Sardine is a type of fish belonging the Sardina genera. Sardines are commonly canned as they are perishable; however, they can be eaten fresh. An allergic reaction to sardines is not rare, and one percent of all individuals worldwide suffer from seafood allergies. The signs and symptoms of an allergic reaction to sardines varies among individuals. If you experience a severe allergic reaction resulting in swelling of the throat and airways, seek immediate medical attention.
Sardine Health Benefits
Sardine has been shown to promote cardiovascular health, weight control, bone health and the prevention of cancer, inflammatory diseases and diabetes. It contains significant amounts of omega-3 fatty acids including EPA and DHA. These fatty acids reduce cholesterol and triglyceride levels, the risk of blood clots, hardening of the arteries and heart attack. Sardines are also an excellent source of vitamin B-12, which helps reduce homocysteine levels and the risk of artherosclerosis. Additionally, omega-3 fatty acids reduce the risk of cancer and inflammatory diseases such as arthritis, asthma, and psoriasis. The high levels of calcium, phosphorous and vitamin D present in sardines promote bone health and prevent osteoporosis.
IgE-Mediated Allergic Respones to Sardine
An allergic reaction to sardine is believed to involve the protein, parvalbumin, which is found in all species of fish. This protein is heat-stable; therefore, eating cooked sardine does not reduce the risk of an allergic reaction. An allergic reaction can be triggered by eating sardine, smelling the vapor while it's being cooked or served, or through skin and mucous membrane contact. The immune system recognizes this protein as foreign and dangerous, and mounts an IgE-mediated immune response. Pro-inflammatory cells, including mast cells and basophils, release histamine and other immune mediators, resulting in the signs and symptoms of an allergic reaction.
Signs and Symptoms of an Allergic Reaction
In addition to the histamine release by mast cells and basophils, canned sardine can also contain high levels of histamine. The histamine in sardine accumulates during the fermentation process, canning process, and as sardine decomposes. The elevated concentration of histamine increases the symptoms and severity of an allergic reaction. An oral allergy syndrome, which involves swelling and itching of the mouth, lips, throat and face, is observed within a few minutes to a few hours of ingesting sardine. Swelling, itching and inflammation of the skin, as well as the appearance of hives and eczema is observed. Histamine is also released in the mouth, throat, upper respiratory tract and larynx resulting in watery, itchy eyes, sneezing, swelling of the airways, tightening of the chest and difficulty breathing. In extreme cases, an individual may experience a life-threatening reaction known as anaphylaxis. Seek immediate medical attention if you experience nausea, diarrhea, fainting, heart palpitations, and breathing difficulties.
Because parvalbumin is conserved in all species of fish, the best way to avoid an allergic reaction is strict avoidance of sardines and all types of seafood. You should also avoid fish oil, and take extra precaution while eating at a restaurant, as cross contamination of food is highly common. Reading the labels of all food products is extremely important as a large number of foods may contain hidden fish. Do not ingest a food or product that does not have an ingredient list, nor should you ingest anything you think may have been in contact with fish.