Hunger is the last thing on the mind of a person struggling through a bout of hay fever. Allergy sufferers frequently suffer from reduced appetite, probably as a result of the many unpleasant symptoms that allergies produce. Paradoxically, hunger can be an allergy symptom, but, according to emerging research, it most likely is associated with dietary allergies and food sensitivities instead of respiratory allergens.
According to the National Institutes of Health, the most common causes of increased appetite or hunger include anxiety, diabetes, Graves' disease, hyperthyroidism, hypoglycemia, or low blood sugar, and premenstrual syndrome. The food allergy most associated with hunger is a wheat allergy, also called celiac disease or sprue in its most severe form. According to the National Institutes of Health, decreased hunger and weight loss are common symptoms of celiac disease, but the NIH points out that increased appetite also can occur.
According to Dr. James Braly, an expert in food allergies, food cravings are a common symptom of hidden food intolerances or sensitivities and can be extreme. Braly says that experience in treating patients with food allergies and other addictions shows that strong cravings for the allergic food disappear once the food is eliminated. Nutritionist Dr. Ellen Cutler reports that food cravings, eating disorders such as bulimia and obesity are frequent symptoms of a food allergy or food sensitivity.
According to Dr. Stephen Wangen of the Center for Food Allergies, part of the body's allergic response to food includes the release of antibodies called IgE and IgG. While IgE allergic reactions occur quickly and include respiratory symptoms, Dr. Wangen says that IgG reactions can take several days to develop after eating the allergic food and primarily involve digestive symptoms. According to "Allergy Smarts," an IgG reaction to a food allergy or intolerance causes inflammation of the digestive system and release of ghrelin and exorphins, which are hormones that can increase hunger.
Some research is beginning to show that hormonal imbalances can result from food sensitivity or an allergy, especially a wheat allergy. A 2005 study conducted by Dr. Tommy Jonsson and others found that a cereal-based diet produced resistance to the hormone leptin, which signals the brain with a message of "fullness," reducing hunger. According to a 2009 report in "Science Daily," the Metabolic Research Laboratory of the University of Navarra, Spain, showed that the hormone ghrelin increased appetite and also contributed to increased abdominal fat deposits.