The physical impact of food allergies, sensitivities and intolerances is growing. Unfortunately, weeding out these problem foods can be tricky.
Wheat vs. Gluten
For those living with food allergies, the risks can vary from an uncomfortable rash to a sudden, life-threatening event. The common culprits responsible for the majority of allergic reactions, known as the “big eight,” are milk, eggs, peanuts, tree nuts, soy, wheat, fish and shellfish. However, it’s wheat that’s been a hot topic in recent years amidst the popularity of wheat-free and gluten-free diets to address health concerns.
“In general, there are two different types of wheat allergy,” says Dr. Timothy Nickel, a board certified allergist and immunologist and a partner at the Allergy Clinic of Tulsa. “The first is an immunoglobulin E mediated reaction involving the classic allergic response, where very small amounts of protein may cause serious and, rarely, life-threatening allergic reactions. Symptoms of this type of allergy occur very quickly after ingestion and include hives, itching, wheezing, flushing and immediate gastrointestinal symptoms of nausea, vomiting and diarrhea.”
Nickel explains that with this type of allergy, patients are generally only allergic to wheat and may tolerate most of the other cereal grains, such as barley and rye. However, approximately 20 percent of these patients may have a coexisting allergy to these other grains. This wheat allergy is generally diagnosed with a skin test, and treatment involves strict avoidance of all wheat proteins – even in small amounts. Patients also require an emergency action plan in case of a reaction, consisting of injectable epinephrine.
“The second type of wheat allergy is a cell-mediated reaction called celiac disease,” says Nickel. “This reaction is more delayed and is actually caused by an allergy to the alcohol-soluble fraction of the wheat protein called gluten. Because of the delayed nature of this reaction, patients may not always associate their symptoms with wheat intake, as this is fairly ubiquitous in the diet. This protein is also found in other grains, such as barley and rye. Therefore, patients with celiac disease must also avoid many of these other grains unlike those with wheat allergy.”
With celiac disease, the allergic reaction occurs in the small intestine, and the resulting inflammation causes symptoms like abdominal pain, cramping, chronic diarrhea (in half the cases), fatigue, joint pain and sometimes a chronic blistering skin rash. Due to the malabsorption of food nutrients, weight loss and nutritional deficiencies such as anemia can follow.
“Celiac disease is generally diagnosed by a blood test or endoscopic biopsy of the small bowel showing villous atrophy,” says Nickel.
According to the Celiac Disease Foundation, it’s estimated that celiac disease affects one in 100 people worldwide and that 2.5 million Americans are undiagnosed and are at risk for long-term health complications.
“As people become aware of celiac disease and with the increase of screening by primary care providers and gastroenterologists, the diagnosis and prevalence of celiac disease has definitely increased over the past couple of years, but not as much as the gluten-free market,” says Dr. Camilla Fraga-Lovejoy, a pediatric gastroenterologist with OU Physicians in Oklahoma City. “Most people who seek a gluten-free diet do not have celiac disease but are trying different food eliminations in an attempt to improve different symptoms. Those patients may have non-celiac gluten sensitivity and have improved symptoms with either decreasing the amount of gluten ingested or gluten elimination.”
Fraga-Lovejoy says that individuals can have a non-celiac gluten sensitivity that’s characterized by intestinal and extra-intestinal symptoms.
“Unfortunately, some of the symptoms of celiac disease and non-celiac gluten sensitivity are similar to irritable bowel syndrome (IBS), and lots of patients have this diagnosis,” she says. “It’s important to keep in mind that different dietary changes have been used in the treatment of IBS patients, and gluten elimination is only one of them. Not every patient will have the same results, as is opposite of patients with celiac disease that need a gluten-free diet for life.”
Fraga-Lovejoy emphasizes that it’s important for patients to seek medical advice to rule out celiac disease before starting a gluten-free diet.
“Celiac disease has lifetime implications and possible complications if not treated, and it will be harder to identify this disease if the patient is already on treatment for it [with a gluten-free diet],” she says. “Patients on a gluten-free diet should also be followed by a dietitian to make sure all recommended nutrients are met on this diet.”
Most often occurring in the southern United States, the alpha-gal allergy is a relatively unknown allergy that’s increasing in prevalence and causing its sufferers to ban red meat from their diet. Discovered in 2009 by a research team at the University of Virginia Health System, the alpha-gal allergy is of special interest due to its delayed reaction.
“This allergy results in anaphylaxis several hours after ingesting beef, pork or other mammalian meats, and many times presents as anaphylaxis in the middle of the night,” says Nickel. “Patients often have multiple trips to the emergency room for generalized itching, hives, swelling of the throat and tongue, wheezing and shortness of breath. Because of the delayed nature, this diagnosis is often missed, resulting in multiple trips to the emergency room with, many times, life-threatening reactions. This delay in presentation is likely related to the fact that our immune system does not recognize this allergen until it is ‘unpackaged’ by our liver several hours later.”
At this time, the current cause of this allergy is thought to be the result of a bite from the Lone Star tick.
While not an allergy, a common condition that has gained attention and also sparked the creation of specialty food products is lactose intolerance. Stroll through any local grocery store, and you can find lactose-free milk, ice cream, yogurt, cheese and much more.
“Lactose intolerance is a very common problem in the United States, affecting up to 20 percent of the population, but is particularly common in certain ethnic groups,” says Nickel. “It’s caused by a deficiency of the enzyme that breaks down the disaccharide lactose present in milk. Normally, ingested lactose is broken down in the small intestine to its component sugars, glucose and galactose, by an enzyme called lactase. These monosaccharides are then absorbed by specific transporters. If there is a deficiency of lactase, then the lactose passes through to the colon, where colonic bacteria break it down, producing hydrogen gas in the process. This, in turn, contributes to the clinical symptoms of lactose intolerance, which include diarrhea, abdominal pain and flatulence after ingestion of milk-containing products.”
Nickel adds that the deficiency can be part of a person’s genetic makeup or can also occur in the setting of a gastrointestinal infection. However, he explains that most infectious causes of diarrhea will cause a temporary lactase deficiency that usually resolves once the infection is cleared.
“It’s important to differentiate lactose intolerance to a milk allergy,” says Fraga-Lovejoy. “Patients with lactose intolerance may be able to tolerate small amounts of lactose in their diet without symptoms, while patients with a milk allergy need to have a strict avoidance of dairy products.”
She also points out that a different diagnosis affecting infants is called milk protein intolerance, which presents a broad range of symptoms, including irritability, vomiting, poor weight gain and blood in stools.
“Symptoms improve with a change from a milk-based formula to specialized preparation, or if breastfeeding, strict avoidance of dairy by the mom,” says Fraga-Lovejoy. “Most patients affected by this condition will outgrow it and be able to tolerate milk by one year of age.”