A concerning new study has bad news if you’re a bad fan of eating processed meat. Although the medical community has long preached about the dangers of consuming too much of the stuff, a new study claims that in addition to risks such as heart disease and other health problems, processed meat can also make asthma symptoms much worse.

Scientists think that a preservative called nitrite may be too blame. This preservative is most commonly found in meats like sausages and salami, and it can irritate the airways, although more research will be need to prove this link, according to a BMJ statement.

The threshold appears to be about four portions a week: anything other that puts a person at risk. The study is based on an examination of 1,000 French people.

It’s just another lesson that people should be eating a healthy and varied diet and avoid excess quantities of any one type of food, researchers say.

The statement notes: “Dietary intake was measured using food frequency questionnaires encompassing 118 items in 46 food groups. Cured meat intake (ham, sausage, salami) was classified as low for 1 or fewer weekly servings; medium for 1-4 weekly servings; and high for 4 or more. Asthma symptoms, such as difficulty breathing, chest tightness, and shortness of breath in the preceding 12 months, were scored from 0 to 5 (asthma symptom score). Information was also gathered on other potentially influential factors, such as smoking, regular physical activity, age, sex, and educational attainment.

“Between 2003 and 2007, 42% of the participants said they had had asthma at some point, and around half (51%) had never smoked. Just over a third (35%) were overweight, while nearly one in 10 (9%) were obese. Participants said they ate an average of 2.5 servings of cured/processed meat intake a week. By 2011-13, when the next checks were made, there had been no change in asthma symptom score for just over half the participants (53%; 513). In one in five (20%) symptoms had worsened and in around one in four (27%) symptoms had improved.”