Cured meats tied to higher asthma risk
DEAR DOCTOR: I love ham sandwiches — and have one almost every day. I also have asthma and just read that processed meats can increase the risk of asthma. How can this be?
DEAR READER: Meats have been cured — that is, preserved and flavored — since ancient times, largely through salting or smoking. In the United States, these salts have been used to cure meat since 1925 and are highly effective in decreasing the incidence of bacterial disease. However, ingested nitrates and nitrites can form nitrosamines, which are carcinogenic.
Now comes a study, published last year in the journal Thorax, concluding that cured meats like ham increase the risk of asthma. The study enrolled 971 male and female participants from five cities in France. At the beginning of the study, those who consumed more than 4 servings of cured meat per week were more likely to be men, were slightly more likely to smoke, were slightly more obese and had slightly lower educational levels. Those who ate more than 4 servings per week of cured meat were also more likely to be asthmatic and have more severe asthma at the beginning of the study.
After seven years, among those who ate less than 1 serving of cured meat per week, 14 percent reported increased asthma symptoms; among those who ate more than 4 servings of cured meat per week, 22 percent reported increased asthma symptoms. Noting that increased weight is also a factor for worsening asthma symptoms, the researchers adjusted for weight, smoking and educational levels — and still found a correlation between worsening asthma and cured meat.
As for why eating cured meat might worsen asthma, theoretically, nitrites can cause oxidative stress within the lungs and lead to more inflammation within the body, which can worsen asthma. While nitrates and nitrites may worsen asthma, I am not certain that they create asthma.