Processed meat refers to any meat which has been modified. Meat may be modified to improve its taste or extend the shelf life. Ways to do this include salting, curing, fermentation, and smoking, meats like pork, beef, or poultry. Examples of processed meat products include bacon, ham, hot dogs, sausages and salami.
In 2015 a health warning was issued linking a diet rich in processed meats to an increased chance of developing cancer (notably bowel cancer). This came from the International Agency for Research on Cancer who reviewed over 800 studies. The results showed that those who ate the most processed meat had around a 17 per cent higher risk of developing bowel cancer, compared to those who ate the least. This research was published in The Lancet (“Carcinogenicity of consumption of red and processed meat.”)
A year later, a separate review suggests that a diet rich in processed meat products, for those with asthma, could see the condition become worse over time. This is based on a study of nearly 1,000 French people, according to the BBC. The reason is linked to nitrites, which are added to meat products as a preservative. Nitrites appear to aggravate the airways. With the study, the researchers correlated asthma symptoms (such as breathlessness, wheeze, chest tightness) against the amount of cured meat (ham, sausages or salami) eaten. Subjects in the study who eat four portions a week of processed meat (equivalent to eight slices of ham or four sausages), and who had asthma, experienced the worse symptoms.
The French study, while important, is based on one geographical locale and time point. Moreover correlation does not imply causation and there could be factors other that meat consumption which explain the findings. Prospective studies like this one are useful for spotting links between factors but they cannot, without further evidence, prove that one factor (in this case diet) causes another (as with the current study: asthma symptoms).
Therefore, further studies will need to be run, looking at different populations, to determine if the initial findings can be verified. According to Dr Erika Kennington, who is Head of Research at Asthma U.K.: “Although certain foods can be triggers for allergies in some people, there is no specific dietary advice to manage asthma symptoms generally. For most people with asthma, healthy eating advice is exactly the same as it is for everyone else: follow a balanced diet that includes plenty of fresh and unprocessed food and is low in sugar, salt and saturated fat.”
The new research is published in the journal Thorax, with the research headed “High dietary processed meat intake linked to worsening asthma symptoms.”
