Be Well: The Lowdown on Food Allergies and Intolerances
Food is our friend, nourishing our bodies and providing the fuel we need to live. Yet sometimes it’s really not all that companionable. You eat or drink something and a short time later you have a headache, your stomach is upset, or worse. What is going on?
While food poisoning can be a culprit, many people have allergies and intolerances to food. More than 50 million people in the United States have food allergies—about 4-6 percent of children and 4 percent of adults—that can be life-threatening, according to the American College of Allergy, Asthma, and Immunology. Another 15-20 percent have intolerances, meaning their bodies have difficulty digesting certain foods.
“In the big scheme of things, it’s not the food causing the problem, it’s your body’s response to the food,” explains Dr. Paul Ratté, a naturopathic doctor in Woodbury and assistant professor of clinical nutrition at Northwestern Health Sciences University. “We need to differentiate between the reactions we see.”
People experience many of the same symptoms with food allergies and food intolerances, but they are different animals. An allergic reaction occurs when the body wrongly thinks a food like peanuts or shellfish is dangerous, triggering your immune system to mount a defense against the allergen. That defense can be mild to moderate, causing hives, vomiting, or dizziness. It also can be life-threatening or deadly when it triggers breathing difficulties or anaphylactic shock.
In contrast, food intolerances involve the digestive system, not the immune system. People who are intolerant to foods like dairy or gluten struggle to digest it. A lactose intolerant person doesn’t have enough of the enzyme lactase to break down lactose, the sugar found dairy. This leads to gas, bloating, cramping, and other digestive issues. Taking lactase pills when eating dairy often will help people digest milk or ice cream without issue.
Those who are sensitive to gluten have trouble digesting the proteins found in grains like wheat, barley, and rye. This is different than celiac disease, an autoimmune disorder that damages the small intestine. Gluten sensitive people experience many of the same symptoms—including headaches, bloating, abdominal pain, and diarrhea or constipation—and feel better when they avoid gluten.
About 90 percent of people with food allergies react to eight main contenders: peanuts, tree nuts, soy, wheat, dairy, eggs, fish, and shellfish. Eating even a small amount of their allergen will cause a reaction. Food intolerances cover more ground. In addition to lactose and gluten, many people experience sensitivity to:
preservatives like sulfites, often found in wine or dried fruit
fermentable oligo saccharides, disaccharides, monosaccharides, and polyols (FODMAPs), short-chain carbohydrates that are prevalent in wheat, dairy, garlic and high-fructose fruits and vegetables
histamines in fermented food like sauerkraut and soy, and cured items like meats
additives like sweeteners or monosodium glutamate (MSG)
Some intolerances are lifelong, while others emerge as people age and their digestive systems slow down.
Discovering bad actors
Determining whether you are allergic to a food is pretty straightforward. An allergist will take your medical history and conduct skin and/or blood tests. After you’re exposed to tiny amounts of dozens of foods, the allergist checks for a reaction on your skin or the presence of immunoglobulin E (IgE) antibodies in your blood. You should completely avoid eating the food you react to.
Uncovering which ingredients cause adverse symptoms—but not allergic reactions—is more challenging, Ratté says. Intolerances can reveal themselves hours or days after you eat a food, making it difficult to pinpoint which ingredient caused your distress.
The most effective way to confirm food intolerances is through an elimination challenge diet, Ratté says. By not eating the most likely suspects, you can more clearly see which foods cause issues as you reintroduce them slowly, one by one, every three to four days. When reintroducing a new food, it’s important to eat it multiple times and see what happens. Do you have an immediate headache, rash, or digestive trouble? Then your body has a sensitivity to it. No reaction means you’re good to go.
Ratté recommends eliminating 15 highly allergenic foods like dairy, wheat, and soy. He’s a fan of the Whole 30 format, but any elimination protocol will work. “You’re more likely to see sensitivities or intolerances, and then we can rule things out,” he says. “I tell people not to eat these foods for 30 days and let’s see how you feel. In my world, it’s guilty until proven innocent.”
Ratté also suggests using a food tracker like MyFitnessPal to log what you eat and how much. Take notes on how your body reacts to different foods and when. Over a few weeks, you should be able to identify which foods are causing problems and eliminate them or significantly reduce your intake. Some people with food intolerances can eat small amounts of a food without causing a reaction.
Some practitioners will have people do blood testing for food intolerances, looking for the presence of immunoglobulin G (IgG) antibodies in about 90 foods. It’s a controversial test because it has many false positives and negatives, often showing high antibodies to foods that never cause a physical reaction, Ratté says. That’s why he prefers food tracking and elimination challenges to zero in on intolerances.
Building a healthy gut
To overcome food sensitivities, try establishing more healthy bacteria in your digestive tract. You can add highly fermented, unpasteurized foods like kimchee and kombucha or take probiotics. This will help establish a healthy microbiome and improve liver and gall bladder function, which both improve digestion, Ratté says.
Also, think broadly about how your lifestyle supports your digestion. “Health is a choice of what you think, how you move, and what you eat,” he adds. “Exercising regularly, like taking a brisk 20 minute walk every day, getting proper sleep, and dealing with stress all will improve gut function.”