If there are bacon lovers in your family, you may want to limit their intake of fatty, cured meats of this kind to less than four portions each week, especially if they have asthma. That’s because recent findings, published in the journal Thorax, show that nitrite, a preservative found in processed meats, may also aggravate the airways of many people with lung problems and make it harder for them to breathe, the BBC reports.

Asthma is a chronic health condition that inflames, narrows and swells the airways and causes the body to produce excess mucus. Individuals with this illness suffer from wheezing, chest tightness, coughing, shortness of breath and, sometimes, life-threatening asthma attacks. In the United States, more than 25 million people are known to have asthma, which can be prompted by exercise, allergies, environmental pollutants, obesity, stress and many other triggers.

For the study, researchers interviewed nearly 1,000 French people who participated in a survey about food and health from 2003 to 2013. Almost half of these individuals had asthma; the other half, used as a control group, had no history of the condition. Specifically, scientists asked those in the study about their experiences with asthma symptoms, including breathlessness, wheezing and tightness in the chest, as well as their intake each week of cured meats. (Researchers defined one portion as two slices of ham, one sausage or two slices of salami.)

After controlling for factors that could make asthma symptoms worse, such as obesity, researchers found that people with asthma who said they consumed more than four portions of cured meat in a week experienced the largest deterioration in their asthma symptoms by the end of the study compared with those who ate little or no processed meats. 

But study authors stressed that the findings merely established a correlation—not a direct link—between the two and that much more research is needed to solidify the hypothesis. 

“Although certain foods can be triggers for allergies in some people, there is no specific dietary advice to manage asthma symptoms generally,” wrote Erika Kennington, PhD, head of research at Asthma UK, in a comment on the study. “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 fish and unprocessed foods low in sugar, salt and saturated fat.”

Previous studies linked eating processed meats with an increased risk of cancer, so study authors suggested people eat no more than 70 grams (about three ounces) of red and processed meat each day for good health, no matter their asthma history.

Click here to learn more about how eating processed meats can endanger your health.