The Top 10 Most Common Food Intolerances That Could Be Triggering Your Symptoms

1. Gluten-containing grains: wheat, rye, barley

Gluten, the protein that’s found in grains like wheat, rye, and barley, is probably one of the most common sensitivities that I see. If you do a little research, you may discover that according to estimates, approximately 18 million Americans have a “gluten sensitivity.”

Is gluten intolerance real?

Not everyone agrees yet, but an increasing number of doctors and scientists are saying yes. One trial (1) published in Clinical Gastroenterology and Hepatology studied people who thought gluten was causing them digestive problems. The gold standard for research is something called a randomized, double-blind, placebo-controlled, crossover trial, and gluten was put to this rigorous test.

For one week, participants were given either a small amount of gluten or a placeo pill of rice starch. After only one week, those who were taking the gluten pills reported a significant increase in symptoms compared to those who took gluten-free placebo pills.

Another recent randomized control trial shared similar findings. (2) These studies are good evidence that some people do experience uncomfortable side effects after eating gluten. More research is ongoing, and I expect that as the concept of gluten intolerance continues to gain credence, we will see even more reputable research legitimizing this condition.

Is gluten intolerance an autoimmune condition?

To understand gluten intolerance, we need to understand autoimmune conditions. Many people think when we talk about gluten intolerance we are referring to the autoimmune condition celiac disease. Yes, celiac is an autoimmune disease, but it is the extreme end of a broader gluten-intolerance spectrum. (3)

You can be on the autoimmune-inflammation spectrum without having celiac disease, and that can result in gluten intolerance, or what doctors sometimes call non-celiac gluten sensitivity (NCGS). You may not have tests that come back saying you have an autoimmune disease, but I believe that gluten reactivity is a warning that you could eventually be headed in that direction if you don’t change your diet and health habits.

What are the symptoms of gluten intolerance?

People in the study experienced:

• abdominal bloating
• ulcers
• intestinal pain

Because your gut is your “second brain,” people with gluten intolerance can also experience:

• brain fog
• depression
• anxiety
• fatigue

If you believe you might have a sensitivity to gluten, there are some tests you can consider.

You can get tested for celiac disease, but assessing gluten tolerance is a little more difficult. Mention gluten, and a conventional doctor will likely get a simple alpha gliadin lab. If it comes back negative, you are told you don’t have celiac disease. However, not everyone with celiac disease has a positive alpha gliadin test. There are more tests that can be done. A functional medicine doctor can also perform even more tests to assess gluten reactivity. Alpha gliadin and the common celiac lab Transglutaminase 2 are just two pieces of about a 24-piece puzzle.

On top of all that, some people react to other aspects of wheat gluten – in fact, there are about 24 different qualities in wheat that can cause reactivity. More comprehensive labs could be incredibly helpful for someone who needs motivation to eliminate some or all grains, or for someone who has reintroduced grains into their diet but is still unsure whether grains are problematic for them.

Gluten Cross-Reactive Labs:

Yet another layer to the problem of gluten intolerance is cross-reactivity. This is when foods that do not contain gluten are “tagged” with gluten antibodies, so that the body reacts to them as if they are gluten, often due to a similar molecular structure. Like a case of mistaken identity this case of mistaken identity can wreak havoc on the person who has gone gluten-free but still has symptoms. Some cross-reactive foods may include:

• gluten-free grains
• milk/dairy products
• soy
• coffee
• chocolate
• eggs

2. Gluten-free grains: corn, rice, buckwheat

Those who choose to avoid gluten but are still having symptoms may not realize that they are grain-intolerant, even when those grains are gluten-free. If this sounds like you, then know that you could have a sensitivity to any particular grain, or all grains. Or, your problem might be cross-reactivity, in which the proteins in grains such as rice and corn can be similar enough in structure to gluten that the body mistakes them and reacts as if they were gluten. This is called molecular mimicry and is sort of like a case of mistaken identity. Many of my patients have sensitivities to some gluten-free grains, although not all.

3. Nightshades

A plant group that consists of tomatoes, peppers, potatoes, eggplant, goji berries, and some spices containing alkaloids, which can be inflammatory for some people.

4. Alcohol

Regular consumption of alcohol can potentially negatively influence almost every system in your body. For the gastrointestinal system in particular, alcohol can be a trigger for leaky gut syndrome and gut inflammation in some people.

5. Sugar

Obvious, right? But do you know why? Sugar is the favorite food of more pathogenic gut bacteria that can cause many gastrointestinal problems, so when you eat sugar, you are feeding the bad guys so they can crowd out the good guys that do nice things for you. An imbalance of bacteria (4) in your gut can also lead to negative effects on your body’s metabolism and immune responses, and overgrowth of bad (sugar-loving) bacteria can also cause inflammation, which can eventually lead to an autoimmune-inflammatory response. Don’t think artificial sweeteners are the answer, though – research shows that they also decrease (5) the good bacteria in the gut, which could also cause glucose intolerance and lead to diabetes.

6. Legumes

Legumes include all types of beans (kidney, garbanzo, black, fava,) lentils, peanuts, edamame, and soy products (tofu, miso.) Many of these foods are staples for people who are trying to eat more plant-based meals, but the lectins and phytate proteins of legumes can be hard for some people to digest. The carbohydrates are also yummy food for your gut bacteria, and when they consume them, they release gas, which means you get gas and the accompanying bloating and discomfort.

Even if you don’t get gas from legumes, they could cause undue stress to your gastrointestinal and immune system due to those lectins and phytates. Peanuts might also contain aflatoxin (toxins produced by a mold), while soy has phytoestrogens, which can interfere with healthy hormone balance. Of all the legumes I have found that soy tends to be the most likely to cause problems for people.

7. Eggs

The incredible egg has many nutrients, mainly in the yolk, but that doesn’t mean it isn’t problematic for some. In my experience, it is actually the egg white that is typically more immunoreactive for people. The protein in the white, albumin, could pass through the intestinal lining if you have leaky gut syndrome, contributing to inflammation. The yolks are generally better tolerated, although it’s important to note that some people can’t handle the yolk, either.

8. FODMAPS

This strange sounding acronym stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. In short: fermentable sugars. These short-chain sugars are contained in many different foods and are not fully digested in the gut, which can cause them to be excessively fermented by gut bacteria.

This fermentation releases hydrogen gas that could lead to distension of the intestines, which can cause uncomfortable IBS symptoms in some people, such as pain, gas, bloating, constipation, and diarrhea. This would be considered a FODMAP intolerance, and tends to be related to functional issues like small intestinal bacterial overgrowth (SIBO.)

Most of the high-FODMAP foods are actually healthy whole, foods, but again, that doesn’t mean they work well for everyone. If you think you are FODMAP intolerance, try avoiding or severely limiting the following foods, at least temporarily, to see if it helps:

Vegetables:

Artichokes, asparagus, beetroot, celery, garlic, onions, leek bulb, legumes, Savoy cabbage, sugar snap peas, sweet corn

Fruits:

Apples, mango, nectarines, peaches, pears, plums, watermelon

Dairy:

Milk, cream, custard, ice cream, soft cheeses, yogurt

Grains:

Rye, wheat-containing breads, cereals, crackers, pasta

Nuts:

Cashews, pistachios

Fructose, one FODMAP sugar, is one of the more common intolerances. Fructose intolerance (6) is often found in people with recurring stomach pain and bloating. The goal with treating a FODMAP intolerance is not to remove the foods forever but to heal the gut so that you can eventually increase your intake of these foods, especially the high-FODMAP fruits and vegetables, which are valuable sources of nutrients.

9. Dairy

Casein, a protein found in animal milk and products made from it like ice cream and cheese, is another common sensitivity. But there is more to the dairy story. Cows on most major dairy farms are routinely given hormones to increase milk production and antibiotics to combat mastitis infections. They also tend to live in unhealthy, unclean conditions, and are fed corn instead of their natrual food, grass. Their milk is then typically pasteurized (super heated) and homogenized (blended) and the fat is often removed. To make up for this highly processed product having so little remaining nutrition, synthetic vitamins are typically added back into milk, in an attempt to simulate what nature had already included in the first place, in its whole-food form.

Organic dairy is better because it does not allow the use of hormones and antibiotics. Fermented dairy, such as grass-fed kefir and yogurt, is even better, as it mitigates some of the problems people have with casein sensitivity and includes beneficial bacteria, so it may be better tolerated. However, some people can not ever have any dairy, in any form.

10. Nuts and seeds

The roughage of nuts and seeds, and well as the lectin and phytate proteins, can irritate some people’s digestion. Plus, most nuts sold in stores are typically coated in inflammatory industrial seed oils, like soybean or canola oil. They could also contain partially hydrogenated trans-fats, which can contribute even more to inflammation. I find that people who are intolerant to nuts typically do better buying them raw, soaking them, and lightly toasting them at home. I also recommend enjoying them sparingly.

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