A lot of people think that any smoked food has been actually exposed to smoke! But this is not true! Rather, a chemical called liquid smoke is used to flavor the meat for example. This liquid smoke contains dangerous carcinogens chemicals.
Besides smoking, the process of curing meat (bacon, ham, sausages) also involves treating it with a variety of additives and preservatives, which are a reason for cancer development.
As well as nitrites and nitrates, smoked foods are often incredibly high in ordinary salt. They can sometimes contain up to 50 times more salt than a unsmoked version.
The 2007 report, issued by the World Cancer Research Fund, has involved hundreds of experts who have reviewed all the evidence we have to date about the link between food, nutrition, weight gain, overweight and physical activity and the risk of cancer.
According to that report and considering all the research they made the following recommendations:
- There is evidence of a convincing or probable causal link between certain foods and a reduced risk of some cancers including: foods containing dietary fibre, vegetables and fruits, milk, calcium supplements (which protect against colorectal cancer) and selenium supplements (which protect against prostate cancer).
- The following can increase the risk of cancer: alcoholic drinks (they say that evidence that alcoholic drinks are a cause of particular cancers has strengthened), processed meats (meats preserved by smoking, salting, or curing) which includes bacon, ham and salami (which are linked to colorectal cancer), a diet very high in calcium, salt and salty foods, beta-carotene supplements (high doses increase risk of lung cancer in smokers).
- For other factors, there is limited evidence that the link is ‘causal’. For these, the researchers have decided that the evidence is so limited that no conclusions can be drawn. These include fish and food containing vitamin D and colorectal cancer, smoked foods and stomach cancer, milk for bladder cancer, total fat intake for lung cancer or post-menopausal breast cancer, foods containing animal fat and colorectal cancer; and butter and lung cancer.
- For some factors, the researchers have concluded that an effect on risk is unlikely. With coffee for example the researchers say “it is unlikely that coffee has a substantial effect on the risk of cancer either of the pancreas or of the kidney”.
- They concluded that there is convincing evidence that physical activity protects against colon cancer, and evidence that it probably protects against post-menopausal breast cancer and cancer of the endometrium. There is limited evidence that exercise offers protection against pre-menopausal breast cancer, cancers of the lung and pancreas. They also conclude that since physical activity protects against overweight, weight gain and obesity, that it also then “protects against cancers for which the risk is increased by these factors”. They say that “the evidence is consistent with the message that the more physically active people are, the better”.
- When considering the evidence around body weight, the panel concluded that “body fatness” and “abdominal fatness” increase the risk of cancer (various types including oesophagus, pancreas, breast, kidney, colorectal, kidney, gall bladder). They say that the evidence that “body fatness is a cause of cancers of various sites” is more impressive now than it was in the mid-1990s.