocarbons to form. These chemicals are known to help cause cancer. So in theory barbecuing or cooking over a high heat could increase the cancer risk of meat and fish.atic hydrocarbons to form. These chemicals are known to help cause cancer. So in Frying and baking meat at high temperatures can create chemicals called heterocyclic amines. These may increase risk of cancer of the bowel.

Rancid Fats

Rancid and oxidized fats contain a wide variety of carcinogens and promoters of cancer, such as fatty acid hydroperoxides, endoperoxides, cholesterol, and free radicals.The colon and digestive tract are continually being exposed to these fat-derived carcinogens. Human breast fluid can also contain high levels of cholesterol epoxide, which is an oxidized form of cholesterol.