Adverse reactions to food are common across the population, affecting children and adults alike. These can be classified into two distinct entities -- food allergies and food intolerance. Understanding the similarities and differences between the two is a crucial part of learning how to live with and handle both conditions.
Definition and Processes of Food Allergies
According to "Davidson's Principles and Practice of Medicine," an allergy is defined as an immune-mediated disorder, most commonly due to antibodies against a particular antigen. Davidson notes that up to 20 percent of the population perceive themselves as suffering from food allergy but only 1 to 2 percent of adults and 5 to 7 percent of children have genuine food allergies. This allergen can be anything from pollen to dust to food products. When the body recognizes a particular food product or ingredient as foreign, it activates the body's defense system, triggering a reaction designed to fight off the invasion. The body's hyperreactivity is what people experience as an allergic reaction. Common food allergens include nuts, shellfish, soy and eggs.
Definition and Processes of Food Intolerance
"Davidson's Principles" describe food intolerance as involving adverse reactions to food that are not immune-mediated and result from pharmacological processes like histamine release or monosodium glutamate in foods, metabolic deficiencies like lactose intolerance due to lactase deficiency, or other mechanisms like toxins or chemical contaminants in food. The most common intolerance seen in the general population is lactose intolerance, in which sufferers cannot consume dairy products. Food intolerance is largely dose-related, which distinguishes it from food allergy, which can cause a reaction even with a minute amount of the offending agent.
Symptoms and Diagnosis of Food Allergy
Food allergies can manifest in various forms, ranging from eczema or a runny nose to acute hypersensitivity and anaphylaxis. Identification of the offending agent(s) is of utmost importance in diagnosing and thereby treating the allergy. Although skin prick tests are sometimes done, according to "Kumar and Clark's Clinical Medicine," such measurements have not correlated with symptoms and may be misleading. Instead, keep an accurate log of foods and drinks consumed, and attempt to find correlations and patterns between the symptoms and the foods consumed before the onset of the symptoms.
Symptoms and Diagnosis of Food Intolerance
Food intolerance may manifest in the form of migraines, seen particularly with consumption of cheese, chocolate and wine; irritable bowel syndrome; abdominal bloating; or diarrhea. According to Edward Goljan's "Rapid Review of Biochemistry," the signs and symptoms of lactose intolerance, by far the most common intolerance, result from the inability to digest lactose, or milk sugar. Unabsorbed lactose causes retention of water in the intestines and produces a watery diarrhea. Bacterial degradation of lactose causes abdominal bloating, cramps and flatulence. Food intolerances are also diagnosed by diets of exclusion and careful record keeping.
Treatment of Food Allergy and Intolerance
The easiest and most surefire way to treat both food allergies and food intolerances is to eliminate the offending agent from your diet. If your body is not exposed to the allergen or substance that it cannot tolerate, there will be no adverse reaction. If the substance is accidentally consumed, for some conditions there may be a possibility of improving the symptoms. If the underlying problem is an allergy, an over-the-counter antihistamine may provide some relief. If it is an intolerance, however, this will not make any difference. For lactose-intolerant people, lactase, the missing enzyme, is now available. Symptomatic treatment until the offending agent is eliminated from the body is by and large the best way to handle adverse reactions to food.
References
- "Davidson's Principles and Practice of Medicine"; Nicholas Boon; 2006
- "Kumar and Clark's Clinical Medicine"; Parveen Kumar; 2005
- "Rapid Review of Biochemistry"; John W. Pelley; 2010
