It's important to make the distinction between food intolerance and food allergy because the two reactions, although both uncomfortable, originate in different systems within the body.
A food allergy triggers a reaction from the body's immune system. The body's natural defense mechanisms identify the protein in the food as a dangerous invader or allergen. The body reacts quickly by producing antibodies. Even tiny amounts of the allergen may trigger typical allergic reactions like swelling of the skin, itchiness, or hives.
There are a few foods that are responsible for most of food allergies in adults. While it's possible to be allergic to any food, most allergic reactions occur after eating shellfish, tree nuts, peanuts, or fish.
For some people, a serious allergic reaction may occur when they eat certain types of food. Symptoms may include dizziness or difficulty breathing, and immediate treatment may be necessary. People with serious food allergies usually carry epi-pens for emergency use.
A food intolerance triggers a reaction from the body's digestive system. People who can't break down a certain type of food properly may experience digestive distress. Some examples include occasional bloating or gas, stomach pressure, or irregularity.
There is a significant difference between living with a food intolerance and living with a food allergy. People with food allergies may experience severe reactions to certian foods. In some cases, food allergies are severe enough that being in the same room, inhaling, or touching the food can cause a reaction.
How to manage multiple food intolerances
Before you figure out which foods may be at fault for your digestive discomfort, it can be difficult to remember what you ate, and which foods may have triggered occasional gas, bloating, or irregularity.
Keeping a food diary is an effective way to make a clear connection between digestive problems and a certain food. You may feel uncomfortable at once after eating or the onset of digestive upset may happen hours later. Establishing a pattern is especially helpful if you are working with a healthcare practitioner. A food diary will help you speak confidently about your experiences as they relate to the food you've eaten. If you know that certain foods trigger occasional stomach upset, avoiding them, and continuing to keep a food diary will help clarify the issue.
When away from home, it's a good idea to plan so you can avoid foods that may cause problems. Before eating out, check restaurant menus online to find a few options that you'll enjoy but won't trigger an upset stomach. Many people with multiple food intolerances find that calling the restaurant ahead of time to find out about the menu is helpful.
Supplements with digestive enzymes help support digestion in people with multiple food intolerances. It's common for adults and children to have an intolerance to certain types of food because they don't have the enzymes needed for proper digestion.
Diagnosing food intolerances
While there are exact tests available for celiac disease and lactose intolerance, diagnosis of other food intolerances may involve an exclusion diet. Upon doctor recommendation, a patient that suspects a food intolerance avoids that food and any ingredient or additive that has the food for a period of two weeks to two months.
If their digestive issues subside within that time, they reintroduce the food and pay attention to their body's response. When taking part in an exclusion diet, it's important to completely cut out the food and any ingredients that have the food. If they feel uncomfortable after reintroduction of the food, it may be the culprit.
Some doctors ask their patients to take part in an elimination diet[ii] to help clarify which food causes an unwanted reaction. An elimination diet may involve removing dairy, gluten, soy, eggs, peanuts, shellfish, corn, tree nuts, fish, preservatives, artificial sugars, and artificial dyes from the diet.
After a predetermined amount of time, often several weeks, one food at a time is reintroduced to the diet. If all goes well, another food goes back into the diet a few days later. In many cases, one or more foods cause unpleasant digestive issues. This process helps a doctor figure out which, if any, food sensitivities and intolerance cause occasional stomach upset.
An elimination diet may be difficult to tolerate, especially if it means giving up caffeine or sugar. It may be helpful to create a list of foods that are acceptable during each phase of the diet before beginning such a restrictive food plan.
Signs of food intolerance
People who experience unpleasant side effects after eating a certain food may naturally try to avoid it. Others want to understand what's going on and get a definitive answer about whether they have a food intolerance.
Common signs of food intolerance include occasional nausea, fatigue, digestive discomfort, stomach pressure, bloating, or irregularity. The situation may change with each incident of exposure to the food.
People who have a food intolerance may avoid social situations where there's food, but the bathroom isn't easily accessible, like music festivals or long theater productions. They may also avoid situations where there aren't modern bathroom facilities available like hiking, camping, and boating.
For some, the sudden onset of occasional cramps, gas, bloating, and stomach pressure means that they have difficulty digesting certain foods. For others, feeling exhausted affects day-to-day life, but has no clear cause. In these cases, it's important to consider the possibility of a food intolerance.
While some people experience digestive upset within minutes of eating a certain type of food, others may feel fine for awhile but notice stomach problems later. For example, hypothyroid conditions like Hashimoto's are the result of a gluten intolerance[iii] in some people. About 16% of people with celiac disease experience negative effects in their thyroid function. [iv]For these people, cutting gluten from their diet is a key step towards better overall health.