If you’re one of the millions of Americans suffering from asthma, you might want to rethink your next ham sandwich.
A new study revealed that a high dietary intake of cured and processed meats, such as ham and salami, is associated with worsening asthma symptoms. Published in the journal Thorax, the study found that four or more weekly servings seem to have the greatest impact on symptoms.
“This research extends the deleterious effect of cured meat on health, and the effect of diet on asthma in adults, and provides a novel analytic approach regarding the role of BMI in the diet-asthma association,” the researchers said.
The study was based on 971 adults, with 49 percent of them men. The researchers took data from participants in the French Epidemiological Study on the Genetics and Environment of Asthma. The EGEA has tracked the health of more than 2,000 asthma patients, their close relatives and a comparison group through surveys and exams for more than 20 years.
The researchers used data that was obtained from 2000 to 2013 on the participants’ diets, weight and asthma symptom scores, along with demographic data. Between 2003 and 2007, 42 percent of participants said they had asthma at some point.
To measure dietary intake, the participants were given food frequency questionnaires with 118 items in 46 food groups. Cured meat intake was considered ‘low’ for one or fewer weekly servings, ‘medium’ for one to four weekly servings and ‘high’ for four or more.
The participants said they ate an average of 2.5 servings of cured or processed meat intake a week. By 2013, there were no changes in asthma symptom scores for just over half of the participants.
For one in five participants, or 20 percent, symptoms had worsened. For 27 percent, symptoms improved. Among those who ate one or fewer weekly servings of processed meat, the proportion of those with worsening asthma symptoms was 14 percent.
Among participants eating one to four servings, the proportion was 20 percent. Among those eating four servings or more, the proportion was 22 percent.
After reviewing additional information — including smoking habits, physical activity, age, sex and education — researchers found that those who ate the most cured meats were 76 percent more likely to experience worsening asthma symptoms than those who ate the least.
Obesity has been previously linked to worsening asthma, and it accounted for 14 percent of this association, suggesting that processed meat intake could have its own role in asthma symptoms, the researchers said.
Researchers noted that the study was observational, so no firm conclusions can be drawn about cause and effect. Survey responses relied on memory and symptom scores may have been affected by smoking or COPD, a chronic lung disease that has similar symptoms to asthma.