Food allergy, food intolerance, food hypersensitivity: the silent villains of illness - includes related articles on anaphylaxis, milk allergy, and food allergy symptoms

Nutrition Health Review, Summer, 1995

Q: There seems to be general agreement on the subject of food reactions. Many foods affect people in various ways. How would you define the various categories?

A: Food allergy is an abnormal immunological reaction in which an individual's immune system overreacts to foods that are ordinarily harmless. The part of a food to which a person reacts is usually a protein and is called an allergen. Reaction may occur minutes or hours after the food is eaten. Because the immune system proliferates in particular areas, one or several organ systems may be affected, such as skin, lips, tongue, nausea, cramps, sneezing, coughing, chest tightness, shortness of breath,,and wheezing may follow. The most dangerous allergic reaction is anaphylaxis (life-threatening respiratory distress). It may affect any body system. Food intolerance is a nonimmune reaction to food or food additives. Examples of food intolerances include reactions- to monosodium glutamate (MSG), tyramine in cheese, caffeine in coffee, sulfites in wine, phenylethylamine in chocolate, or milk and its products in the case of someone who has a genetic lactase deficiency. Food hypersensitivity can be attributed to the ingestion of chemicals added to or sprayed on foods. Herbicides, fungicides, insecticides, natural gas residues, antimicrobials, antibiotics, hormones, artificial flavorings, artificial colorings, texture modifiers, and packaging plastics are examples of food and water contaminants that can set off hypersensitivity reactions in vulnerable individuals. Intentional-food and water contaminants make up a long list (noted in articles that follow). The dividing lines between food allergy, food intolerance, and food hypersensitivity are not always clear, except that food allergy is usually the immune system's reaction to the provocation by a particular food.

Q: How do drugs and the plants from which many medications originate affect foods we eat?

A: Pharmacological reactions to foods often contribute to the discomforts of food intolerance. Caffeine is a significant example. Caffeine is categorized in the drug family of methyl xanthine (also present in the kola nut in West Africa and the cocoa bean in Mexico, and, to a lesser extent, in cola drinks).

Coffee, however, contains more than 300 substances in addition to caffeine. It would be unfair, therefore, to attribute all reactions to drinking large quantities of coffee to caffeine. Coffee is shrouded in a cloud of danger. When it made its first appearance in the American continent, coffee was considered an intoxicant and often its use was suppressed. In some countries throughout Europe, coffee is banned in competitive sports. For some people, reactions to heavy coffee drinking include insomnia, palpitations, headaches, gastrointestinal disturbances; restless leg syndrome, hyperventilation, breathlessness, fatigue, and chest pains. Birth control pills and estrogen replacement therapy have been known to cause deficiencies of vitamins B6 and folic acid. Many foods interfere with drugs, causing interactions that diminish the medication's effectiveness.

Q: There seem to be varying time lapses for a reaction to set in when a vulnerable individual ingests a particular reaction - causing food. How long does it take food to pass through the gastrointestinal tract?

A: The range of transit time is usually 4 to 8 seconds for passage through the esophagus; 1 to 2 hours from the stomach; 2 to 6 hours through the small intestine; 12 to 24 hours through the colon. Transit time of foods that pose problems may vary radically from the norm.

Q: Can an individual who is susceptible to a particular food suffer an allergic reaction from the smell of it?

A: In patients with extreme sensitivity, symptoms may develop after the most minute exposure. Asthmatics are usually vulnerable to this particular phenomenon. Not uncommon are reports that people sensitive to seafood have been stricken by its fumes when served to someone else in the room' A recent news account reported that a woman was exposed to the odor of steaming seafood by a passing waiter and suffered severe breathlessness. She collapsed and died in the hospital several hours later. She was described by her companion as an asthma patient.

Q: What has caused the increase in numbers? Food allergy, intolerance and sensitivity have seldom been a medical problem.

A: Foods and food preparation have changed. More ready-prepared foods are sold today. Modern technology has altered foods considerably. New additives are, becoming major factors in food preparation. The variety of foods available today is endless, increasing our exposure to a larger choice of foods and potential allergy. Also, consider the composition of our population, a diversity that has added food fads, ethnic food customs, and labeling practices. For example, dairy-free creamers are not dairy-free; they contain sodium caseinate, a milk protein. Food processors can,continue to avoid disclosure in many ways.

Q: What facts other than foods themselves increase the severity of food allergies?