Food allergies increasing

More than 12 million Americans suffer from food allergies. Young children make up the highest percentage by age. About one in 17 children under the age of 3 (5.6 percent of that age group) are dealing with a food allergy. Children aged 1 to 18 represent about 4 percent of cases and adults represent a slightly lower 3.7 percent of cases, according to the Federal Register.

While no cure has been officially found, there is new hope with current research that cures will be found in the near future. Duke University, for instance, is having good results with therapies to eliminate peanut allergies. And, luckily for many, most milk, egg, soy and wheat allergies are outgrown with age.

As a dietitian, I am seeing more and more clients trying to manage a food allergy … and it seems there is more to the story than just a higher diagnostic rate. There actually seems to be an increasing number of individuals developing food allergies. The CDC reports food or digestive allergy increased 18 percent among young people between 1997 and 2007. And, between 1997 and 2002, childhood peanut allergies doubled.

Theories about why food allergies are on the rise include (but are not limited to): (1) genetic susceptibility; (2) the "hygiene hypothesis"(overuse of antibiotics, vaccinations and antibacterial cleaners leaves our immune systems open to attack other perceived toxins, such as foods); (3) a lack of vitamin D, which plays a role in the immune system; (4) an imbalance of omega-3 fatty acids to omega-6 fatty acids; (5) and, the way foods are heavily processed.

Food allergies occur when the body mistakenly identifies a particular food as a health threat. Unlike a food intolerance which causes a digestive response, an allergy involves a complex immune response. Ranging from mild to life-threatening, the severity of a food allergy differs depending on the individual. For some, a minute amount of food ingested or inhaled (perhaps if a child smelled a nut) can cause a reaction — even anaphylaxis (multi-factorial body response that can be fatal). For others, it takes a larger volume of allergenic food for a reaction.

Food allergy causes about 30,000 ER admits and 150 deaths annually, according to the FDA. Peanut and tree nut allergy represent the leading causes of fatal and near-fatal allergenic reactions. And, although there are more than 160 foods that can cause an allergic reaction in humans, the top eight allergenic foods include peanuts, milk, eggs, tree nuts, wheat, soy, fish and shellfish. The top eight cause about 90 percent of reactions.

Sensitive individuals may react with hives or an eczema flare from skin contact. In others, eating an allergen could trigger runny nose, coughing, wheezing, cramps, diarrhea, nausea, vomiting, a drop in blood pressure or a change in heart rate. If someone has asthma, it increases the risk of a severe response.

Although there are different types of immunological responses, one of the most common causes the body to produce antibodies to attack the allergenic food protein. These types of allergies are also called immediate onset, type 1 hypersensitivity or IgE-mediated food allergy. They cause symptoms within seconds or up to a few hours after eating an allergenic food. These allergies can be diagnosed with the usual medical tests such as skin-prick test or RAST blood test or via an elimination diet (where the potential food is avoided for 1-2 weeks and then re-introduced to determine if a reaction occurs). This type of food allergy is often inherited.

One type of immediate onset food allergy is Oral Allergy Syndrome (OAS). This condition is linked to the pollen on certain raw fruits and vegetables. Itching, burning, tingling and sometimes swelling of the mouth, lips, tongue and throat can occur. In severe cases, it is possible to have an anaphylactic reaction. Common foods implicated with OAS include: apples, almonds, apricots, bananas, carrots, cherries, cucumbers, hazelnuts, kiwis, melons, parsnips, peaches, plums, potatoes, sunflower seeds, tomatoes, various spices and zucchini. For the estimated 36 million people with ragweed allergies, for instance, it is important to be aware about OAS.

In the "delayed onset" or "non-IgE-mediated food allergy," delayed onset of symptoms occurs after a food is eaten (usually 4 to 24 hours). While there are several types of this allergy, symptoms often exist in the first few months of life (infancy) and most are outgrown in one to three years. An infant may refuse food, have failure to thrive, seem colicy, pull legs up or have reflux, diarrhea or blood in the stools. Diagnosis is achieved with an elimination diet. If an infant is breastfed, the mother would need to eliminate trigger foods from her diet (or use a hypoallergenic or amino acid-based formula). Elimination of milk products is usually done first. Since at least half of infants with a milk allergy are also usually allergic to soy, it may be recommended to a nursing mother to avoid both milk and soy.

Other types of food hypersensitivities (allergies and intolerances) exist and involve varying responses from the immune and/or digestive system. Several GI disorders have been linked with food hypersensitivities, including irritable bowel syndrome, eosinophilic esophagitis and celiac disease. Additionally, other diseases and conditions, including fibromyalgia, atopic dermatitis, migraines and even depression may have connections with how our bodies respond to certain foods.