Food allergies. When an asthma attack is caused by allergens, the culprit is usually dust, molds, pollen and animals. But sometimes food allergies can also cause asthma. Some foods to avoid to reduce asthma symptoms: 1  Nuts. 2  Soy. 3  Shellfish and fish. 4  Wheat. Sulfites.  Dairy 1  products.  Eggs.