Researchers are finally validating what many of us have known for years: Certain foods just don't agree with some people. Although food allergies are well-recognized because firm diagnoses can be made through the use of blood tests for the presence of IgE antibodies, food sensitivities fall into a gray area. Food sensitivities, such as experiencing unwanted symptoms after eating certain foods, are not as easy to diagnose, but it doesn't mean that they're any less real. And they seem to be on the rise.

Identify Food Sensitivities With an Elimination Diet

The best way to identify a food sensitivity is through the use of an elimination diet, followed by a "challenge" phase in which you re-introduce the food and assess for symptoms. Although this process is certainly more time-consuming than a simple blood test, it's essential to make sure that you accurately identify your particular sensitivities, so as to reduce your risk of eating an overly restrictive diet.

Throughout the process, you will want to keep a food diary, as other factors such as weather, mood, exercise, and menstrual cycles, can all affect your gastrointestinal (GI) functioning and digestive and overall symptoms.

Keep in mind that while food sensitivities can be difficult to identify, but they are rarely life-threatening.

Deciding What Foods to Eliminate

Usually, it's helpful to start with the foods that seem to cause the most trouble for people in general. You can choose to do one food at a time, or do them all at once. These are the top culprits:

1

Dairy Products

For those who are sensitive, dairy products can cause gastrointestinal and/or respiratory symptoms, as well as skin reactions. There are two reasons why this happens:

Many people are lactose intolerant. This means that they lack enough lactase, a digestive enzyme necessary to digest the sugar lactose that's present in dairy products.
Dairy products contain a protein called casein. Casein may be hard to digest and can result in allergy reactions and inflammation within the digestive system.

If you choose to eliminate dairy products, then you would exclude milk, cheese, butter, yogurt, and ice cream. This list includes any product derived from the milk of cows, goats, and sheep.

2

Eggs

Eggs have the notorious distinction of being on the top list of allergy foods for children. However, there are also proteins within eggs that cause unwanted symptoms for some people. Egg whites have more of these proteins, but if you're going to include eggs on your elimination diet, it's best to avoid them completely. Once you've eliminated eggs from your diet for a period of time, you can challenge the egg yolks and egg whites separately to assess for any reactivity.

3

Peanuts

Peanuts are definitely on the list of top food allergens. Even if you don't have an allergic reaction to peanuts, there remains the possibility that you're sensitive to them. Peanuts are not true nuts but are actually classified as legumes. Signs of a peanut sensitivity include respiratory or digestive symptoms.

4

Shellfish

Oysters presented on dishware on a table, overhead view — Jeff Wasserman / Stocksy United

Because shellfish are also on the list of top food allergens for adults, it might be a good idea to include them in your elimination diet. The reactivity is due to proteins found in this group of marine creatures. Examples of shellfish include:

Clams
Crabs
Lobster
Oysters
Scallops
Shrimp

5

Gluten

Variety of breads on wooden surface — rzdeb / E+ / Getty Images

Gluten, a protein found in barley, wheat, and rye, must be totally avoided by individuals who have celiac disease. However, you can have a gluten sensitivity even if you don't have celiac disease. There is some evidence that gluten sensitivity might be the cause of IBS in some individuals. Anecdotally, gluten is suspected to be a factor in a wide variety of health and behavioral problems.

6

Corn

Unfortunately, today's corn is not the corn that our ancestors ate. In research studies, corn has shown up as one of the top foods to contribute to IBS symptoms. The tricky thing about eliminating corn is that it's now a component of so many processed foods in the form of high fructose corn syrup. You'll need to read labels carefully.

7

Soy

Soy Products on wooden surface — Mache Seibel, MD

Soy is on the list of top allergens for children. Anecdotally, many adults attribute IBS symptoms to eating soy-based products. Like corn, soy and its derivatives are now found in many food products. Therefore, just like corn, to avoid soy, you must be very careful about reading food labels.

8

Beef, Pork, and Lamb

Meat on shelf at supermarket — Katrina Wittkamp / Getty Images

Some people report a sensitivity to animal meats. Theoretically, this may be due to the way that most livestock is now reared. Conventionally raised livestock are given corn and soy as primary feed sources, as opposed to grazing on grasses in a pasture. In addition, these animals are also given hormones and antibiotics, all of which have the potential to affect the meat that you're eating.

If you think that these meats are a problem for you, you could try looking for pasture-raised animals and performing a food challenge based on animals that were properly raised and fed. In addition to the fact that you will be eating the meat of healthier animals, there is some speculation that meat from properly raised animals contains components that are good for the health of your gut.

9

Coffee

Many people report that drinking coffee stimulates their bowels. This might be a good thing for some, but for others, certain proteins and chemicals (salicylates) found in coffee seem to contribute to unwanted digestive symptoms.

If you're going to add coffee to the list of foods to avoid on your elimination diet, you will want to wean yourself off slowly to prevent caffeine withdrawal symptoms.

10

High FODMAP Foods

Apples, cherries, and nectarines arranged on wooden surface — Diana Miller Cultura / Getty Images

FODMAPs are certain carbohydrates found in common foods that are fermentable, osmotic, and poorly absorbed, resulting in digestive symptoms for some people. Research studies have found that following a low-FODMAP diet reduces IBS symptoms in approximately 75 percent of IBS patients. If you have IBS, an alternative to following a full elimination diet is to just start with a FODMAPs elimination diet and then conduct a subsequent food challenge.